I have this HP Pavilion Desktop. As you can see, that page says the memory speed supported is PC2-4200. It currently has a 512 MB stick - CPU-Z Screenshots: hxxp://i41.tinypic.com/j5clj6.jpg and hxxp://i39.tinypic.com/20tldlc.jpg

However, a crucial.com scan gives a slightly different report - hxxp://crucial.com/systemscanner/viewscanbyid.aspx?id=5718CFE831D926C3 It says the system can support PC2-5300 memory.

So my question is which one should I trust? I want to upgrade the computer's ram to 2 GB (the maximum supported), because XP Media Center is giving me problems and I will install Windows 7 on this. PC2-6400 is the most common DDR2 memory I have been able to find here in the market. Will it cause any problems if I install 2 × 1 GB PC2-6400 DDR2 memory sticks (in dual channel) in this computer, (afaik, it will just run at the lower speed of 533 MHz, or whatever the motherboard supports), or do I absolutely need to get PC2-4200 sticks?