Problem While Streaming Games Via Xfire

Ok so i play World of Warcraft and I can play it on either low settings or high w/o a problem.

All max settings i sit at 50fps+ constantly. (maybe 30 or so in big towns)

If I play on all low settings. i have 80-120fps constantly.

These are not my issues....

Whenever i start streaming my arena games using xfire my FPS gets massacred down to ~20fps or so. Now i know streaming is strenous on my computer but there is no way its gonna kill my fps by 60-80......

My theory is its my CPU or RAM or something? or that im using a pcie x16 1.0 slot vs. a 2.0 (duno how much of a diff 1.0 vs. 2.0 is)

So my computer specs.

MOBO: Asus P5Rd2-VM (not that great bu meh it works for now) (detailed specs of it below, btw does it support max 2gb total or 2gb per slot?)
http://www.asus.com/products.aspx? [...] 3=179&l4=0
CPU: Intel Pentium D 945 3.4ghz OCd to 3.75ghz
RAM: 2x 1024mb DDR2 533mhz
GPU: EVGA Geforce 9800gtx+ 1gb DDR3ram
PSU: Ultra 750watt LSP (at 12v it runs at 45a its a very good PSU)

My comp stays very cool as well. ~around 40-50C MAX.

So can anyone give me some reasons as to why streaming is soo horibble?

I know people who have worse cards and stream at higher fps then i do, however they have more ram or better cpus (hence those were my theories)

btw a small side fact, i recently upgraded to that GPU/PSU previously i had a stock 450w psu and a geforce 7800gt (overclocked) which ran WoW at about 35-45fps ON LOW settings or so (and when i streamed on it I would drop to 15-20 or so) So I KNOW it cant be my GPU. Cuz my non stream FPS jumped 3fold meanwhile my streamed fps changed almost not at all.

Any help is great or computer upgrade suggestions

should i upgrade my ram to 4gb?
and would overclocking my PSU higher help out my stream issues?

sorry,

just checked the Mobo spec, and relized thathat it does not cater for the Core2 series CPU's, so a new Mobo will definatelybe required if u r gonna upgrade the CPU.

i dont think that overclockin ur CPU any further will benifit u, u definately need a core2 CPU to do the job that u require.

Just to mention it isnt your PCI-e 1.0, you would need something much beefier to be bottlenecked by that.
If its video you are streaming (im assuming so...dont use xfire) then id go with upgrading to a more modern CPU. Dont be fooled into thinking your 3.75Ghz is still fast by todays standards - it handles less instructions per clock than a more modern chip.

AMD provide better value for budget rigs, i would look at a cheapy AM2+ mobo and a 7750 which is great value for money.
If you want to spend more...look towards an Intel E8500.

Aftermarket coolers are Heatsink+Fans that cool your CPU. I imagine you probably know that, but they differ from Retail CPU coolers as they are designed to be more efficient. Some CPU's come with good coolers, some do not. If you overclock then you will most likely need a good aftermarket cooler.
Sometimes, but not often the term is used to describe case fans as well.

If you can sort out a budget and when you would buy (i have 720 in mind as well.....) we can price up the best upgrades for you.