Kees Hoekzema wrote:

The problem with this test, and anands test too, is that in the mysql benchmark they use mysql's own benchmark. That benchmark does a shitload of inserts and selects, but not the kind you would use in a webpage for instance. I'm going to run them too, and probably get a whole lot different results with my own benchmark based on our website.

Last time I ran my own benchmark I tested a 32bits vs a 64bits mysql binary. MySQL's own benchmark gave the 64 bits version quite a lead, but in my testing the 32 bits was roughly 20% faster than the 64bits. I've tested it a couple of times and every time the 32 bits was in the lead up to 20%. Since than I lost my belief in mysql's benchmarks a bit ;).

The only benchmarks that matters to you are your own. Aside fron that, my benchmarks between 32 and 64 bit systems have shown that I get the best results on each system using code built for those specific architectures. I have 32 bit apps that were simply dragged and dropped into the 64 bit systems with some performance improvements. But the big improvements came when we recompiled our apps using new versions of GCC that supported the 64 bit architecture of the Opterons. For our numerically intensive applications, we saw over 70% improvements over 32 bit systems running at the same clock speed. But there was another cost that affected the throughput. The 64 bit compiled apps would use up more memory, so the memory that was just adequate to support the 32 bit apps would not be enough for 64 bit apps, and the subsequent swapping would make the apps run very slowly, as expected. I think that if you can rebuild your mysql binaries from source on the 64 bit system using the latest GCC compilers, you can gain huge increases in performance as well. eyc