Really? the only instructions that I remember the AMDs never had in comparison to recent Intel processors are some very specific SSE3 and the SSSE instructions. I think it's just the recent Intel processors are more optimized than current AMD offerings, since it seems that the Core2Duo's are a brand new architecture while the latest from AMD's (Seems to be) still further optimizations from their product that's made from 1999.
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Current PC specs :
AsRock 945GCM-S
Pentium Dual Core E5200 @ 2912Mhz (233x12.5)
Palit Radeon 4850 Sonic 512MB gDDR3
2x2048MB Kingston DDR2 800Mhz RAM