It's a big start.

The only DXi synth that is known to work with 64-bit versions of Windows is the Coyote Forte, available through PG Music. You can try it free for 30 days but must pay after that.

I have the same problem. As I cannot presently afford Forte, I am using an outboard hardware synth instead. It is a Roland JV-1010. Although it is several years old, it sounds great and, being hardware, has no latency (delay between the time a "Note On" command is sent and when the note is heard). However, you have an extremely powerful machine with lots of memory. Latency from a soft synth should not be much of an issue.

So your choices are pretty much Microsoft GS Wavetable, Coyote Forte, or hardware synth. Any General MIDI (GM) synth, such as an inexpensive Yamaha or Casio keyboard with MIDI or USB ports, could be used. (You would need an adapter for a standard MIDI connection.) Users here are recommending the Ketron SD-2 as the best GM synth they've ever heard. I believe that it is available through PG and from username "Mac".

Hope this helps.

R.

"My primary musical instrument is the personal computer."