Beating face against wall

I finally got around to building my first PC, and of course I impulsed bought a whole computer without diving deeper into research on all my components. Since ordering I have sent back quite a few parts (all ordered through newegg, because they offer the no interest/no payments). 

Mobo: ASUS M5A99FX PRO R2.0 AM3+ AMD 990FX

CPU:  AMD FX-6300 Vishera 3.5GHz (4.1GHz Turbo) Socket AM3+ 95W

GPU:  MSI GeForce GTX 650 Ti BOOST 1GB 192-bit

Now those are/were the specs I have since sent back the two GPU's, and the PSU. The part that I am beating my head against the wall on is which GPU to go with now?

Nvidia 780 acx cooler

http://www.newegg.com/Product/Product.aspx?Item=N82E16814130918

or

HD Radeon 7990

http://www.newegg.com/Product/Product.aspx?Item=N82E16814129277

I know my CPU is going to bottleneck my GPU. I'm already planning on upgrading that too. For now I just want to be able to play some damn games cause this dell with integrated graphics blows...but from what I've watched/read about the AMD is they all seem to have driver issues...

Here's what I need answered

1.) From what I know my mobo should be able to handle either of these, or am I wrong on that?

2.) What I've heard on some videos about which brand to go with AMD, or nVidia is AMD is for gaming, and productivity, while nVidia is strictly gaming (or better for gaming). Is that right, or wrong?

3.) I'm planing on going with this PSU, will it suffice?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817182238

4.) Since I already have nVidia drivers installed on it will I run into any problems? (ex. Will windows have to be reinstalled if I go with AMD...)

If anymore specs are needed just check my profile on here.

Any advice is greatly appreciated, and it is almost 3:30am where I'm at so I won't be checking on this for another 6-7hours. Thank you in advance.

-2Stoned

1) All modern MoBos support all modern GPUs

2) AMD is better at OpenCL while Nvidia has exclusive features like CUDA and Physx (which I consider gimmicks). I usually go with the one that runs game better for the price. Although I would never buy a dual chip GPU. 

3) Huge overkill. You don't need 800W (for GTX 780) and you don't need 80+ gold. 

4) Just uninstall drivers before swapping GPUs. 

Cuda is not a gimmick, its just sodding proprietary.

Price aside which would you choose if you enjoy eye candy, and your going back to college to continue your computer science degree?

As for the 80+ gold I thought that stamp was a reference to it's energy efficiency?

Already sent back the MSI's, so will I have to reinstall everything? -_- (I have no other removable graphics card laying around)

Thanks again.

Price aside which would you choose if you enjoy eye candy, and your going back to college to continue your computer science degree?

"eye candy" is a subjective term. I consider all unnecessary lights such as keyboard backlight and fans with LEDs ugly. 

As for the 80+ gold I thought that stamp was a reference to it's energy efficiency?

 Yes. But there's no point in spending so much money on PSU. A 600W bronze or silver rated PSU would be completely fine. 
 
Already sent back the MSI's, so will I have to reinstall everything? -_- (I have no other removable graphics card laying around)
Just uninstall old drivers first thing after you power it on. 

Cuda is not a gimmick, its just sodding proprietary.

That's what makes it is a gimmick when there's OpenCL. 

a good 750w should be fine if you go 7990, a good 550+w with 42+amps should be fine for a 780. if you eventually want 2 780s 800w- 850w is a good amount.

Thanks again guys. Oh when I said eye candy I was just referring to maxed out graphic setting. Sorry, I should have been more specific.

I can't think of a game what wouldn't look good on GTX 780.