I purchased an HP 7757, fully intending to upgrade the 7500 LE to either a 7600 or 7900. In researching the requirements, I learned that my PS is only 300W and both the 7600/7900 require larger PS units. I also learned that the PS in the HP is proprietary and cannot be upgraded with a third party PS. In poking around this issue, I've come across many posts suggesting that all one need do when upgrading a VC is to simply 'pop a better card in'. As it turns out, it's not always that simple. Be forewarned!