You seem to be one of the lucky few.
My system is similar to yours.
i5-2500
12GB
GTX 570 i average 40fps, v-sync off, latest drivers, everything on low 1x etc and ive seen it drop to 20-30fps before...
others with more powerful cards than ours e.g. GTX 670, 590 have had problems getting decent frames.
wanna tell us your secret?