Windows 7: 6 GB Installed (3 GB usable)

When you bought/ordered this sytem did you ask for more RAM? Because that is an odd configuration considering that the system is locking (reserving) 3gig of RAM!

Anyway what you could try to do is remove the 2 1gig stick and see if the system will give you 4gig of usable RAM. If that works, you might give Dell a call and ask why the weird setup cause is this case..... more is less

No, I didn't ask for more RAM; I bought it at Staples, and that's just how much came with it. On my way to work right now, but I'll try taking out the 2x1 GB sticks.

Okey dokey so I, heh, got curious and I took the 2x1-GB sticks out. It works.

I don't understand; in the documentation diagram, from right to left, the slots are 2, 4, 1, and 3. The way it was in there to begin with, I had a 2-GB stick in slots 2 and 1, and the 1-GB sticks were in slots 3 and 4. Which gave me 3 GB usable. I moved the sticks in slots 1 and 4, so that in slots 2 and 4 were the 2x2-GB sticks and in slots 1 and 3 were the 2x1-GB sticks, which is what gave me 4GB usable RAM. Is it just that first set of light and dark RAM slots that the CPU is capable of detecting? Or, because it detects them all, is it merely detected the first two sticks that it came to in the order?

Still showing 4096 total/4088 available in BIOS, System Resources is detecting all 4096 and that 9 MB is system reserved, which gives me 4087 available, minus the 1.4-ish GB that the system is using. Upped my RAM User Index to 7.2; it was at 5.9 with 3 GB of RAM.

The problem may have to do with the fact that you have two different stick densities (1gig and 2gig stick) - though this shouldn't be a problem if the sticks are correctly configured (installed) as designed by the board manufacturer. Most board vendors have rules for RAM placements based on unequal densities. This rule should be specified in the manual for the board. If this isn’t followed, you’ll run into problems.

These rules are the result of the design of the motherboard and or BIOS, and a BIOS update may or may not solve the problem.

The other problem could also be that all four memory slots are filled, again, some boards act strangely if all four memory slots are filled, and some will even require a drop in memory speed - 1600MHz to 1066MHz.

That's about right and that's where you want it to be. Right now your system is working correctly with the 4gig of memory installed and all of it available for use vs the 6gig you had installed but only having 3 available for use. In this case less equals more

Based on where the system was vs where it is now, I would leave it as it is now. Even though you have less memory installed, you have more available for use now.

Hope this helps.