Advice on Graphics Cards

[Coris]

Hello there!
May I sneak in and ask for your opinions too?
I am running a PC with the following specs:
Win 7 Professional
Asus M4A77T
AMD Phenom II X4 955
PowerColor Radeon HD 6850
630W PSU
8GB RAM
(Nothing overclocked if this might be important.)
(Always had AMD/ATI Cards!)

Well, since a while my Graphics card sometimes is showing issues right after boot when my PC was off over night. Usually in my browser some nice checkboard patterns show up. They disappear after a while and when I hover with my mouse over them. My colleague at work said it might be a heating problem.

Long story short...
I want to get a new card but can't decide. Around 200€ is what I want to spent and the cards I checked out at that german Online Store I use to order at, offer them around that price.
Checked them both out on Newegg too if this helps xD


ASUS GTX660
http://www.mindfactory.de/product_in...--Retail-.html

http://newegg.com/Product/index?item...82E16814121660

(Hopefully I found the right models. Not sure which of them at Newegg is the OC version and also not sure if I need an OC card.)


ASUS HD 7870
http://www.mindfactory.de/product_in...--Retail-.html

http://newegg.com/Product/index?item...82E16814121649


Newegg links used to be mobile links. Just removed the m. I hope they still work.
Thanks in advance!

[Alegis]

If youre interested in free download codes for Bioshock Infinite and Tomb Raider (never settle reloaded program from AMD available at mindfactory, caseking.de and alternate.de), get the 7870.

http://forum.chip.de/grafikkarten-so...a-1696517.html