Its 256g mb... agp 4x/8x and ddr3 memory. However I installed it and when i turn my computer on the montior idles... IT IS GIVING ME NO SIGNAL AT ALL.(meaning the light goes from green to orange) I have the slot for the card, an ultra- 500 watt power supply with 12v/26A my latest bios updates installed... Used a driver cleaner cleaned all my drivers.. and still its not working.. thought it was a defective card but got a new one and its doing the same thing. I have a dell dimension 8200 (which i recently upgraded the power supply...) any ideas on whats causing this issue? my previous card was an ati radeon 9800pro 128mb which whats in now cuz its the only card that works at the moment... please help

what is the brand, model, and amperage ratings on that power supply. you'll need a name-brand high quality supply of at least 500w to run a 7800 gpu.

what usually happens in this case is that the power supply, although rated to handle the card, will not because it was built using lower quality parts of less efficiency.

its an ultra-v 500 watt power supply with a 12v/28a rating

Most people on this forum will trash the Ultra brand PSU's. This is with some good reason, in some cases. I currently have an Ultra X-Connect 500W, and an Ultra X-Finity 500W. The first X Connect had to be RMA'd because the 5V kept jumping around, but was replaced with no hassle. The new X model, and the X-Finity model have been rock-steady.

That said, I have heard of many, many, problems with the V series. In fact, Ultra is unloading them at dirt-cheap prices, so yours might be suspect.

In closing, I do not really recommend Ultra, because there are many other reliable brands, for around the same money (or even less) than Ultra's top-of-the-line versions. Antec, Fortron, Sparkle, and others come to mind. I use Ultra sometimes- because I get good deals, and if they are registered online, they have a lifetime guarantee. Plus- none of 'em have fried my systems yet!