NOT the best mod,BUT EFFECTIVE

After reading this artical
Here
I decided to put a fan on the opposite side of my comp Its placed right behind the CPU

I know it doesn't look the best ,but hey its under the desk...so who cares.
It does a nice job of sucking out the heat from behind the mobo and it did make a 5*deg diff in CPU temps

Not bad for 20 mins work and an xtra fan laying around
Might put one behind my Northbridge

nice work. ive been doing that to a few pc's over the last few years but sucking air in. socket temps reduce heaps and core temps reduce a lil bit. putting silicon grease in the socket helps the heat transfer a lil bit aswell.
the next stage is this, as applied to a 6600gt:

it benefits gpu's even more than cpu's cos you are cooling the chip via the actual pins of the ic, not just the socket, so there's much better thermal conductivity.
the danger of fitting a heatsink to the rear is great. you must use silicon grease or ceramique and you must make sure the heatsink wont short anything. measure clearances using fibre washers or silicon heat transfer pads or other insulators in the corners of heatsink. once clearances are checked, remove & fill with compound. the cooling power is much greater with the heatsink on gpu's, the biggest rear fan couldnt compare to a slow fan on rear heatsink for gpus.
it is only a little better on cpu's however - it just means a slower fan does the same job.

that gpu mod i wouldnt want to risk shorting things. o.O that is just absolutely crazy... imagine if it shorts the gpu and the gpu shorts the mobo. now imagine if that was a 8800gtx. Yeah....

the upper mod looks ghetto and i like it. haha.

imagine the shorts that can happen in a pc case if anything isnt done properly! that being said, although ive done a few of the above mods to gpu & cpu, which are still working perfect after years of use, no-one should attempt it if they dont know 100% what they are doing.

attempt to recreate at own risk.