Medved Trader will run on Vista SP2 or higher (so no XP) 32 or 64 bit, so that is the bare minimum. As for recommended, well, certainly not Vista. We recommend Windows 7 or Windows 10, 64 bit with at least 8 Gig of RAM. Also note - A very common performance issue is due to security software such as Microsoft Security Essentials and Windows Defender. If using either of those, make sure to exclude MT: http://forums.medvedtrader.com/topic/281-problem-microsoft-security-essentials-windows-defender/