Only seeing 2 out of 4 GiB of ram

I've read all of the "I'm not seeing all of the 4GiB of ram" articles and
none of them seem to match my problem. I have 2 sticks of 2GiB ram (Mushkin)
installed in dual-channel. The bios on my mainboard (EVGA) recognizes all
4GiB of it, so that isn't the problem. I'm running SLI graphics cards with
512MiB each. When I look at system info, it says I only have 2GiB installed.

I just don't see how 4GiB turns into 2GiB even with the graphics card ram
subtracted out. I would expect to see around 3.3 to 3.5 GiB.

Thanks for looking,
Jason