I created a Windows 7 Enterprise 32-bit VM and a 64-bit VM.  I wanted to see which provides better performance.  Since VMware Tools aren’t ready I treaded lightly with my tests.  Other caveats:  VMware Fusion does not support Windows 7 yet.  These are PassMark tests and not real world tests.  I didn’t run endless tests – just a handful.  Your milage may vary (greatly!).  The performance is based on Win7 32-bit (32/32).  The results are:

Win7 64-bit Running PassMark 65-bit (64/64)

29% faster on CPU
178% faster on 2D graphics
36% faster on Memory
19% slower on disk operations

Win7 64-bit Running PassMark 32-bit (64/32)

11% faster on CPU
13% faster on 2D graphics
11% faster on Memory
35% faster on disk operations

I was perplexed on the 64/64 disk performance being slower than the baseline and re-ran the test a handful of times and got similar results.  64/64 2D graphic results were impressive but not a driving factor for me.  For CPU and Memory 64/64 showed a nice bump over 32/32 and even 64/32.  In the end, the issue of whether to move to 64-bit Windows 7 is moot for me – the driver I need is only available in 32-bit so I’ll be running 32/32.

Here are all the versions used in the testing:

VMware Fusion Version 2.0.5 (173382)
Microsoft Windows 7 Enterprise [Version 6.1.7600]
VMware Tools for Windows Version 7.9.6. build-173382
PassMark PerformanceTest 6.1 (1010) WIN32
PassMark PerformanceTest 6.1 (1018) WIN64