my specs are:
AMD Phenom X4 955 @stock clock
8GB 1866mHz RAM
Sapphire Radeon 7870
ASUS M4A79XTD EVO mobo
2TB Seagate Barracuda HDD
OZC ZT series 750W supply
but somehow i can only run Far Cry 3 and GTA IV on medium settings to have it playable. And i cant even play GTA San Andreas because it is VERY laggy. But i should play Far Cry 3 on high settings with 70 FPS but now it runs high with 20 fps
Did you download the latest drivers from AMD's website?
Your cpu is bottlenecking your system. I have the same ram and GPU as you, but a FX-6300 cpu and asus M99X mobo and I run my games at mostly top settings. Battlefield 3 runs at Ultra just fine. (I keep anti-aliasing low though)
I have a phenom II x4 955 as well but I can run Far Cry 3 alright, with no lags whatsoever. I do not think the cpu is bottlenecking, especially to that degree where games will be laggy and unplayable.
And GTA IV is just HORRIBLY UNOPTIMIZED, terrible port job.
GTA IV PC port is atrocious, however, even with my 560Ti (similar performance to a 7770), I can get ~50 FPS on GTA 4 maxed out, and about 35 FPS on Far Cry 3 on high.
Your CPU is getting dumped on by GTA IV, that games loves the mhz and fast cores..
To get a steady time in GTA IV, a CPU at 4.5-5GHZ from the intel range is pretty much needed...... it is not your GPU.
i don't know man, I'm playin GTA IV on a 965 in combination with a 7850 and it runs just fine ôO