Maximum memory for Windows NT

"Windows NT detects up to 4 gigabytes (GB) of RAM, but if you are using a computer with more than 64 megabytes (MB) of RAM, Windows NT may detect only up to 64 MB. This behavior is based on how the BIOS returns the amount of memory to Windows NT. Even though the BIOS may correctly display memory above 64 MB, it may not pass this information correctly to Windows NT."

http://tinyurl.com/1r0v

4gb of physical ram
2gb virtual memory (3gb on some versions)