LOmac buddy, i recently replaced my E6750 with a E2140, OCed the E2140 to 2.67GHz.
I found out the gaming performance of E6750 and E2140 at same clocks is the same. I tested Crysis, Stalker, Oblivion and Gears.
Even the 3Dmark06 scores with E2140 were less by just 80 points( 40 in CPU Marks).