i have a radeon hd 7870, 4-core with 4,2 GhZ, 8BG Ram and Win7 64 bit
I bought this game yesterday. i have deinstalled and installed it 3 times! by Steam in the properties>Start Options i filled this: -nosplash -noPause -maxMem=8192 cpuCount=4 -nologs
i got the lags also in the menu and in the user interface. i set all options on very low but no diferrent to high.
GPU_MaxFramesAhead=1;
GPU_DetectedFramesAhead=1;
sceneComplexity=500000;
shadowZDistance=100;
viewDistance=1600;
preferredObjevtViewDistance=1600;
Sorry for my worse English :)