I need to upgrade a Dell Optiplex small mini-tower computer to run Second Life decently (don't ask me why). The machine has a 4X AGP slot and PCI but no PCI-E. I'll obviously be upgrading to 1 GB of memory (the maximum it supports) but I'm concerned that the power supply may not be good enough to support a powerful enough video card. I'm not positive, but I think the power supply it came with is 250W max output. Anyone have any suggestions for a a video card that this system will support and be able to run Second Life?