Windows XP 64-Bit Preview: First Look at Athlon 64 Performance

The 32-bit vs. 64-bit results in Sandra are very interesting.  Even in this pre-release version of XP64, the Athlon 64 CPU and Memory Performance is higher than in 32-bit Windows XP.  Mips, which is based on ALU tests, is more than 10% faster, and Integer and Float tests in the Sandra 2004 Multimedia benchmark is 1% to 6% faster.  The only area without increased performance in 64-bit is the mflops component of the Arithmetic benchmark.  If we look closer, this benchmark is a combination FPU performance and iSSE2 performance.  While Floating Point increases some 11.6% in the move from XP to XP64 Preview, the Intel SSE2 results decrease by about the same amount.   The net result is virtually no change in the composite mflops.  We do not know if this is because Intel SSE2 is penalized by 64-bit operation or whether XP64 and/or Sandra 2004 64-bit benchmark require some optimizations for 64-bit performance.