If your 3dmark scores are about average then more then likely its your mods in Crysis2 , AFAIK the MalDoHD puts a lot more stress on systems due to the better textures and mods
Actually no it doesn't, I've noted a much higher frame rate increase since using MaldoHD myself. When Crysis 2 was pushed out, it wasn't very optimised, and still isn't. MaldoHD sort of fixes that.
Without MaldoHD on stock 7850 clocks, maxed out @ 1080p, average 45 FPS, while with MaldoHD on a stock 7850 I'm getting around 49-50.
Also, get rid of that auto clock and run at stock. Often those "auto clocks" put way too much voltage and can put the CPU under some strain, that might be causing your issues.