Differences between GPUs?

eh they are both kinda same.. choose the one you like the most, again they have same performances : stream processors 1280, 256 Bit, Core Clock 1050 MHz, etc

Yeah they both also have dual fans, I guess get it from the store you like most since they are the same price as well.

Actually Scan doesn't have that card in currently "Item currently awaiting an ETA. ", So the one from Novatech is likely the best choice.

http://www.novatech.co.uk/products/components/amdradeon...

This one is a bit more(£10 more) and comes with Far Cry 3 a fun game if you don't already have it. And has 3 fans, I'll admit I'm a bit of a Gigabyte fanboy when it comes to their video cards.

Would it work with my build?

For sure

Yes, so long as your hard drive isn't directly behind or rather in front of it.

Your case has 230mm of space with a hard drive in front of the video card and 330 without one. The Gigabyte is 280 mm in length.

Twin Frozr is the better of the two. It has superior cooling.  

http://dk.msi.com/product/vga/R7870-2GD5T-OC.html

http://dk.msi.com/product/vga/R7870-Twin-Frozr-2GD5-OC....

Here you can compare the words of MSI themselfes.

True the Twin Frozr has 5 heat pipes versus 3 on the other MSI. So the cooler is superior to it's non TF brother.

But the Gigabyte has superior performance in games thanks to it's higher OC and is quieter and cooler than the Twin Frozr as seen below

Temps Gigabyte


Temps MSI Twin Frozr


Edit: Actually the Twin Frozr is pretty darn hot in comparison and louder to boot.

Noise
Gigaybyte


MSI Twin Frozr