The question is “How can I enable PAE on Windows 7 (32-bit) to support more than 3.5 GB of RAM” and the answer is type the command prompt “bcdedit /set [{ID}] pae ForceEnable”.
But, probably the question is worthy to be rephrased how to enable and be able to use more than 3.5 (or 3.25) GB of RAM on W7 32 bits system.
I tried PAE in 2 different Desktop mainboards with identical systems: Intel® Desktop Board D945GNT with a Intel® Pentium® D Processor 3.4GHZ and 3.00GB usable Ram, and Intel® Desktop Board DG41WV with Intel® E7500 2.93GHZ and 3.25GB usable Ram. Both 64 bits capable and 4GB Ram.
The 2 systems enabled PAE; then, using the procedure indicated in http://www.jensscheffler.de/using-gavotte-ramdisk-in-windows-7 I installed Gavotte Ram disk and recovered 16MB Ram (nothing) on the first system, but recovered the entire 775MB unused for the second one.
So, in the Ram disk of the second system, I assigned a movable pagesys file to it, from 16MB to 700MB, and a movable pagesys of 16MB to 3300MB on a partition of a different physical disk of the system.
I proved 2 facts:
1. The systems preferred the Ram swap file over the one in the hard disk. I saw it moving, growing and shrinking.
2. Benchmark with PC Pitstop (image attached in http://www.pablomolina.net/bench700.png) shows great improvement in system disk speed, and the system runs quite faster. In the bench I compared a 700 MB page file in the Ram disk with a 700MB page file in another partition of the same system drive.!
You need to set the system to clean page file at shutdown with Microsoft kb/314834 procedure.
For me, PAE makes sense on a 32 bit system, and works. I won´t go for the 64 bits system as I use Windows professionally and accumulated 450 programs over years, which will take me months to reinstall.