If you go shopping for sub-$100 processors right now, you'll be faced with two main contenders: Core 2-based Intel chips and AMD Athlon X2s. The Athlons typically have higher clock speeds for the price, but their Intel rivals often perform better. Why?
Real World Technologies has put together an in-depth comparison of the Athlon and Core 2 designs. Kanter compared a 2.8GHz Athlon 64 FX-62 with a 2.93GHz Core 2 Extreme X6800 in four games, and he found that the Core 2 split instructions into more ?ops than the Athlon, and—unsurprisingly—processed a greater number of instructions per clock (around 5-10% more). Branch prediction tests showed "vastly" greater accuracy on the Intel front, with "about 50% fewer mispredicted branches per instruction retired." Kanter does nonetheless point out that branch-prediction accuracy was comfortably above 90% for both chips. Finally, on the cache front, Kanter found that AMD had a more effective L1 cache, while Intel's L2 cache had "about 50% fewer misses per instruction retired."