At least 512 to run a top end DAW ( including Tracktion, FL, Sonar, etc ). You'll want even a little more than that if you plan on using Vst synths or effects. I use 1024 on my PC ( Athlon 2400 - 2.0 Ghz Procesor ) and 768 on the laptop ( P4 2.8 Ghz ). Sometimes the Laptop strains when I run more than a couple of high end Vst effects and instruments.

BTW, I saw your post about the drum machine, and with that in mind, I have a couple of freeware sf2 ( soundfont ) and analog vst drum kits that might make you happier than the kits on your arranger. Let me know and I'll send 'em to you. You could use them in FL, Tracktion, or any other app that supports VST or DXi.


AJ