We had an old Windows XP server running a Filemaker database on a 2.6 GHz Intel CPU, but that server died. It's been replaced by a box with two 2.4 GHz Xeon CPUs and 5 GB of RAM that's running Ubuntu 11.04 natively, and Windows is running as a VirtualBox guest. 2GB of RAM has been dedicated to the Windows guest.
Of course, these old Xeon CPUs don't have the VT-x extensions, so I wouldn't expect to be able to add CPUs to the VirtualBox guest, but the Filemaker database is running at least 2-3x slower than it did on the old server. I would expect that utilizing one 2.4GHz CPU out of four available shouldn't result in such an astounding difference.
I would also like to be able to continue using this setup, since it would also mean we'd be able to remove our Linux server from the rack, which is running on even slower hardware (not that the system requirements are high for its job though).
So my question is: Why is this so slow? Is there anything I can do to change the situation? Or should I just give up now and find more suitable hardware?
Please note: I understand that the "new" machine should be about 1% slower in theory, so please don't tell me this "should" be fine. I need more concrete answers (as in, "I've tried this before and you should do X") since in the real world, it appears to be about 50% slower. I'm about to blame "virtual" CPUs to multithreading on single core processors, and possibly the difference in CPU architecture between Xeon and Pentium 4 CPUs.