If you have an Athlon or Xeon processor, go into usr/src/test/sysperf, do make, and the resulting /tmp/mem1 program will probably give interesting results, which you can then post to the kernel mailing list. A caveat from Matt Dillon:

“Note however that you have to manually edit which copy tests it does since it bus fault if you try to run the XMM (SSE2) test on a machine without SSE2 :-)”