Official information on the 64-bit Beta can be found on the Microsoft site.
- Athlon64 or Opteron Processor
- 256MB RAM
- 1.5GB Hard disk space
- SVGA or better video card
- CD or DVD drive
- Keyboard and Mouse The download is large, so they are offering a CD if you would rather pay than wait.
If you want the best performance, you should look for 64-bit drivers for your hardware before you upgrade. 64-bit OS+32-bit drivers with 32-bit program will likely not run as fast as 32/32/32 on the 64-bit CPUs.
Good luck, and post your results if you try it.