Guide step by step:
Windows XP:
1. Right-click My Computer and select Properties. The System Properties dialog box will appear.
2. Click the Advanced tab.
3. In the Startup and Recovery area, click Settings. The Startup and Recovery dialog box will appear.
4. In the System startup area, click Edit. This will open the Windows boot.ini file in Notepad.
5. In the [Operating Systems] section, add the following switches to the end of the startup line that includes the /fastdetect switch: /3GB
IMPORTANT: If you notice a significant FPS loss, enter the following to the end of startup line:
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /fastdetect
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP with 3GB switch" /fastdetect /3GB
IMPORTANT!!!: If you notice a significant FPS loss, enter the following to the end of startup line after /3GB:
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP with 3GB switch" /fastdetect /3GB /userva=2560
My note: there is a space between /3GB and /userva=2560
6. Save the changes and close Notepad.
7. Click OK two times to close the open dialog boxes, and then restart the computer for the change to take effect. You will be able to choose the original version in case the 3GB switch fails during start-up.
Windows Vista, Windows 7
1. Open command prompt with Adminitrator rights. To do this, go to Programs, Accessories, right-click on Command Prompt and select "Run as Administrator."
My note: make sure you are in system32 directory when the command prompt shows up. If not, direct it to C:/Windows/system32
If you can't direct the console to the right directory, go to C:/Windows/system32 and run cmd.exe (select "Run as Administrator.")
2. Enter the following at the prompt and press enter:
bcdedit.exe /set IncreaseUserVA 3072
My note: there is no space between the slash and set.
IMPORTANT: If you notice a significant FPS loss, open the cmd.exe again and enter the following:
bcdedit.exe /set IncreaseUserVA 2560
3. Close the prompt and restart the computer.
A me ora va da Dio anche cliff , che prima era a scatti , ma a scatti davvero !!
Motherboard Asus Rampage formula Intel Socket 775 Core™2 Quad/Core™2. Chipset: Intel X48. Processor : Intel Core2 Quad Q6600 2.40 Ghz overclocked to 3.30 Ghz. RAM : 4 Gb 800 Mhz DDR2. Storage : windows 7 in samsung 128 Gb SSD and 1.5 Tb whit 2 hard disks. Audio : SupremeFX II . Video card : Nvidia GTX 660 2048 Mb gddr5 PCIe 2.0
lo reinstallo e lo tengo lì intanto!! Tu tienici aggiornati 
