I payed 40 dollars each today for 2 Axel3d nVidia GTX 550 3gb ddr3 cards both unopened. I will have my brother install these tomorrow. Will this be much better than my crossfired ATI Radeon HD 4800s?

What resolution do you game at?
DDR3 video cards take a fairly beefy hit at 1080P and higher, not so bad at 720P.

I would probably think it's a wash performance wise.

Personally, I would sell the GTX 550's and the 4800 cards and pick up a single GPU that would wipe the floor with them all.

Here is how the GTX 550's (GDDR5) stack up to Radeon 4870's.
http://www.anandtech.com/bench/Product/513?vs=541

The DDR3 version would be slower.

What card do you recommend?

Also I game at whatever resolution the game allows without it running like a slide show, usually at 720p.

no. just no. lol. a single card that would beat 2 cards would cost way more than $40. Also DDR5 is not Gods gift to gaming even if Sony is using it in ps4. 6gigs of ddr3 is more then enough for any game out.

asking a console gamer about pc parts is like asking a kart driver to give you his opinion on the best f1 race car out there.

So I should just install these cards?

What card would I recommend? At-least a couple of Titans. :P
But, people have budgets usually.

Haha, you just made my day!

No really, if you think a DDR3 video card is even in the same league as a GDDR5 one, then you're dreaming, it's a night and day difference.
I'm also not a console gamer either. (Look in my sig.)

I just saw the specs of your PC how the fuck do you cool your system? lol

It's custom water. :)
And Winter! WOO!

LOL wow your rig is godlike!