Hello.
I have upgraded the 7570 to Sapphire Ghz Edition HD 7870 OC video card with no problems. Installation was extremely easy!!!!
Currently I have it overclocked to 1100Mhz and Memory Clock at 1350 Mhz I can run Battlefield 3 at Ultra with no problem just had to step down the anti aliasing due to the fact it is only a 2gb gddr5 card. I also have the stock PSU installed as well. I would not overclock past that point due to the PSU your system will crash.
System Specs:
OS - Windows 8 - 63 bit
Graphics Card - Sapphire Ghz Edition HD 7870 OC (GPU Clock(1100Mhz), Memory Clock(1350), VDDC(1250)) Overclocked with Sapphire TRIXX. Temperature under full load does not exceed 58 degrees Celsius running Battlefield 3 on Ultra.
Processor - Intel Core i7-3770 @ 3.4Ghz
Ram - 8GB
HD - 1 TB Western Digital
PSU - Stock Dell 460 watt. If you want to push the card further get a larger PSU (600 + wattage) and a few more fans installed in the case.
I will be posting more scores from the card and the XPS 8500 after I receive Crysis 3, Bioshock Infinite, Tomb Raider, and Far Cry Blood Dragon. BTW its a perfect time to buy the card only about 200-240 and comes with 160 dollars worth of games.
Enjoy the hunt for the best solution!!!!