Based on Jeff Block's article on "Beginners Guide to Buying a New Computer" and the compatibility table in it of memory to processor FSB, I'm trying to upgrade the RAM in my eMachines desktop PC, model T3828.  eMachine's techs are telling me that I have two module slots which will hold a maximum module of 1024MB each.  I think I currently have one 256MB module installed since I purchased it.

One question I have is would it be worth the money to buy both 1GB modules to fill both slots now, or would it be better to only fill one slot?  What TigerDirect.com (eMachines referral) offers through it's Memory Configuration website program is a 1GB module (Ultra 1024MB PC2700 DDR 333MHz) for $49.99 per module.  eMachine's techs advise me that any PC2700 memory will work on my system.

However, in Jeff's memory to processor table the DDR 333 memory does match the PC2700, but my PCs specs say that my CPUs FSB is 533 MHz.  In the article I think he said that the FSB should match the memory, so, based on the table, I was wondering if a memory module with a DDR2 533 designation, which is called PC2 4200/4300 would work?  Or would it be incompatible?