I just swapped out my PSU from an 800w to a 1000w because I am getting a second GPU (GTX470) and 800 watts wouldn't cut it. I swapped it out pretty easily, leaving most of the old cables in place except the PCI-E going into the GPU, I used one of the 3 fixed cords coming out of the PSU. The cords that I unplugged from the 800w fit into a couple of the PCI-E slots in the 1000w PSU, so I went ahead and plugged them in. I have swapped out many PSUs at work on our crappy desktops but they are just 250watts and very straight forward, so I figured this couldnt be much harder - i was wrong.
After all was installed i powered it up and heard a small pop feint smell of burning plastic =( . the fans tried to turn over for a second then nothing but a red flashing light on my motherboard and the GTX470 strip of green lights that usually light up in sequence were all flashing at the same speed. I could even hear a pulsating coming from the speakers.
MOTHERBOARD: Asus P6X58D (3-Way SLI Support)
CPU: Intel® Core™ i7-975 Extreme Edition 3.33 GHz
HDD: * 128 GB Kingston 2.5 inch SATA Gaming MLC Solid State Disk
HDD2: 1TB SATA-II 3.0Gb/s 16MB Cache 7200RPM
MEMORY: 6GB (2GBx3) DDR3/1600MHz
OLD PSU: Xtreme Gear 800w
NEW PSU: Cool Master Silent Pro Gold 1000w
any help / thoughts / suggestions would be greatly appreciated.