I wanted to buy a Pavilion 550z and upgrade the PSU and GPU. The Pavilion 550z is a customizable PC on HP , and I kept everything at the default except the CPU , which I put to a A10-7800 (Would It be a better idea to get a 7700K?). So , someone earlier on a different forum told me I should buy a Corsair PSU (Some one said that on here too. But the other guy suggested a CX 600M) I also plan on buying a EVGA GTX 960 SSC 2GB GPU. I already know the GTX 960 is okay with the motherboard the Pavilion uses (MSI Orchid2-S which has PCI(e)). Now , I don't know the dimensions of the Pavilion 550 , so I would like to know if the GTX 960 can fit in that PC , and I already know the PSU can fit (Or at least that's what's someone else said). But , is this entire PC a safe thing to do?