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Wednesday, 29 December 2010

Acer Laptop Fan

I have an Acer Aspire 5920G laptop. By today's standards it is archaic, an early 2Ghz dual core processor, 4 Gb of 667mhz ram. However, the machine is brilliant - the screen is pretty good for the cost, it looks good, has good sound (for a laptop), works well (having now hosted Vista, Windows 7 Ultimate @ 3 bit & Windows 7 Pro in 64 bit, boy was Vista junk).

I've upgraded the hard disk to a faster larger model which makes a small amount of difference to performance but nothing worth worrying about.

The big downer is the fan. The Acer cooling system cools both the graphics card (Radeon Mobility 3470 - again, pretty high spec for a laptop when it was new) and the processor. Unfortunately it does this by running fast and loud and when temperatures go up it runs loud enough to be heard not only in the next room but downstairs too - frankly sitting at the desktop in from of the laptop it was deafening.

I've tried a couple of laptop coolers - I had an Akasa Orion laptop cooler but its fans were worse than the laptops, I had a block of wood - that worked pretty well but recently I've purchased a Cooler Master Ultra X3. Such a simple design - a nice looking bit of drilled aluminum (thin enough that if you don't rest your hands on the laptop when typing it does wobble annoyingly) with rubber bits to stop sliding. Added to that it has a USB powered (with pass thru port) fan system - 3 fans with a volume / speed control so you can choose how much air blowing is required. This works well because the fans can be adjusted so they are quieter than the laptops but they provide enough cooling to stop the laptop kicking into take off mode when the going gets tough. What's more the fans are mounted on the drilled holes on the aluminium sheet meaning they can be positioned to blow air directly at those areas of the laptop that heat up (along with some decent holes drilled in the case to let air in) this is a great solution.

Still, the laptop does heat up a bit though - from day one the processor has reported 51c on both cores as a normal temperature (that's using Speedfan which seems to report a little higher than most other products for some reason), whilst at boot the graphics card sits at 61c.

Delving inside has revealed those silly stick on thermal pads between the graphics processors and the heat sink. Waste of time, off they come and in goes some decent thermal paste (MX2, I've lost my Arctic Silver somewhere). No change in temperature there on boot, however, what I can immediately see is that heat transfer has improved because the temp does not rise much at all - I can also see that it is the GPU temp that is causing the fan to go into take off mode.

Still not happy though - the thermal pads were physically thicker than the paste and inspection shows that the gap between GPU chips and the heatsink is only just being bridged by the paste (caused by stand offs on the heat sink) - this also shows what a poor job the thermal pads are doing as one of the subsidiary chips had no contact at all.

Shims required but oh boy, they would be around £5 each for a 1cm x 1cm piece of copper from ebay. However, a 10cm x 10cm piece of copper (.9mm) was £3.99 via an ebay shop, a bit of elbow grease required and a new hacksaw blade. End result is I've now removed all of the thermal pads (GPU had 3, 2 chips next to the processor had 1 each and the south bridge had one - the CPU didn't) and replaced with custom sized copper shims and MX2 paste (I cheated and only cut one for the chips next to the CPU).

Was a good opportunity too to clean off the solidified cheap rubbish from the CPU and carefully dust everything.

The end result is that now the GPU temperature is 42c (around 39 on boot) and I haven't yet seen it approach the previous 61 degrees starting point), processor temperature continues to be around the same but falls more quickly whilst the fan simply does not kick into take off mode at all - all in all a good result. Interestingly the overall internal temperature has dropped - the hard drive not runs 2 degrees less than it did and the case over the cooling fan and hard disk bay noticeably doesn't get hot as it used to.

Any more to do? There isn't supposed to be a shim on the CPU (just paste when I rummaged) but if I ever take it apart again I'll be trying to wedge one in there (hoping I'll discover a cheap source of something less that .9mm by then) because I'm pretty sure the CPU should have a better connection - I think with nothing to start with wedging .9mm of shim in there would be a bit drastic but I think there is scope for improving the CPU temperature.