Windows 7 maximum amount of supported system memory will go beyond the limits of Windows Vista. In this regard, the high-end edition of the upcoming Windows client will play nice with just a tad short of 200 GB of Random Access Memory. Windows 7 has been designed to work under normal parameters starting with as little as 1 GB of RAM, in order to fit onto cheap and resource-constrained netbooks. However, given proper hardware, namely if the mainboard can handle increased amounts of system memory, Windows 7 Ultimate is ready to swallow no less than 192 GB of  RAM. The Home Basic and Starter SKUs can manage up to 8 GB of RAM, with Home Premium taking the limit to 16 GB. The Professional, Enterprise and Ultimate versions of Windows 7 will support as much as 192 GB of RAM.

Source:→ Softpedia