Windows 7 - Performance Issue on new Gear, Help?

Hello everyone, Im hoping someone here has some advice on a performance issue...

i recently upgraded my computer, however for some reason im constantly seeing this message appear more fequently then it ever did before the upgrade..

Its asking me to disable my win 7 aero theme to improve performance, that recources are low etc.. however i recenltly upgrade from 4gb of ram to 8, and to a new video card..

System Specs:

HD Radeon 6870 Vapor-X (this is new just installed)
AMD Phenom II 955 black edition 3.2 Ghz quad core processor
Ripjaw Series 4 sticks of 2gb ram total 8GB (Recently installed two 4gb sticks)
ASUS M4A79XTD EVO AM3 AMD 790X ATX AMD Motherboard

no idea why i would even have this trouble...

under my Catalyst control center i unlocked the overdrive to do some overclocking but i never overclocked anything... when im not doing anything the GPU clock is 100mhz and the memory clock is 150mhz.. i just recently got off a game, Shogun2 took a quick look at it and the gpu clock was at about 900mhz and the memory clock was about 1000mhz if i remember correctly, i dont know if this helps anyone...

a friend told me i may have an issue where directx 9 was conflicting with directx 11.. because i just came off a dx9 card which was the hd radeon 4850 and just installed the new card 6870.. like dx9 and 11 are running at the same time or something...

can anyone offer any advice?

by the way, the only thing on the PC thats pretty old is the power source, i believe its 450watts, not sure if that could cause this issue however.

oh and the Video card requires 2 pcie slots, the power source only had 1... but the card came with male adapters to plug into existing female power slots from the power source so i did that.

if it's 450Watts Power Supply then i would strongly recommend to take out the card before the PSU create more problem for you and get a new and a good quality PSU at least a 550-600Watts for a 6870.

The Radeon 4850 is a DirectX 10.1 card, not DX 9.

Did you uninstall the AMD (ATI) drivers before swapping garphics cards? That's recommended, even though you're replacing one AMD card with another. (Re-install the drivers after the new card is in place.)

A 500W or higher power supply is recommended for a 6870. You don't say what sort of PSU your 450W unit is, but if it only has a single 6 pin PCI-E power connector, it may not be a high-end 450W one. (They're not all created equal.)

Hav you run a memory test on your upgraded system? If you mixed RAM from different manufacturers (or even ram of different specs from the same manufacturer), you might be having compatibility issues. If you replaced all the RAM, the new RAM could be defective. (That happens, even for highly reliable makers.)

The RAM is exactly the same, as for above this I did last night go to device manager and ininstall the drivers for my card and reinstall from the amd site

That's good, except I have no idea what the problem might be. I'm not at all sure thatn underpowered PSU would ever give the "low resources" error.

Have you performed a Windows Experience Index on the machine as it stands? I'd expect a high number (>7) for a 6870.

If I'm playing a game and the card isn't getting enough power, won't the process9r take over and try to do all of it.. causing this problem? Cause I had 4 FB of RAM in there and the same processor and a smaller card and never had this issue.. now that I add 4 more gigs of RAM and a new card I shouldn't be having this trouble ...

7.3 to 7.5 on everything

Personally I think your PSU needs to be upgraded to a good one of at LEAST 650W.
In the meantime, use a standard Windows theme, no Aero to see if you can get along with that.