I have an acer desktop (M1100) with Radeon X1200 on board. This system has a 16X PCIe slot, 3 GB DDR2 667 ram (max 4Gb, up to 800Mhz), an Athlon 64 2.7 ghz single processor, Vista Home basic, and a 250 watt stock PSU.
Which graphics card would you recommend to maximize gaming performance, without getting hamstrung by the system's limitations? In short which card do you think hits the sweet spot for a modest computer like this? Some upgades would be OK. Ram, PSU
More aboutupgrade onboard graphics
If your PSU is quality you could go HD4670. Higher rated Cards will need PSU upgrade.
Right now you need to upgrade your powersupply to run your system stable with a graphics card because even a 4670 recommends a 300w psu.