I'm using a Presonus Firestudio Project on Vista 32-Bit, with the Cubase LE 4.0 software that came with it. I have the max RAM you can cram into a 32-bit system with a quad core processor.
The only issues I had with it were some odd pauses in the middle of audio playback (didn't appear to be in the actual recording). I fixed it by shutting down anything and everything that wasn't essential to Windows/Cubase/the firestudio.
So kill your anti-virus, network connections, widgets...I typically go into the Task manager and start killing unneeded processes.
If your not sure about killing processes you can usually google them and find out what they are, just dont randomly kill them or your in for a good crash.
Also you should use the ASIO audio drivers if you can, any decent recording interface should have them with its drivers. Windows audio drivers are a joke when it comes to audio delay.