yeah it will, what you mean by slower? you cant mix pc2700 and pc2100 and get them both to run at 2700, infact that setup prolly wont be very stable at all. its not like 133 and 100 ram, much more picky is ddr. if you mean cheap pc2700 and corsair 2700 then it will run fine sure. just dont expect the cheap ram to be same specs as the corsair. your system will run fine tho, but TWO sticks of corsair ram in one day will give beter performance than one cheap and one branded stick yeah. the fact your card has 64mb ram might also be a factor in the pacific maps, i have heard other ti420 owners complaining about it and on large desert maps too they get lower frames, but still playable on the desert ones. its not a bad card, but not amazing either. damned graphix cards cost too much, i have a raddy 8500 64mb and a ti440. the raddy ive lent a friend indefinatley, hes having to upgrade his PSU just to borrow it tho lol