to answer the original question as long as you have an alright power supply, then yes, you should have no problems upgrading to the 560ti
afew things to keep in mind, the 560ti is a bit larger than the 8800, so make sure you have enough room within your case to encompass the larger card and keep in mind that the power ports on the 560ti are at the back not the top so that is an additional bit of space that you will need to account for