MSI or Gigabyte 7950?

Apologies in advance this is a noob question I guess lol..

The most expensive 7950 is the Gigabyte.

 http://www.scan.co.uk/products/3gb-gigabyte-radeon-hd-7950-windforce-3x-5000mhz-gddr5-900mhz-1792-cores-dual-link-dvi-i-hdmi-mdp-pl

One of the least expensive is the MSI 

http://www.scan.co.uk/products/3gb-msi-radeon-hd-7950-overclocked-5000mhz-gddr5-830mhz-1792-cores-dldvi-i-hdmi-2x-mini-dp-plusfree-

What exactly is the performance difference between these two cards?  

(another question I had was whether a Nvidea Card works better with Intel CPU's and a AMD Card works better with AMD CPU's? Or does it not matter?) 

Any help clearing this up would be great! Thank you. 

Well the gigabyte one will run quieter, cooler and a little bit faster as it has a slightly higher core clock. The performance difference will be very minimal though. 

No it doesn't make a difference which brand of CPU you have.

What's your budget? I think the 7950 is a great card. The Gigabyte is voltage locked, so its overclocking capability is diminished, but it is cool and quiet. One of the best 7950s is actually an MSI, but not the reference design. Try to get the Twin Frozr. It has the best of everything. Quiet, good cooling, voltage unlocked, appropriately sized, good price.

I'm going to say there's a third way... Can't go wrong with vapour x.

http://www.amazon.co.uk/Sapphire-11196-09-40G-HD7950-Vapox-X-Graphics/dp/B0091MFBZC/ref=sr_1_1?ie=UTF8&qid=1369863296&sr=8-1&keywords=AMD+7950

My budget is £850 and up. If I have to save until I have £1000 so be it lol. 

I do really like the Twin Frozr and its aesthetically really nice too. Just checking how much £50 matters performance wise. 

If the performance is minimal (5-10fps loss) then it does seem maybe better to save £50 to put toward an SSD instead. 

I heard some revisions were voltage locked? But then I also heard that you can get around that by flashing the card. I rate Sapphire, though.

Well, it depends how long before you have enough money. It pays to do it right, but you don't want to be without a system for too long. I think it is acceptable to buy whatever you can. You'll be happy with just about any 7950, if I am honest. Whether it is the "best", or not.

2 weeks max I'd say. Which is why Im thinking of saving for a while longer maybe get an extra £50-100 in the pot lol. 

If they were the same price id say Gigabyte, but the MSI is cheaper and just trails it in cooling & acoustic performance.