Chipset Cooling

How-To – Jason Choong

Is it worth the effort cooling a chipset?

Overheated system chipsets can cause instability, causing unpredictable system crashes. It tends to happen when an inferior wafer/die is used in manufacturing. If the power dissipation exceeds specification, cooling is required or it will kill the chip. That’s why el-cheapo VCD players always break down – so you have to buy again.

Many chips didn’t get to see the open market – they died in the assembling plant. Those that made it are tortured to death by extreme heat. As a rule of thumb, if we lower semiconductors temp by 10ºC, we can double its lifespan. How good are these chipsets?

The VIA KT400 on my MSI MBM was way too hot; the heat sink was burning hot. After several failed attempts, I decided to superglue a Pentium 200 MMX heatsink on it. Wow! The heat sink was as cool as room temp. Then I used the original heatsink and superglued it on the Southbridge VT8237, which was not very hot.

I’ve tried mounting a heatsink to the power transistors of my MSI KT3 Ultra MBM with liquid superglue. It lowered the temp by a degree or two with fan cooling. It’s been at least six months and the heatsink didn’t drop off. At moderate temp, these non-heat-resistance super glues seem to hold. Once glued, it’s almost impossible to get it off. Using excessive force might rip the chipset’s plastic/ceramic mould. I used Loctite super liquid glue in my projects.

The VIA KT333 and KT400 release quite a lot of heat. The Pentium 586 heatsink has about 135 cm² of surface area. With a forced air convection, the KT400 chip was only a little warmer than ambient. If we use, say, a passive heatsink with only 96 cm² on the KT333, it gets quite warm. For the Southbridge VT8235 with 96 cm² of surface area, it is not required as it releases less heat. The first test was conducted after at least a few hours after bonding. Subsequent power ups were done after half an hour.

The SBlive chipset is quite hot; with 10 cm², the heatsink itself is still bloody hot! I used 48 cm² heatsink. These heatsinks can be obtained from an electronic surplus shop. We can also dismantle some old electronics gear to get some useful heatsinks. Old Celeron heatsinks are small and efficient enough for Northbridge chipsets and hot AGP chips, but you may have to sacrifice a PCI slot.

If you decide to make removable mounted heatsinks or testing a heatsink, there’s one way I’ve done it¹ – this is important if the product is still under warranty.

First put an aluminium tape on the chip, then glue the heatsink on. With enough force, the heatsink will come off. The most it will screw up is the tape, not the chip. Gluing a heatsink on a hard disk is not going to do too much. The best option will be to blow the HD with a fan, preferably from the bottom, cooling the board as well. Some chips on the HD are quite hot, so cooling it may be a good idea.

I told my friend about it. He went to the extent of gluing the Athlon-like Intel chipset. I tried to say no but he did it anyway. The heatsink seemed to hold. It solved his overclocking problem – sometimes it’s the chipset that cannot tolerate the overclock, not the CPU.

¹ED NOTE: A simpler alternative is to use thermal tape for heatsink mounting – adding small pieces of aluminum in electronic gear could lead to some problems.

Jason Choong