I just got a Gigabyte P35-DS3L motherboard with an Intel Core2 Duo E4300 processor from Newegg, but my new DDR2-800 memory won't arrive until Monday. Would it be possible to use my current DDR-400 memory for the weekend, or is it just plain incompatible? I know the performance would be lousy if it is even possible, but it's just so much fun to put a new system together.