I recently purchased one of these for my Dell Inspiron 530s (having also bought a slim-tower without realising its limitations). Its a fantastic little card and runs COD4 with ease. I was a little concerned about the rather puny 250W power supply in my case handling the card, so I also bought a 450W Thermaltake VGA power supply. This has to sit outside the case (with the cables running out through a spare PCI slot) as I don't have a free 5.25in bay to house it, but this set up seems to work fine.

The card is pretty noisy under load, presumably because it has a smaller than average fan to keep it low-profile, but its not too intrusive.