Severely underperforming system, CPU Main Suspect

October, about 2 years ago, I purchased a new rig in preparation for the Left 4 Dead release.

ATI Radeon 4850 1GB VRAM
C2D E8500 3,16GHz
4GB 800MHz DDR2 RAM
Vista Home Premium 64 bit
2x Samsung 500GB 7200RPM HDDs
630W PSU, not sure which brand.
Biostar T-Power I45

The first couple of months it performed perfectly. With everything maxed out on a resolution of 1680x1050 with 8x AA activated, I never dropped below 60 FPS in games such as Left 4 Dead, Team Fortress 2, Far Cry 2 (no AA), Fallout 3, Warhammer: Age of Reckoning. Now I don't remember exactly what happend, but I started getting very low FPS in WAR at first. Averaging 30-45 instead of 60-100 regardless of settings. The FPS in TF2 dropped into 30s even on minimum settings which is funny because not even my old 7600GS did that.

I ignored it at first but eventually brought it in for repair in the shop. They took a quick look, charged 30€ and claimed that nothing was wrong with it, but they recommended a reformat... And so I did, but the reformat did nothing. Believing my graphics card might've been broken as it had a few problems with the fan so I bought a XFX ATI HD4890 on the release. It obviously increased the performance in 3Dmark and in a few GPU intensive games such as Crysis but I still had these FPS drops. To this date, I've reformatted 3 times. Most recent one was a few months ago.

My computer seems to struggle with the unreal and source engine leading me to believe it's a CPU issue. I can't even keep a constant 60 FPS in the ut2k4 engine game "Killing Floor" when there's action going on.

My vantage score was about 9k. 10800 GPU score and 6400 CPU score. 3Dmark06 score is about 14500. Unfortunately can't remember what I got in the shader model 2 and shader model 3 scores but I recall it was 2900 CPU.

Feels like I've tried everything but suggestions are always welcome.

It could be a dodgy power supply or your CPU may be overheating if the airflow in the case is not sufficient, and underclocking itself to prevent damage.

Source and Unreal should run well on Duos, but both engines show major benifit with quads, so it might be your duo showing its age...

Ultra Settings, 0x AA.

In the short range benchmark with my 4890 I only get 35 with 8x AA and about 50 without.

If your machine was performing well at first and then started performing poorly later while doing the exact same things, I'd first suspect viruses/malware, then overheating and throttling parts, and then OS/software errors (hung tasks, massive amounts of resident applications, "registry rot" etc.) You reformatted your HDD several times and nothing changed, so I doubt it is a software error or malware. You replaced your GPU and got the same behavior as before, so it looks like that wasn't the problem. Your CPU temps are appropriate, so it isn't likely throttling and sapping performance.

The only thing I can think of is maybe you have run into a GPU driver performance regression. You went from an ATi R7xx card to another, so the driver stayed the same. So did your relative performance- the 4890 is faster than the 4850 but performance in those games is still poorer compared to a competing NVIDIA card. You could test this hypothesis by either borrowing your buddy's NVIDIA card and seeing if performance increases or by going back to a Catalyst driver revision you ran on the 4850 when it still ran well and seeing if your performance goes up.

He is referring to killing floor which uses the old unreal 2004 engine, it's single threaded.

OP I wouldn't worry about lag in Killing Floor, I've played that game and it's kind of buggy, I get random lag spikes on a 3.5Ghz Athlon II.

It's a long stretch, but you may have AA/AF settings in CCC over riding your in game settings. This would definately cause performance problems in some games.

Hi
I dont know but it could be the drivers. y dont u use the drivers u used then when u bought your computer. Also maybe it could be the psu. u can use another psu to test it, y dont u swap your psu with your frriend for few days and test it. apart from that i think if u reinstall your windows that can help. hope i helped