Vista - Sluggish performance in Vista64

I have been battling a problem with my new build for almost 3 months. My rig:
Gigabyte EP45-UD3R
Core2Quad Q6600
G.Skill DDR2-800 2x2GB
Geforce 6800 GT
PC&P Silencer 500W
WD Black 1 TB
Vista Home Premium 64-bit

My performance is terrible! This is my first experience with vista. My pc runs sluggishly, sims 2 game crashes at startup, my other 2 games (half life 2, left 4 dead) are very choppy and unplayable. Browsing playlist in iTunes with cover art displayed is choppy and slow (unusable, i have to turn the cover art off).

If I take out 1 of my sticks of RAM it seems fine. If i load XP, it seems fine, even with both sticks.

I have ran memtest on my ram, tried my ram in all the slots, ran prime 95 for hours with no errors, ran diagnostics on my hdds, rma'd my motherboard (they returned it saying nothing was wrong with it), purchased a new motherboard (asus p5q), tried 2 other kinds of RAM, updated all of my drivers, reinstalled vista a billion times, and NOTHING has worked.

The only thing left to replace is my cpu and before I go through that hassle, I just want to exhaust the last avenue, since the problem is only evident in vista with all my memory sticks installed.

Does vista not like my 6800 GT when I'm using all my RAM? It seems silly that its a hardware issue considering things work fine in XP and considering all my other hardware seems ok. Any insight?

your video card is a bit of a clunker. it was manufactured wayyyy back in 2004.that is probably what is slowing your system. especially if you have all of vista's eye candy on.

yeah it is old, i know that. i am going to upgrade it soon but didn't at first because its supposed to work fine with vista.

in fact, it does work fine in vista when i use just 1 stick of memory. i'm trying to understand why more memory makes my performance suck.

are the two memory modules EXACTLY identical?

I'm not sure how to verify that. I can tell you I purchased them in a kit. I also purchased OCZ 1066 memory in a kit, and tried my friend's SLI memory (kit also) and observe the same behavior each time. Find it hard to believe 3 different kits all have mismatched sticks.

for anyone who may have the same problem. i fixed the problem by replacing my video card. my card is not broken, it works fine in other systems. apparently, there's something with vista and "more memory" that was causing my performance hiccups. i'm curious to know what the issue is, but i've seen at least 2 other forum posts of the same issue with the 6800 gt card and larger amounts of RAM.

My card ran fine in XP with 4 gb of RAM, but in vista, it didn't like 4 gb and ran better with 2 gb.

well i can tell you one thing about it, that the card doesn't work on and that is an almost 0 compatibility with a 64 bit system there is your issue right their with your graphis your system was slugish because it was using the cpu or onboard graphics to generate the images rather than the graphics card and probably causing memory conflicts as well or some other mishap within your system.

thier is no getting around it though if you want better performance from a home built system do a little research into what you are buying for it first make sure everything is compatable before fitting it, may seem like a drag spending some time that way but the upshot is alot less time trying to solve problems.

glad to hear you got is sorted though and do remember everyone when building a 64 bit system their is alot of hardware out their that is not compatable with 64 bit

I did plenty of research and went to both nvidia site and microsoft to check compatibility of that card with vista64.

The card ran fine with vista64 on 3 different motherboards as long as I limited the system RAM under 4 GB. There is no doubt a compatibility issue, although I question if lack of research is a good explanation, considering if I had just chose to to instal 2x1GB of RAM I would have never found this "incompatibility" in the first place.

Being that I like to support my claims:
http://www.microsoft.com/windows/com...20GT&os=64-bit

Yeah, just posted almost the exact same thing in 6800GT/Vista64/6gb RAM issue. Definitely compatible. Nvidia even offers a vista 64 driver that supports the 6800GT.

The lack of research response is ridiculous, unless you really think my mobo/cpu was capable of rendering aero at 1920x1200.