Step 1: Integration of the RAM above the 4 GB limit
Let's turn to implementation. There are a couple of different programs we can use. One of them is the paid version of RAM Disk Plus 10.1. It's very easy to use and reliable. A decent freeware alternative is Gavotte RAM Disk 1.04.
Step 2: Use the "unmanaged" memory as RAM disk
With one of these programs, you can use the memory that otherwise wouldn’t be addressable by a 32-bit operating system. Remember to enable the memory remapping function in your BIOS or nothing will happen.
Now we need to format the new drive. When creating the RAM disk, you can even use your "missing" RAM (the memory between the 3.25 GB used by Windows and the 4 GB actually installed), but only if the hardware is compatible. If this causes stability problems, you can try to leave 100 MB or so unused. With current hardware, though, you should be able to use the entire memory area. Don't forget to reboot Windows when you're done.
Step 3: Setting up the swap file
Now fill up the total available space on the RAM disk with the swap file, or at least 4 GB. For this test, we installed 12 GB RAM, so we use a 8 GB swap file. We select the RAM disk as a swap file directory and reboot Windows one more time. From now on, Windows will use all RAM above 4 GB as swap file and the hard drive gets to take a vacation.
Note: Be careful with sleep mode. It could pose a problem with this approach, so you might have to decide between performance and convenience.
Step 4: Transfer the temporary files to the RAM disk
Since we have 12 GB of RAM installed, we choose to use just 4 GB for the swap file and to use the remaining 4 GB for temporary files. This way, the temp files are written to the fast RAM disk instead of to the slow hard drive, and you also delete the unnecessary files automatically by turning off the PC. Web surfing can be accelerated in this way, simply by relocating the browser cache directories to the RAM disk.
However, we feel that most users can handle the 4 GB restriction. In normal daily life, this amount is sufficient for most tasks, short of bleeding-edge digital video editing, handling giant file archives, or the like. Enthusiasts will probably want to play around and see what amount is enough for their needs.