How much is this CPU/Ram bottlenecking my graphics/games?

Hi everyone. This is my first post on the forums, and I'm not quite sure that this is the right section,but my question is indeed CPU related, so here goes...

I recently purchased a Radeon HD 2600 Pro AGP with 512 mb to go into my current system, which is a Intel D865Perl with a 478 2.8 ghz Pentium 4 HT (512/800) with 1 gig of DDR 400 running in single channel and a 550 watt PSU.

Anyway...

I'm wondering how much this CPU and Ram is bottlenecking my game performance. I'm considering upgraging to a 3.2 Pentium 4 since they're pretty cheap on ebay right now and upgrading to 2 gigs of dual channel since my friend's giving me a good deal. I'm almost satisfied with my rig's performance right now, but I just wanted to know how dramatic those 2 upgrades would be for my frame rates in games.

I mainly play the Orange Box and Doom 3, but want to get my frame rates in Bioshock and UT3 closer to a constant 30fps (which I'm very close to) without turning settings down. Something like buying a better board isn't much of an option, but I'm mainly interested in maxing out the potential of my current system anyway.

What's your take, guys? Would dual channel ram and a 400 mhz faster processor make much of a difference? I'm not expecting a miracle, but I just wanna see my motherboard's full potential. Thanks a bunch!

You aren't going to be getting a whole lot more...probably more with extra RAM than a different processor in that system. Also, your graphics card is probably holding you back as well, but with an AGP system, its really hard to recommend a card since they are hard to find and/or very overpriced anymore.

I would say 2 gig RAM would be your best bet first. I would say different GPU, but you a) just bought that one and b) its AGP.

A friend of mine's selling me two 1 gig sticks for 50, so I think that's my best bet for now. Also, will upgrading to dual channel make a noticeable difference? I hear that Pentium 4's run much better with dual channel.

The dual channel probably won't make a difference, but the greater quantity of RAM probably will.

People often underestimate the difference a new cpu can make.

I had a Pentium D 3GHz paired with a Radeon 2600XT and in guildwars when I would stand in the middle of a huge crowd in town my FPS would be about 30.

With my new E2220 when I stand in a huge crowd my FPS is 58 (keep in mind I have vsync enabled so my max is 60)

So yea it helped some in that game.