Several months ago I purchased an 'off-the-shelf' PC from HP (model number 500-141ea). I was primarily using it for home purposes and more recently some casual gaming. The performance however is not really that great. I researched it, and found that I could crossfire or have a 'dual-graphics setup' with the A8-6500 in my PC and an AMD HD 6570 or HD 6670. My peferance is the HD 6670 1GB because of its superior performance for not a big price increase, and also (I believe), it doesn't need PCI-e power connectors which may be an issue because my PC probably has a low wattage PSU and no PCI-e cables. Before purchasing I have looked inside my PC to make sure my motherboard had correct PCI-e x16 slot (better safe than sorry) and I found that there is alreday a discrete graphics card installed, which I am assuming is not the GPU side of the A8-6500 because it is supposed to be integrated. I believe it to be an HD 8470 from looking at the HP website, but I am confused because I cant't find it as a discrete card on Amazon or similar. Also when I go into AMD Catalyst Control Center, and go into Dual-Graphics, it shows that both an APU and GPU are active, and it wouldn't show that with A8-6500 integrated grapichs, would it? My main question (sorry), is would the HD 6670 improve FPS on games, compared to HD 8470. Another thought I had was to buy a new motherboard with two PCI-e x16 slots, and use APU, HD 8470 and HD 6670 as crossfire, but I don't know if this will work or not.
The 8470 is a discrete card, but only available OEM for system builders like HP, not available separately for consumers: http://en.wikipedia.org/wiki/Radeon_HD_8000_Series
I haven't found a compatibility chart that covers hybrid crossfire, but I think to include an 8470 and a 6670 in the same crossfire setup (assuming the chipsets are compatible, which they might not be for all I know), you'd at least need a crossfire bridge, and it doesn't look like the 8470 has a connector for that. Also, the 6670 has a higher TDP than the 8470, so even running it in place of the 8470 would be pushing the limits of that 300W psu, and you'd definitely want a stronger psu to run both cards.