Alright i really love my new ati HD 4870, it runs cod4 and crysis great.

First of all tell me if my performance sounds accurate, Im running XP sp2 and my system contains:

Q6600 3.77 ghz 1880 fsb 60c peak
3328 mb corsair ddr2 930 mhz oc 5-5-5-13
Asus Maximus Formula (470 fsb)
HD 4870 stock 750/900 *sometimes* 790/1100?
X-fi xtrememusic
2x WD 150gb raptors raid0
320 gb seagate 7200.10 storage
PSU: Silverstone 750w <----- Makes loud buzzing noise under load??

3dmark06: @ 790/1100 mhz is 16,850
Crysis: Very high XP config @ 1600 x 1200 = 30 fps average on GPU fly-by
COD4: All max 1600x1200 4xaa 16xaf 90-125+ fps unless in heavy smoke (rare).


Alright now heres the odd ocing issue, if i manually set my clocks to 790/1100 most of the time it artifacts in Ati tool within seconds however there have been a few times where it wouldnt artifact at all.

Another thing, if i use the Auto tune feature in CCC it tests my clocks all the way up to 790//1100 mhz and finds it 100% stable, i have even tested this and ran Atitool during the auto tune and *found no artifacts* throughout the entire tune even when it was at 790/1100 mhz. However once autotune is finished, once the clocks set themselves if i run atitool again i get artifacts immediately.

I really dont understand what the hell is going on, i read somewhere that auto tune adjusts your voltages, maybe mine arnt sticking? Some help here.

Btw: card peaks at 62c with 40% fan speed.

Last I heard, ATItool doesn't officially support the HD 4xxx series yet and official Catalyst support for HD 4xxx series doesn't come until 8.7 (which is soon). Don't know if that would be part of the problem, but it's a possibility. As for your artifact problem, I'm not sure what to make of it. It is rather weird. I'd say just tone down the clocks by about 5 MHz a step and keep testing until you definitely get no artifacts in any situation.

Also I don't like any automatic maximum clock setting tools. I think they're too risky. You could end up clocking to an unsafe speed unknowingly and crashing your machine. At least that's happened to me with ATItool.

My experience with the Catalyst Auto Tune have been very successful, and I happen to like it. It overclocks the card well enough without being dangerous and thats what I look for personally. Mine got to 780/1065 and I stoped it, but the memory would have probably reached 1100 if I didnt.

Under 780/1065 I have ran several different tools and games and only had issues once, with Mass Effect. Sometimes the driver would stop responding, or the screen will fill with dragging textures. Other than that, running 3Dmark Vantage 5 times in a row, and AoC for countless hours ive had no problems at all, and 750W is well more than enough for your system so I wouldnt put blame on that (however I dont know about that hum). If its just ATITool showing artifacts then I wouldnt worry about it, since as math said ATITool hasnt been updated offically.