Power supplies are rated on output power. There is ALWAYS loss in the process converting from 110 (or 220) to 12V. As such, the INPUT stages are over-engineered to make up for this loss. For example, MY 750 watt PC Power and Cooling has input stages designed for up to 1100 watts to be pulled from the wall. When fully loaded, that PC Power and Cooling is actually KNOWN to pull up to 950 watts from the wall.
I work in IT and have taken advance courses in electronics course. Your taking about AC coming into the PSU and DC coming out from the PSU. In all my IT and electronics courses, it mentioned that AC wattsis pulled from the wall and converted to DC watts in the PC. During the transformation form AC to DC there is lost of watts in heat since current and resistance at the PSU (ie I(current)*R (Resistance)). This is why it can not be 375 watts like you said or the PSU would get destoryed. It is not rated for 375 watts AC. It is rated for 300 Watts AC. Plus you are confusing the poster since the poster now thinks that it is a 375W PSU.
- Card works without any problems
- Card does not work and no harm to componets
- Card works but your componets get damage
Most power supplies do not give full 300 watts so like waldojim said. If you get 200 watts it might work, but 300 let say is running at 80%. 300 *80% is 240 watts. Since the computer is a few years old, than take off another 20%. 240 * 20% is 192 watts.
If you use the 5670 card and it works, do not run any major stress test on the computer.
I would go with Gefore 9500 or 9800 card. Those should work with your PSU without problems.
The power supply is rated based on what it can deliver, not what it draws from the wall. a 300 watt PSU @ 80% efficient draws about 375W from the wall. The 9800GT will draw considerably more power than the 5670, both at idle, and at load.
My PSU is 375W. Did the label it wrong with 300W?
No, the PSU is rate at 300W AC.
waldojim is confusing AC and DC power and got 375W of AC. All oneline source that I check say that the PSU in this model is 300W rating.