HARD DRIVE AND CPU TEMPERATURES ON A
2.80C GHz PENTIUM 4 PC SYSTEM

Author:  Mike Boesen   (mboesen@gmail.com)

Last updated: 23 March 2006

1.  Background

This article is a follow up to an article I wrote for the PC Users Group magazine Sixteen Bits, describing applications that are useful in monitoring the temperatures of the CPU, motherboard and hard drives.  The most up to date version of that article is here: http://www.pcug.org.au/~boesen/temperature_software/temperature_software.htm ).   I used the applications when undertaking a number of tests on my PC to see how different circumstances affected the temperatures of hard drives, the CPU and motherboard.  This new article summarises the results of those tests.  I'll incorporate any improvements that people might suggest in an up to date version that is kept on my web site.

What lead me to become interested in temperatures was assistance that I gave to a number of PC users who were having problems with their PCs.  I felt that in a few problem cases the possible cause was overheating.  Initially, my initial concern related to hard drives and the CPU.  

To be better informed about this topic I undertook a number of tests with my own PC.  In these tests I observed the temperatures of the CPU, motherboard and hard drives under a number of conditions:  different fan fan speeds, fans on and off, drive mounted internally and drive in removable caddy, idling and loaded conditions.  

Taking into account the tests and my experience with other persons' PCs and from information that is available on the web, I am now of the view that it is unlikely that CPU temperature problems will occur for the vast nmajority of PC users.  On the very few occasions that I have encountered CPU overheating problems it was because the CPU cooler had been installed inappropriately.  On the other hand, I suspect that hard drive temperatures may possibly be a cause of some problems and that the life of some hard drives are likely to be shorter than they might otherwise be. 

2.  How hot is too hot?

2.1  CPU temperature

Modern CPUs are built to operate quite efficiently even when they are quite hot.  For the Pentium 4 series for instance, Intel's stated maximum "case temperatures" are between 66 and 78 C.  The "case temperature" is the temperature measured at the centre of the CPU's heat spreader - NOT the temperature of the PC's case.  For my P4 2.80c CPU, Intel indicates that the maximum temperature is 74 C.   Table 2 in this Intel article about Pentium 4 processors provides details about maxima for various versions of the P4:  http://support.intel.com/support/processors/pentium4/sb/CS-007999.htm  An abridged version of the table is below in Appendix 1.  

CPU temperatures will change rapidly in accordance with how much work the CPU is undertaking.  A large range in temperatures for a CPU is quite normal and depends on the amount of work being undertaken, the ambient air temperature, the type and effectiveness of the CPU's cooling system and the ventilation conditions within the PC's case. 

In the absence of specific information about the manufacturer's maximum operating temperature for a CPU,  I would be concerned if a CPU's temperature exceeded 65 C when the CPU is under heavy load and the ambient temperature is 27 C or less. 

However, even if the manufacturer's maximum operating temperature is exceeded, a modern CPU such as the Intel Pentium 4 series is designed to slow itself down automatically, reducing power consumption and hence limiting the overheating to a tolerable level.  This is referred to as ''thermal throttling'' or simply ''throttling''.  When such CPUs get really hot - around 95 to 100 C they are designed to shut down completely.  Infrequent shutdowns of this nature should not affect the operating life of the CPU but frequent shut downs can affect the life of the CPU.  

If you want to see some nice charts showing throttling in action, have a look at this article:  
http://www.digit-life.com/articles2/p4-throttling/index.html   The testing conducted is described thus by the authors:  ''...we conducted a very simple experiment on two top Pentium 4 3.2 GHz CPUs, one with a Northwood core and the other with a Prescott.  With the CPU loaded at 100 percent, we powered off the cooler fan and watched the temperature rise and the performance decrease as time went by.''

There are a number of possible causes of excessively high CPU temperatures.  My servicing checklist is this:

• Is the CPU cooler (fan plus heatsink) attached properly to the motherboard so that the heatsink is locked snugly onto the CPU?  If the mounting clips are loose or unattached, this can have a VERY BIG effect on temperatures.  Check gently to see if the cooler assembly is wobbly.  Check clips visually.
  
  
• Is the fan on the CPU cooler operating reliably?   Check speed.  Check for bearing noise.   Check for loose plug and sockets.  Clean fan's fins if there is a lot of accumulated guk (use a long-haired small flexible brush and vacuum cleaner to fix).
  
  
• Are the fins on the cooler's heatsink clogged up with accumulated dust and guk so as to prevent air flow?  Use a long-haired small flexible brush and vacuum cleaner to fix.
  
  
• Is the cooler's heatsink interfaced with the CPU using an effective heatsink interface material?  This would be an extremely low frequency problem and requires removing the CPU cooler, so unless you are a technogeek, don't fiddle with this.
  
  
• If the only fan in the case is the one in the Power Supply Unit (PSU),  make sure that fan is operating reliably and exhausting hot air out the back of the case.  Clean fan's fins if there is a lot of accumulated guk.
  
  
• Check that any other case fans are operating reliably.  Rear mounted case fans should be exhausting warm air out the back of the case.  Front mounted intake fans should be sucking air into the case.  Clean fans' fins if there is a lot of accumulated guk.

2.2  Hard drive temperature

Information available on the web about the effect of heat on hard drive reliability suggests that heat affects the reliability of the operation of a hard drive's components and its service life.  For instance, this statement is made by one author: '' Moreover, reliability and durability of these drives depends much on their operating temperatures. According to our research, increasing HDD temperature by 5°C has the same effect on reliability as switching from 10% to 100% HDD workload! Each one-degree drop of HDD temperature is equivalent to a 10% increase of HDD service life.''  ( http://www.digit-life.com/articles2/storage/hddpower.html )

The rotation speed of the platters in a hard drive has a very marked effect on temperature.  This is because the rotating platters in the drive generate heat through air friction and the faster they spin, the more heat is generated.  Therefore modern 7,200 rpm drives can generate a lot of heat that needs to be dissipated.  Heat is also generated by the spindle motor and other electronic components.  

Hard drive manufacturers provide information about the claimed minimum and maximum operating temperature for their hard drives.  These maxima vary depending on the brand and model of the drive.  Once again, if you really want to know what the maximum operating temperature is for a hard drive, you will need to do a Google search.  For example:

• for 7,200 rpm Maxtor Diamond Max 10 drives, the manufacturer's stated maximum operating temperature is 60 C. 
• for 7,200 rpm Maxtor Diamond Max 9 drives, the maximum is 55 C.
• for the Seagate ST340014A Barracuda drive the maximum is 69 C
• for the Seagate ST3200822A and ST3200021A (PLUS) models the maximum is 64 C.  

I suspect that the setting of maxima may be a little arbitrary and that a manufacturer would be unable to provide a really scientific basis for the temperature stated.  However, what seems to be generally agreed is that the service life and reliability of a hard drive will be affected by the temperature of the drive,  irrespective of whatever the claimed maximum operating temperature is.  My own rules of thumb (rule of thumbs?) are: 

1. keep the drive temperature as low as possible
   
2. be concerned if the drive temperature exceeds 50 C. 

If excessively hot drive temperatures are noted there are a number of possible causes.  Virtually all are related to inadequate air flow over the hard drive.  The importance of achieving such ventilation cannot be overemphasised.  To improve ventilation I'd recommend consideration of these solutions: 

• Ensure that there is a good air space between multiple drives and between a drive and any other other device or object that might constrain air flow.  Wherever possible, avoid installing multiple hard drives in adjacent drive bays.
  
  
• If the PC has no case fans, make sure that the fan in the power supply unit is operating correctly and reliably.
   
• Increase ventilation by installing either a front intake fan or a rear exhaust fan (or both). 
  
  
• If there is a front intake fan, position the hard drive/s so that the intake air is directed over and under the drive/s. 
  
  
• Ensure that there is some form of air intake aperture at the front of the case near the hard drive/s.  This is needed to ensure that any air drawn into the PC case will ventilate the drive/s.  Close off any unnecessary apertures that would be preventing such an air flow occurring (e.g. missing PCI slot baffles,  open optical drive bays, redundant ventilation holes that do not promote an effective ventilation path).
  
  
• Ensure that cables are situated so as to minimise obstruction of air flow inside the case.   If the location of flat 40-core or 80-core hard drive or optical drive cables is a problem, replace flat cables with round cables.  (But note that if there is no air flow over the drive/s this may be be a pointless expenditure.)
  
  
• Ensure that removable caddies or their cradles have an exhaust fan and the caddy/cradle design is effective.
  
  
• Ensure that external drive enclosures have fan ventilation (may not be necessary for the small drives that are normally used for laptops). 

3. Testing conditions

The PC that I undertook my tests on had these components:

• Antec SLK3700 case, with a 120 mm Antec exhaust fan at the rear of the case (see Appendix 2) and a 120 mm Spire intake fan at the front of the case.  For both fans, I cut out the grille that comprises holes drilled in the PC case's wall.  I did this to maximise the airflow created by the fans and to eliminate any noise caused by air turbulence.  In place of the original grilles I installed thin wire grilles to prevent ingress of tiny fingers (see Appendix 3).   Because of their size and the grille modification, the large fans move a lot of air very quietly.
  
  
• Case fan speeds manually controllable through a Super Flower Fan Master unit mounted in an optical drive bay.
  
  
• Zalman ZM400B-APS power supply unit (PSU).  This has one internal exhaust fan with its speed governed by the temperature of the PSU's heat sink.   When the PC is idling and the temperature has stabilised, the fan is inaudible.
  
  
• CPU:  Intel 2.8 GHz Pentium 4 (2.80c)
  
  
• CPU cooling via a Zalman CNPS 7000 Al-Cu CPU heatsink and fan (see Appendix 4).  The fan speed is controllable through settings in the PC's BIOS.   The fan is quieter than the stock Intel cooler fan.
  
  
• Internally mounted hard drive:  7,200 rpm 120 GB Maxtor Diamond Max 10 with a Serial ATA interface.  The drive is sited directly in front of the airflow generated by the front case fan and there is no other drive or device or airflow obstruction in close proximity (see Appendix 5).
   
• removable drive mounted in a Laser brand caddy inserted into a cradle positioned in an optical drive bay:  7,200 rpm 250 GB Maxtor Diamond Max 10 with Parallel UATA interface.  Cradle has a 40 mm exhaust fan that sucks air through the front of the caddy, over the drive and then into the inside of the PC's case.  The fan is only ever on when the caddy is fully inserted - see  http://www.pcug.org.au/~boesen/backup_devices/caddy_fix.htm  if you are interested in how I achieve that.

I monitored temperatures of my drives and CPU using the freeware application Motherboard Monitor 5.  (See details in http://www.pcug.org.au/~boesen/temperature_software/temperature_software.htm )

All my tests were conducted with the speed of the CPU cooler's fan slowed to 2,150 rpm (versus the maximum possible of 2,660).  Because of the efficiency of the Zalman cooler design and my use of two case fans I can run the cooler fan at this slower speed maintaining the CPU at an acceptable temperature, with virtually inaudible cooler fan noise.  

I monitored temperatures under various conditions:

• Front and rear case fans off, then slowed (to about 1,500 rpm) and then at full speed (about 2,540 rpm).  Results reported below in relation to the slowed fan rate may be indicative of what the situation might be if smaller case fans were used at full speed.
  
  
• CPU at idle (no programs running actively) then CPU at 100% full load.  The full load condition was achieved using the application Stress Prime 2004.  This excellent freeware application is available from  http://sp2004.fre3.com/  To achieve 100% CPU utilisation I had to run two instances of SP2004 simultaneously because my CPU has hyper threading enabled.  
  
  
• Hard drives at idle and then under heavy load.   The heavy load condition was achieved by making a compressed backup of the 95 GB of data on my internal SATA drive onto the removable PATA drive using Acronis True Image (see http://www.acronis.com/homecomputing/products/trueimage/  )   This heavy load condition was not as severe as could possibly be achieved but I felt that it was about as severe as most PC users would ever encounter.  However, some data processing applications that involve really heavy disk read/writing might generate marginally higher drive temperatures. 

My tests were undertaken in January 2006 (i.e. Summer here in the antipodes) and during days when the ambient temperature in the computer room was between 25 C and 27 C. 

4.  Test results

I won't bore you with the results of all the tests (the stuff below is boring enough).  However, here are the highlights, presented in summary form. 

4.1  CPU temperature results

• CPU at idle:
  • 43 C with no case fans on
  • 37 C with only rear case fan on full
  • 39 C with only front case fan on full
  • 36 C with both case fans on full
    
    
• CPU 100% loaded:
  • 60 C with no case fans on
  • 54 C with only rear case fan on full
  • 58 C with only front case fan on full
  • 54 C with both case fans on full
    
    
  So:
  • When idling, the CPU stays nice and cool (43 C) even with no case fans operating.
  • However, one or two case fans make it even cooler at idle - between 36 C and 39 C.
  • At idle one rear case fan is just a little more effective than a front case fan and brings the temperature down to 37 C.
  • Under full load and with no case fans operating, the CPU gets quite hot (60 C) but still comfortably below the maximum of 75 C for my CPU .
  • However, one or two case fans ensure that it is even cooler under full load.
  • Under full load, one rear case fan is a little more effective than the front case fan and brings the temperature down  to 54 C - some 23 C below the maximum.
  • At idle and under full load, there is no real gain through having both a front case fan and a rear case fan. (But note that this applies to the CPU temperature - the story for hard drive temperatures is quite different!)  

I also undertook testing with the case fans running at slowed speed.  The results are consistent with the patterns in the above results, with temperatures being only about 2 C lower than those above.

4.2  Internal hard drive temperature results

• drive idling:
  • 55 C with no case fans on
  • 50 C with only rear case fan on full
  • 40 C with only front case fan on full
  • 35 C with both case fans on full
    
    
• with heavy drive activity:
  • 64 C with no case fans on
  • 54 C with only rear case fan on full
  • 41 C with only front case fan on full
  • 39 C with both case fans on full
    
    
  So:
  • When idling with no case fans on, the hard drive gets very hot - 55 C, or only 5 C below the maximum operating temperature. 
  • During heavy drive activity with no case fans on, the drive's temperature at 64 C exceeded the maximum operating temperature by 4 C - a big worry!!
  • Turning the front case fan (only) on full brings the drive temperature down by a significant amount:  to 40 C at idle;  or to 41 C under heavy load. 
  • Turning the rear case fan (only) on full also provides some reduction in temperature:  to 50 C at idle and 54 C under heavy load.  However these reductions are smaller that was achieved for the front case fan.  This suggests the importance of achieving air flow over the drive itself.
  • With the two case fans on full, the idling temperature drops to 35 C at idle and to 39 C when undertaking heavy work.  So the total temperature benefit compared with the no fans situation is 20 C at idle and 25 under heavy load!
    

I also undertook testing with the case fans running at slowed speed.  The results are consistent with with the patterns in the above results, but the cooling effectiveness is about 5 C less than with a fan or fans running at full speed. 

4.3  removable hard drive temperature results

• drive idling:
  • 36 C with no case fans on
  • 36 C with only rear case fan on full
  • 41 C with only front case fan on full
  • 36 C with both case fans on full
    
    
• with heavy drive activity:
  • 44 C with no case fans on
  • 45 C with only rear case fan on full
  • 49 C with only front case fan on full
  • 41 C with both case fans on full
    

So:

• Under all the test conditions the temperature of the drive in the caddy was never greater than 49 C. 
  
  
• Surprisingly, the worst performance (49 C) was under heavy load when the front case fan was running at full speed and there was no rear case fan operating.   I assume that this is because the front fan is then generating a positive pressure inside the case, decreasing the ventilation effect of the small fan inside the cradle in which the caddy is inserted. 
  
  
• The best performance under heavy load was 41 C when both case fans were on full.

I also undertook testing with the case fans running at slowed speed.  The cooling effectiveness is about 2 C less than with a fan or fans running at full speed.

5.  Conclusions

5.1 Caveats

Keep in mind that my conclusions reflect results for a system that:

• Has a moderately powered (70 W) CPU ( Intel 2.80 c Pentium 4).   Other CPU's will generate a lesser or greater amount of heat and may have different temperature maxima.
  
  
• Has a very efficient CPU fan and heatsink (Zalman) even though operating at a slow speed (2,150 rpm). 
  
  
• Has large case fans (120 mm) mounted over unobstructed ventilation ports.  Smaller case fans will provide poorer ventilation unless they are operating extremely fast (and hence generating a lot of noise).   Ventilation effectiveness will also be a function of the speed of a fan and its blade and shroud design.  It will also be a function of the construction of the ventilation ports - if the port has small ventilation holes in the port then the airflow will be constrained.
  
  
• Has a caddy/cradle design (Laser) that maximises the effectiveness of the airflow produced inside the caddy by the small 40 mm fan in the rear of the cradle.  Other types of caddies will have less airflow if they do not have a fan, or if the cradle and caddy do not mate in a way that maximises airflow over the drive.
  
  
• Has a power supply unit (Zalman) that has its own very effective internal fan.
  
  
• Has fast (7,200 rpm) Maxtor hard drives that generate a fair amount of heat.  Heat generated by other brands and models of drives may be greater or less.  They may have different manufacturers' specifications regarding maximum operating temperature. 
  
  
• Has only one internal hard drive that is sited directly in front of the airflow generated by the front case fan and which has no other drive or device or airflow obstruction in close proximity (see Appendix 5).  Equivalent drives that are less favourably located will have considerably higher temperatures.
  
  
• Is not designed for or used for applications that require a really powerful video card or multiple video cards.  The Graphics Processing Unit in my PC is an Nvidia GeForce FX 5700.  So the amount of heat being generated by the graphics card in my PC is minimal. 
  
  
• Was tested when the ambient air temperature was about 27 C.   Lower ambient temperatures will mean lower CPU and drive temperatures, and the opposite will apply for higher ambient temperatures.

5.2  Conclusions about my own PC

1.  CPU temperature: 

• Even when running at 100% load, and with the two case fans turned off, my CPU temperature of 60 C was comfortably below the maximum of 75 C - a safety margin of 15 C.
  
  
• However, if I ever wanted further assurance that I would never exceed the maximum temperature under full load, then running the rear case fan alone would provide a big safety margin of about 23 C running at full speed or about 21 C when running at reduced speed .
  
  
• The front case fan would not provide any further benefit over the rear case fan.   However, running it would have no negative effects on CPU temperature (and would have a positive benefit for the temperature of the internal hard drive - see below).

2.  Internal hard drive under heavy load: 

• With no case fans operating, the internal drive would become hotter than the manufacturer's stated maximum under heavy load.   That is an unacceptable situation.
  
  
• If run at slow speed, I'd be very concerned about whether or not the 120 mm rear case fan by itself would be enough to keep the temperature lower than the maximum of 60 C under heavy load.   Also not an acceptable situation.
  
  
• If run at full speed, the 120 mm rear case fan by itself still would not provide sufficient cooling:  the drive would be at 54 C.
  
  
• If run at half speed, the rear case fan by itself does a better job than the rear case fan, but the drive is still a very warm 46 C.
  
  
• If run at full speed, the front case fan by itself does a better job than the rear case fan, and the drive is a tolerably warm 41 C. However this option would not be a good one because having the rear fan in operation has benefits for the CPU temperature and the temperature of a drive if it were to be in the removable caddy (see below).
  
  
• If both 120 mm case fans are run at slow speed, under idling conditions the temperature of the internal hard drive is about 30 C.  In my view this is quite an acceptable temperature.  So what I will do when the PC is idling or I am doing work that requires infrequent or intermittent read/writes to the hard drive, is to turn both fans to the slowed speed. 
  
  
• However, if both 120 mm case fans are run at slow speed under heavy load the drive would be quite warm at about 44 C.  In contrast, running both 120 mm fans at full speed would ensure that under heavy load the drive was kept at a reasonably low temperature of 39 C.  So when I am undertaking work requiring heavy disk activity (e.g. creating a compressed backup, defragmenting, virus scan of the whole drive), I will run the fans at full speed.  An associated cost is a slight increase in fan noise.  However, because of the large fan diameters and the absence of a punched metal grille, the fan noise is very muted and is only a gentle whooshing.  In any event, when such heavy disk activity is being undertaken, I am elsewhere.

3.  removable hard drive in a caddy when under heavy load: 

• With both case fans operating on full, the temperature of the removable drive would be a tolerable 41 C.
  
  
• The effectiveness of the small fan is greatest when there is a front and rear case fan operating, and worst when there is a front case fan operating but no rear case fan.
  
  

4.  In the light of the above findings, I am now confident that this hardware configuration will ensure that the temperatures for my drives and the CPU will never exceed the maxima, and there will be very little fan noise:

• CPU cooler fan (running at the reduced speed that applied during all the tests).
  
  
• 120 mm rear case and 120 mm front case fans normally running at reduced speed and only run at full speed when very intensive disk operations are being undertaken.  This change in speed is possible on my system because I can control the speed of the case fans using the Fan Master unit.
  
  
• 40 mm cradle fan ventilating the drive in the caddy on the occasions that it is inserted (but fan off when no caddy is inserted).
  
  
• Internal drive situated directly in front of the airflow generated by the front case fan and with no other drive or device or airflow obstruction in close proximity.

5.3  Recommendations that other PC users may wish to consider

Here are some recommendations for others to consider in respect of their PCs:

• If your CPU cooler (fan plus heatsink) is correctly installed and appropriate for the CPU, and there is at least one effective exhaust fan (e.g. that in the the power supply unit), it is unlikely that the maximum operating temperature for the CPU will be exceeded.
  
  
• If you ever have any reason to believe that your CPU is overheating, it could be useful to find out what the maximum operating temperature is for your CPU and to do a spot check on its temperature during some process that involves heavy CPU activity.   The freeware application Everest (see http://www.pcug.org.au/~boesen/temperature_software/temperature_software.htm ) can tell you the CPU temperature and the freeware application SP2004 (see  http://sp2004.fre3.com/ ) can be used to put the CPU under 100% load.
   
• While I'd guess that CPU temperatures in the vast majority of PCs would be OK, I'd also guess that there are quite a number of PCs that have hard drives that will be operating at higher than acceptable temperatures during times when the hard drive is undertaking heavy work (e.g. during the creation of a backup clone or compressed backup or a defragmentation).  The reason I say that is that in my PC, with a single drive mounted well clear of any other drives or hardware, with an air intake vent located in front of the drive, a large rear case fan mounted over an unobstructed port and operating at half speed, the drive temperature under heavy load was only 1 C lower than the maximum.  I have seen many PCs that have either no case fans, or only a small rear case fan mounted on a small-holed exhaust port, with hard drives sandwiched on top of each other or tucked away with optical drives at the top of the case (the hottest part of the case), and no suitably located air intake vent.  The temperature of at least some such drives will be exceeding the manufacturer's stated operating temperature and others will have drives that are running unacceptably hot.
  
  
• If you ever have concerns about hard drive temperatures, it could be useful to find out what the maximum operating temperature is for each drive and to do at least a spot check of temperature during some process that involves heavy drive activity. To stress the drive, run some disk-intensive activity (e.g. backup, virus scan, defragmentation).
  
  
• The freeware applications HDD Thermometer, HDD Health and Everest (see http://www.pcug.org.au/~boesen/temperature_software/temperature_software.htm ) can tell you the drive temperatures are for drives that have SMART (Self Monitoring and Analysis Reporting Technology) implemented.  For more information about SMART and which of the SMART attributes are critical, see http://en.wikipedia.org/wiki/Self-Monitoring,_Analysis_and_Reporting_Technology  Most modern drives implement SMART.   HDD Thermometer can be configured to show real time drive/s temperature/s all the time in the system tray.  HDD Health can be configured to monitor the temperature and other attributes of your drives, to display the temperatures on request and to provide a warning whenever the temperature of a drive exceeds a limit that you select. It can also provide an predictive estimate of the health of your drives.  It is very much worthwhile configuring HDD Health to load automatically whenever you start your PC. Everest is good only for a spot check on drive (and CPU) temperatures.  
  
  
• If a drive's temperature appears to be too high under load, consideration should be given to these types of fixes:
  
  
  • Relocate hardware so that that there is an air space between each drive and other hard drives or other devices. 
    
    
  • Relocate dual drives so that they are not in adjacent drive bays. 
    
    
  • Install a front intake fan or both front and rear fans. 
    
    
  • Make sure that there is an air intake aperture at the front of the case near the hard drive/s.  Position the hard drive/s so that any drawn in air flows over and under the drive/s. 
    
    
  • Close off any unnecessary apertures that would be preventing an air flow occurring across the drive/s.
    
    
  • Relocate cables to minimise obstruction of air flow inside the case.   If the location of flat 40-core or 80-core hard drive or optical drive cables is a problem, replace flat cables with round cables.  (But note that if there is no air flow over the drive/s this may be be a pointless expenditure.)
    
    
  • Only use caddy/cradle units that have an exhaust fan and that have an effective design in terms of air flow route.  Check periodically to make sure that the exhaust fan is still functional (being small, they can wear out quickly).
    
    
  • Only use external drive enclosures that have fan ventilation (may not be necessary for the small drives such as the Travelstar that are normally used in laptops)
    
    
  • If noise from additionally installed case fans is a concern, consider installing a fan speed control unit.  There are many types of such units, ranging in price from $25 AUD to about $100 AUD. 
    

Appendix 1.  Boxed Intel Pentium 4 Processor Thermal Specifications

Source:  http://support.intel.com/support/processors/pentium4/sb/CS-007999.htm

Note:  This table is an abridged version of the original table in the source.

Appendix 2.  Rear case fan

Rear case fan is 120 mm Antec.  Note the grille behind the fan's blades.  Fan is attached to case using zip ties with silicon pads behind each corner of the fan to minimise any noise due to vibration.  The Zalman cooler is in the foreground.  Another view of the Zalman cooler is shown in Appendix 4.  

Appendix 3.  Grille for rear case fan

Fan's grille is on the right.  Original punched hole port for this fan has been nibbled out.  Not elegant, but is effective.  The smaller grille is on the Zalman power supply unit. 

Appendix 4.  Zalman cooler

The cooler consists of the heatsink (the thing with all the fins) with a integrated fan the centre.  The black object on the left is the rear case fan.   ASUS P4P800E-Deluxe motherboard..

Appendix 5.  Drive bay

The drive bay has space for 5 drives, only one of which is occupied by the 120 GB SATA drive.  The ANTEC case is extremely well designed.  Note the rubber grommets for mounting screws.  The drive cage is removable. 

The orange object is a 120 mm fan at the front of the case.  This is a slow-revving Nexus 'Real Quiet' fan which I am currently testing in place of my normal 120 mm Spire fan.  The fan is attached to case with zip ties and silicon pads under each corner. 

Mike Boesen