I just got a new PC that was compleatly built out of mostly low end cheap stuff which I had no choice in. Now I have to get it up tothe the level that I like with any PC. I have already got a new EVGA 8800GT SC so now I have 2 major things I want upgraded. I like to check before I buy so here it goes.

Right now I have 2GB of 667MHz non dual channel DDR2 RAM for my PC. I want to get some new stuff and its either I geta new pair of 1GB800MHz Dual Channel DDR2 RAM or I get a new set of 667MHz Dual Channel DDR2 RAM and am able to keep my old RAM because it operates at the same speeds. So basiclyis 4GB of 667MHz or 2GB of 800MHz better? I am really tired of getting the "Your computer is low on memory" windows pop up when I play Crysis so will faster RAM fix that at all or just more GB? These are my choices for the 800MHz DDR2 RAM and the 667MHz DDR2 RAM.

My CPU right now is an Intel Core2 Duo 6450 2.13Ghz. This isn't really cutting it for me with all the stuff that I do so I am looking at either the Q6600 2.4GHz Quad Core or an E6600 2.4GHzDual Core. So really is it worth the extra $30 for a quad or should I just get the dual?

One last thing. Can I run a 8800GT SC, Audigy sound card, the quad core processor, either 4GB or 2GB of RAM, a320GB SATA HD and 2 DVD drives with a 500W PSU? Or what should I step it up to?

I am not sure if my PSU will run everything I have just ordered so I am making sure. Here will be my updated specs.

-Nvidia 8800 GT 512MB GDDR3OC 650GHz

-500W PSU

-Asus P5B-VM SE Motherboard

-Intel Core2 Duo 2.50Ghz

-2GB DDR2 RAM

-Creative Audigy 7.1 Surround Card

-1 SATA HD 160GB

-Multi Flash card reader

-CD RW 52x drive

-16x DVD RW DL Drive

-16x DVD RW LightScribe Drive

Also will my PC max out Oblivion? I mean full everything with HDR and 8xAA. Thanks.