Dx11 and Texture packs are wonderfull, congratulations.

Frame variatons are extremely worse achieving 23-46 fps with 1680x1050 in "Very High" on Dx11. Before was 49-65 on Dx9.

New Game locks ( BSOD Dx9 / Dx11) in multiplayer so I can kill him in the manager.
I already cleaned the "Temp" folder from "C:\Users\b\AppData\Local\" and the "Shaders" cache folder from the "C:\Users\b\Saved Games\Crysis2\". And reinstalled the AMD 11.6 Catalyst. Default options.

And our dear cheaters forevermore with the very old techniques as ever.

Mother G31M-ES2C
Intel Q9550
4Gb Ddr2 Kingston HyperX T1
Ati Hd5870
Corsair 750w Power
Win7 x64 Ultimate
All in stock clocks.

you should try running a boot up memtest

Thanks Deathxxxhippie.
I suppose my system is stable because it survived to a lot of specialized stress benchmarks of various softwares included Memtest+ boot and others. Otherwise the game didn't crash by this way in the 1.8 Patch.

The name of the problem is called Patch 1.9 !

Frame variatons are extremely worse achieving 23-46 fps with 1680x1050 in "Very High" on Dx11. Before was 49-65 on Dx9.

I have the same card or similar, same 'issue'. Its because the 5800 series was the first direct X 11 model it suffers a bit with tesselation. If you turn that down it will do a lot better. The 6000 series have twice the tesselation power, though almost the same power for everything else. Under directX 9 and 10, the card is fantastic, but it was their first card with directX 11 support, so we will probably have to wait for drivers to improve performance.