Again, thanks for all the help! I've decided not to ugrade my card just yet. Some of you (and 2 friends of mine) advised me not to. So it has been cleaned and has played great at the highest resolution. The 'stress' has been very limited, and I'll definitely try to lower the resolution a bit and see if it'll help as well
I have one of these and it's very quiet. http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/25111-sapphire-radeon-hd-5870-vapor-x-1gb-review.html
It's the simplest program to use. All he needs to do is change the fan control slider.
and cook his card? the fan is running at that speed for a reason.
Gelmir - a couple of case fans maybe all you need.
A standard PC will have fans on the CPU, graphics card and in the PSU (power supply). Those fans will be thermally controlled and will speed up as things get hotter. *Normal* temps when gaming should be roughly 55c on the CPU and 85c on the graphics card though lower is always better. A free program like HWinfo32 can tell you what your temps are.
A *gaming PC* will typically have 2 extra fans to create better airflow in the case and will drop overall temps by 10-20c and everything will benefit including hard drives. More fans wont make your PC noisier as the other fans won't have to spin as fast to keep things cool and it's *fan speed* that creates the noise. For example a 8cm fan that spins at 2000rpm is going to be a lot louder than 12cm spinning at 1200rpm.
I have a fan at the front bottom of the case in front of the hard drives drawing air into the case and a fan on the back behind the CPU svcking air out - 2x 12cm fans running at 800-1000rpm - very quiet and my GPU and CPU fans tick over at about 40-50%.
Someplace like this http://www.quietpc.com/gb-en-gbp/home can sell you the fans and even an aftermarket cooler for your graphics card if you should feel like it but I would do the case fans first as its easiest and makes a real difference.