I just upgraded to 10.3.5 in my old Mystic machine and I have 4 sticks of 512mb of RAM. Three are PC100 and one is PC133 (threw it in there a month ago and no issues). Before my OS upgrade, System profiler reported the RAM as 3 PC100 222 sticks and one PC133 333 sticks. Now it reports that there are 2 PC100 222 sticks and two PC133 333 sticks. Any idea as to what this could be? XLR8yourmac had some reader postings about it but no word about why or potential problems this could cause.