Windows XP 2.75 GB RAM VS Windows Vista 4.00 GB RAM

[AceNightBlade]

I need to decide either to go Vista or XP.
Vista sees all 4 GB of my RAM, but as everyone knows, is a major memory hog.
XP only sees 2.75 GB of my RAM, but the OS is faster in general.

So, would vista run a bit faster with the extra RAM? I think in XP the bios reserves 1 GB and my video card reserves 256mb. Or at least thats what i've heard.
1.25 GB difference is kinda big especially for vista.

I've dual booted between them, but i want to stick with the faster OS.
Or maybe i can go with the 64 bit edition of XP. But then again there are compatibility issues.

Whats the OS you guys typically use at the LANs?
I want to use the one fastest for gaming.

Help me decide


~SPECS~
Intel Core 2 Quad Q6600 @ 2.4 Ghz    ->   Thermaltake V1 CPU Cooler
4 GB OCZ 800 Mhz RAM
Thermaltake 850w PSU
400 GB Hard Drive
nVidia nForce 780i SLI Motherboard
ATI HD 2600 XT 256mb
Cooler Master HAF 932 Case

[Modious]

I'd Grab Windows XP 64bit. It may have its issues but, Vista will probably just drag you down. Read up on PAE (Physical Address Extension) That should help you if you dont want to switch and stick with 32-bit.

[Action]

Might want to dual boot windows XP and Windows 7 Beta.  I heard Windows 7 is actually faster than XP for gaming.