I have a newer Dimension E520 from Dell that won’t recognize all of the RAM that I have installed. Per Dell, the system can handle 4GB of DDR2 Ram at 533MHz. It has a total of 4 paired Ram slots and it came loaded with 2GB; a 1GB stick in two of the slots with two open slots. I added 2 Kingston Technology 1GB PC5300 240-pin DDR2 DIMM Memory sticks. Per Kingston, these RAM sticks are compatible with PC5300 and PC4200 DDR2 memory slots and they will operate at 667MHz when used in PC5300 slots and 533MHz when used in PC4200 slots, I have PC4200 slots at 533MHz so they should work just fine. All Ram sticks are installed and paired properly. Also, the system has a 1066fsb. All 4GB of RAM are recognized by the Bios system boot menu but when I check the system info after Windows loads, it only lists 3.0GB of ram. I have been told that XP operates at a max of 3GB of Ram because it is a 32bit OS but I have also been told there is a way to change this with Bios settings. How do I get Windows to safely use ALL 4GB of the Ram I have installed??? Other info, my computer uses a Intel Core2 Duo E6400 processor @ 2.13GHz, I also have a ATI Radeon PCIe X1300 Pro with 256mb of on board memory. I really want to get the most out of my system. The System menu in Windows does say Physical Address Extension below where it lists the Ram so I am guessing that I don’t need to add /PSE to the boot.ini file.
