Graphics card able to burn out a PSU ?

I purchased a new rig roughly 1 year ago which i then shortly after upgraded:

Starting rig:
Asus P5n-e SLi
Intel Q6600 Quad-Core
4x A-Data 2gb ram
Nvidia 9500gt 1gb
450W Winpower PSU

A standard computer you may say for a year old....
I then replaced the Graphics card with a Sapphire HD4870 1gb and the PSU from 450W to a 750W, since this upgrade i have had 4 PSU's "burn out" after trying to turn the computer on in the morning. Is it possible that the graphics card is the problem or a combination of certain components?
If any other details are required please tell me and ill be happy to provide

Any help is much appreciated

Nathan Ledgerton

What kind of PSU's are you upgrading to? Brand/model?

SO when you replace the PSu everything works fine again until it burns out? What are you plugging it into? the wall? or a surge suppressor?

Is it a bad surge strip? do you get alot of storms? Oddly enough I knew someone that blew out a few because they were on an old surge strip and lived on a farm near alot of trees. They had alot of lightening and also had alot of fluctuating power.

What is your brand of PSU's that you have used in the past?

Power strip protectors too close to electronics and too far from earth ground simply give surge even more destructive paths through the computer. Retail salesmen do not mention this. Therefore it is not well known.

If you had a surge, then how many other appliances are also damaged. Computers are required to be some of the most robust devices in a building. If damaged by a surge, then you have failed dimmer switches, bathroom GFCIs, dishwasher, clock radio, smoke detectors. What else was damaged? Nothing.

Surges occur typically once every seven years. Another fact obviously not known to so many who recommend only what salesman promote.

Protectors too close to electronics can contribute to electronics damage. A properly purchased protector earths direct lightning strikes – and remains functions. So was it so ineffective as to fail? Or so ineffective as to divert that surge energy harmfully inside the computer? Either way, it provided the protection that the manufacturer specs sheets defined. View those specs sheets. Where does it claim to protect from each type of surge? It does not. Ignore that silliness about the protector – promoted mostly by those without sufficient electrical knowledge – who are grasping at myths due to insufficient power supply knowledge.

Your power supply failed one of two ways. Either it suffered a manufacturing defect - the most common reason for failure. Or the load was always so excessive that the supply finally went into foldback current limiting. A safety feature because all power supplies must even have all outputs shorted together - and nothing is damaged. Many do not even know of this 50 year old safety function. Therefore assume the supply has failed.

Reduce the load. For example, remove the video controller, keyboard, mouse, and a few more items. Then try to start the computer. Does the supply work?

If yes, well you probably always had a defective supply. A defect you could have seen with a multimeter maybe a year ago. A defect that finally caused a failure.

Stop wasting times with surge protector myths. Connect that supply directly to the same AC power that is not destroying dimmer switches, TVs, the furnace, and light bulbs. Deal with the problem. If using a multimeter, the many 'it might be this or might be that' answers would be replaced by 'it is this and you need to do that'.

So, is the supply good but undersized? Or has a manufacturing defect finally caused failure? Proper experiments answer those questions – without doubt or speculation.