Minimum System Requirements
OS: Windows Vista (Service Pack 2) 32-Bit
Processor: 2 GHz Dual Core (Core 2 Duo 2.4 GHZ or Althon X2 2.7 GHz)
Memory: 2 GB
Hard Drive: 20 GB
Graphics Card (AMD): DirectX 10.1 compatible with 512 MB RAM (ATI RADEON 3000, 4000, 5000 OR 6000 series, with ATI RADEON 3870 or higher performance)
Graphics Card (NVIDIA): DirectX 10.0 compatible with 512 MB RAM (NVIDIA GEFORCE 8, 9, 200, 300, 400 OR 500 series with NVIDIA GEFORCE 8800 GT or higher performance)
Sound card : DirectX compatible
Keyboard and Mouse
DVD ROM Drive
You are below minimum spec for processor speed, That graphics card is ok, but yoyr cpu cant provide it with enough data..thats why it plays poorly
Something else I didnt catch..the 6870 requires about a 500watt power supply. As for the cpu, what model is your HP system, then we can see what cpu's are compatable. OEM's are notorius for not supporting a variety of processors, but maybe there will be something better
I upgraded the psu to 600w shortly after realizing I couldn't power the 6870. After a bunch of research and digging around I was able to determine the motherboard is a MCP61PM-HM (Nettle3)
It'd be nice if I didn't have to replace that too, but I'm willing to if it means making everything finally work.
Your motherboard is socket AM2+, and according to info here: http://bizsupport1.austin.hp.com/bizsupport/TechSupport...
This board only supports Phenom processors up to 89 watts. I dont even know where you would buy a Phenom..maybe used on Ebay, but you would end up with something only slightly better than you have now.
It looks like it's time to build a new pc. You have a head start though. You can reuse your current powersupply, video card, hard drive, and optical drive.. possibly the case. Looks like a pretty standard Matx board, so you will need a motherboard, cpu, and ram. There are a lot of options, but all is determined by your budget.