How complex is it to tell straight up, that it's 50-50 if new sticks will even play with old? Ypu also say unless it is 'matching' that OP gives up dual channel (can take any 4 1GB sticks and if they play it's still in dual), with mixed sticks it doesn't always go to the lowest data rate/timings of the sticks of the sticks, and actually unless you have an older mobo, if Intel and you have the sticks in the proper slots you should be in flex mode and have 4GB in dual and the odd 2 off the 4GB stick in single channel mode, again nothing complex, just presenting facts