Configuring the /3GB functionality using BCDEdit is not a difficult task. You’ll need Administrator privileges, and an elevated command prompt. The command itself is actually very simple: BCDEDIT.EXE /Set IncreaseUserVa <value>. <Value> in this command represents the number of megabytes that a user-mode process can use. If you think of 1GB as 1024 MB (2^10) then to allow 3GB of memory we allot 3*1024 MB = 3072 MB. Thus our command becomes BCDEDIT.EXE /Set IncreaseUserVa 3072. We can tune this value as needed, just like we did when we combined /3GB and /USERVA in the boot.ini. To set /3GB /USERVA=2970, we would BCDEDIT.EXE /Set IncreaseUserVa 2970. Fairly straightforward, right?