I have been having a problem with my Gigabyte P35 being stable with 4 mem slots populated. I am in the process of trying to figure out what to do to get a stable system. I have tried using all settings as Std. No overclocking the CPU or memory. I have tried under-clocking the memory some. I recently upgraded from an Antec 500 PSU to a Corsair TX750 PSU. I have spoke to Gigabyte and they told me that Crucial was not a tested memory with this system. I have spoke with Crucial and they said that using 4 slots w/ Ballistix memory was a problem, but the memory that I am now using does not have a compatibility issue. At some point I am getting the feeling that I can't populate all four slots with this MB. Is there a different MB that anyone can recommend? Just another bit of info, I am running Win 7 Pro x64