I would be going with the UD5P as well, has 2x16bit PCIE slots. I just read a review on the 550 dual core, seems it is a bit of a world beater:D It also is reported that not all 3core and dual core Phenoms are defective, seems that some of them can have the disabled core re-enabled using the BIOS menu of Gigabyte boards and UD5P is one of them.