4850 load problems

[R4DK0]

Hello all and thank you for your time!

I am expiriencing low fps drops in games such is Counter Strike : Source.
It is dropping from 140 to 30 and it is really annoying.
So; Ive tryed Riva Tuner, and I saw that is 25% GPU usage during playing.
Ive tryed ATiTool, and it is okay ~98% usage. Ive redownloaded newest drivers from ati official website. I tryed manually setting the clock from default 625/993 to 630/1000 and the difference is maybe in a few fps. Im running Crysis and Prototype normal, its playable fps, so could it be that is my CPU or anything else is bottlenecking it or is it something else?
If I try all settings to minimum its little difference

My pc
Intel E6300 1.86Ghz @ 2.8Ghz 1600FSB OC, 2Mb L2
Asus P5K-E Wifi/AP Edition
Ati 4850 512 Mb
4Gb 800Mhz RAM
Seagate 11 series of disk, 640Gb 32Mb cache for playing
1920x1200 resolution

Temps are not a problem CPU below 50°C at prime95 and gpu also over Ati tool

So is there anything to force the GPU to work at atleast 80% so I have lowest FPS around 60? Should I switch

Would it be better to switch to 4890 1Gb or Q9550? Or maybe a SSD would help? Cause there is a lot of tiny files as I know in that game

[Chickenfeed]

Given CS:S is still using the oldest of the source engines ( DOD was updated, TF2 and L4D both use new ones ect ) it is still very cpu limited. A better gpu couldn't hurt but if your remotely competitive ( eg want to have 100tick fps ) then having an optimized config and a fast cpu clock will do more than upgrading the video card.

Now when are you getting these drops? If it is random when there is little stress in the scene ( eg not during larger fire fights ) then I'd assume it is a driver issue ( I see you've mentioned installing the newest ones but it couldn't hurt to do a uninstall / reinstall and properly clean residual files ; I'll let you figure out how to do this ). If you are getting these drops during the more intensive action then I'd guess 1 of 2 things. You are either running too much AA and / or are playing in high player count servers ( I never play in larger than 10v10, usually 8v8 tops )

As far as an SSD, with a source based game out side of load times, the benefit is very small ( and even then a slower clocked cpu and a ssd will still load slower than a highly clocked cpu and lets say a high performance 7200 drive ; I based this off the fact my friend has an SSD in his older AMD system which is at stock ) Of the games I"ve ran MMOs and FPS games with high levels of LOD ( Crysis, ARMA II ect ) benefit most from a SSD ( source uses very light LOD so there isn't much required in the way of file through put after map load )

[R4DK0]

Well Ive reinstalled the OS, Win XP (love the design, simple and yet effective). Ofc I already tryed unistalling it first then installing new ones. Ill probably buy Intel Q9550 2.8Ghz 1333FSB 12Mb L2, and I get drops not consistive, and there could be another issue, my motherboard or at least the audio thingy, because I emit noise over the microphone, if I reopen the game/program (Skype) its okay. So I will keep my current graphics and disks and buy a better CPU, cause its olddd.

Thank you for your time Chickenfeed
Thanks all!