Anyone who knows how to use a screwdriver can install it I guess.

The hardest part is getting the stock hsf off. Just make sure you first heat up the card using a 3d app. for a while and the heatsink will separate from the gpu quite easily.

That's a small passive cooler on that HIS 4670. With an Arctic S2 you get about twice the amount of cooling surface and ram heatsinks...

I kept getting crashes also when oc-ing my gigabyte 4670, but disabling VPU Recover solved that. Zero crashes now when oc-ed.