Most of the articles here on the Heatsink Guide are highly technical and for a very targeted audience. However, many of the visitors of this site are actually looking for simple answers to simple problems, without getting too much into the details.

This is why I created the Cooling FAQ. If you're just looking for an answer to a common cooling-related problem, you've come to the right place.

This section covers both standard PCs for home/office and notebooks.

If your question isn't answered here, don't hesitate to ask in the discussion board! The board doesn't require registration, and I read and reply messages regularly.

Office/home computer cooling questions

My PC crashes frequently / is very slow! Is it overheating?

Most PC crashes are not related to overheating, but to bad operating system configuration, or other defective hardware (memory, motherboard, power supply...). Slow PC speed is typically related to software/operating system issues; however, Pentium 4 (and later) CPUs have feature thermal throtteling, so overheating may indeed cause the PC to be very slow.

Use software like Motherboard Monitor to observe CPU temperatures, or check the BIOS CPU temperature readout to get an estimate of your actual CPU temperature.

My CPU is very hot! What should I do?

Many people tend to underestimate the maximum allowed CPU temperatures. Please refer to the "maximum CPU temperatures" article to find out if you CPU is acutally overheating, or if it's still within its allowed temperature range.

I compared my CPU's temperature to the maximum allowed temperature, and it's indeed running too hot.

In this case, you have to do something about your cooling system. The first step is to check the CPU fan, the air intakes of your case, and all case fans for accumulated dust. With PCs that have been running for many months, and thus have become dusty on the inside, removing dust alone can bring down temperatures drastically. Use a vacuum cleaner (while the PC is turned off, of course). When you approach the vacuum cleaner to CPU or case fans, it will cause them to spin - no problem, they won't be damaged if that happens.

If dust isn't the reason for your temperature problem, you need to install additional cooling hardware. You can lower CPU temperatures either by improving case cooling, or by improving CPU cooling. My recommendation is to try to improve case cooling first, for the following reasons:

When shopping for a new case fan, first check your case for fan bays. They are usually located on the rear of the case, below the power supply fan - this is the best location to improve CPU cooling. Other locations include the lower front of the case (below the drive bays), or the side panel. Fan bays on the front of the case may not be visible from the outside.

Fan bays typically come in two sizes, 80x80mm (most common) and 120x120mm. Determine your fan bay's size (if it has bays of different sizes, chose the larger one), and buy a 80mm or 120mm fan. Fans can either have "power supply style" four-pin connectors, or MOLEX 3-pin connectors. The MOLEX 3-pin connector allows fan speed monitoring through the motherboard; but if you don't know whether your motherboard has free fan connectors, you might want to buy a fan with a power supply connector to be on the safe side. Some fans that come with 3-pin MOLEX connectors also come with a power supply connector adapter.

When you have your new fan, install it in the selected drive bay. Whether you have it blow in or exhaust air depends on the location of the fan - observe the rules from the case cooling section of this site.

My CPU fan has failed! What should I do?

If your machine is still on warranty, have the manufacturer or retailer handle it.

If it isn't, you need to replace the CPU fan. Open your case and look at the CPU cooler. Does it consist of a heatsink with a normal (square) fan screwed to it on top? If so, then I'd recommend to change the fan only and leave the CPU heatsink installed, for the following reasons:

Measure the fan size (outer dimensions of the square fan case). It will typically be 80mm or 60mm, or 50mm or 40mm for older PCs. Buy a fan of the same dimensions - they are widely available (only in the unlikely case that your fan has an unusual format, e.g. 70mm, you might have problems finding a replacement). It should have the same connector as your old fan, typically 3-pin MOLEX, but older PCs may have fans with 4-pin power supply connectors. It should also run at the same speed, or faster, as your old fan - if you don't know your old fan's speed, buy a fan that has a similar or slightly higher power rating, in watts. Install the new fan the same way the old fan was installed. Don't forget the power connector!

If the fan is integrated into the heatsink's structure, it usually cannot be replaced by another stock fan. In this case, you need to replace your entire CPU cooler by another cooler suitable for your particular CPU model and socket format. If you don't know your CPU model and socket format, or if you don't feel comfortable about changing the CPU cooler, better ask a friend, or take the PC to a local repair shop.

Notebook cooling

My notebook is suddenly making lots of noise! What should I do?

The amount of noise your notebook makes depends on many factors - obviously, on the operating temperature and the CPU load, but also on the operating system configuration, installed drivers, and the BIOS. Did you reinstall your OS before the problem occured? Installed new drivers? Upgraded the BIOS?

In some cases, it may help to put your notebook back to its original operating system configuration with the aid of a recovery CD (or recovery partition) supplied by the manufacturer.Refer to you notebook's documentation for instructions how to do that.

If you believe that the noise is related to a defect in the notebook's cooling system, read below.

My notebook is running too hot! What should I do?

First, check if it's really running too hot. Some notebooks are designed to withstand high temperatures without damage. Even when your notebook's lower side gets so hot that it may feel uncomfortable on your lap, it may still run within its allowed temperature range. Use a tool to observe CPU temperature (or look at the BIOS temperature reading), and compare it to the maximum allowed temperature for your CPU. Note that maximum temperatures for notebook CPUs can be very high - sometimes over 100. You can find the maximum temperature of your CPU here.

It is also normal for notebook fans to power up only when required. So even if your notebook is quite hot and the fan still isn't spinning, this may be normal.

It's unlikely that your notebook shipped with an insufficient cooling system. If it exceeds its maximum allowed temperature, this is due to a defect. If your notebook is still on warrantly, let the manufacturer or retailer handle it.

My notebook's cooling system is defective! What should I do?

If your notebook overheats (and possibly shuts itself down) or is excessively noisy, the cooling system may be defective. If your notebook is still on warranty, let the manufacturer handle it, instead of voiding the warranty by messing with it yourself.

Even after the warranty expired, it may be wise to let the manufacturer handle it. Replacing a notebook cooling system isn't as easy as replacing a cooler on a desktop PC. If your notebook's manufacturer is known for excessive repair prices, try a third party company specialized in notebook repairs. Google will help.

If you insist that you want to repair it yourself, open the notebook locate the fan. A notebook cooling system typically consists of a combination of heat pipes, heatsinks, and small fans/blowers. If you're lucky, you can find a small standard fan or blower with a manufacturer and model name on it (e.g. Nidec, Sanyo Denki, NMB...). Use Google to find a source for a replacement part. If you can't find a manufacturer or model name, but the fan looks like a standard part, you can usually replace it with another model of the same size, voltage, and power rating. Typically, this will involve soldering. Some notebooks use custom blowers integrated into the heatsink. In this case, you might be out of luck. If the fan's bearing is accessible, a drop of oil on it may at least temporarily solve the noise issue.

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