Recently I bought an EVGA Geforce 9800 GT and a Corsair 450w PSU. I was wondering if it's safe to dedicate the Corsair to the EVGA via 2 power supplies. *Cross connecting the green and grey cables on the 24pin connector.* But keeping the original PSU in the case and connected to the motherboard, cpu, and fans. So only the corsair would be connected to just the evga. Would there be any shortage problems, or any overloading problems like this? I need to be sure before I go and mess everything up.
I ran two 500 Watt PSU's in one of my systems, but ended up replacing them with a single 1000W after one burned out from overloading (I had screwed up and didn't end up distributing the power like I thought I had and my poor SeaSonic M12 suffered the consequences). The Cooler Master CM Stacker case I used was designed to support twin power supplies and came with the adapter cable you can use rather than following that tutorial you linked, and they're readily available for sale from many places.