I had the same problem in version 3.4.3: one of the four CPU cores was 100% busy (i.e. 25% overall CPU usage). The problem is fixed in version 3.4.4.
Thanks!
Okay.. hopefully those other bugs don't spoil the fun (BSOD's when changing settings of a mounted RAM disk or unmounting a RAM disk, and random data-loss, even with "Save to Disk" enabled... under Windows 7 x64 Ultimate).
I'll report back whenever i found the time (and guts) to test this.