Microcenter has a kickass sale, and so I've just upgraded from 512kb to 1024 kb RAM on my Gentoo box, and DAMN IT'S FAST! Apps. load much more quickly. It's true what they say about ne'er having enuf ram.

But now, I have two DIMM channels, and only occupying 2/4 slots-- Channel A[slots 1+2] and Channel B[slots 1+2]...

Two empty slots, (being that there is 512kb of pc3200 DDR ram in Channel A1 and channel B1, respectively).

So, I have that pre-existing 512kb of pc2100 leftover, which doesn't seem to work... when I plug it in BIOS complains about asymmetric rambus configuration (I'm paraphrasing) i.e., you can't have 1.5kb of RAM on my Intel PERL 865 mobo, only whole numbers. ("But if that's the case why, then, will it allow let you have one chip with 512kb, which is not a whole number?" I wonder.)

My Question: I don't want to have a do-nothing 512kb pc2100 chip lying around. So if I wanted to do a further upgrade, say to 2GB of RAM, should I want to buy another 512kb of pc2100 to match the remnant 512kb chip (can you mix and match 3200s with other numbers?), or must I buy more pc3200 (do I need to remain consistent and have all four RAM chips at pc3200?) AND can I possibly get by somehow with putting that third 512kb one of the remaining slots, WITHOUT buying the fourth chip?

Thanks much!

-O

Just like a chain is only as strong as its weakest link, RAM can only work as fast as its slowest module. If you mix and match 2100 and 3200 RAM, your effective speed will be 2100, not 3200 or something in between. To illustrate, suppose that a given task required 2 work units to complete, and magically, half the task was given to the 2100 module and the other half was given to the 3200. Now, even though the 3200 will finish its half before the 2100, the task itself will not be complete until both halves finish - ie, it will be done when the 2100 is finished, and thus your effective speed will never exceed the slowest module.

Anyway, although I understand that you don't want to leave the 2100 module sitting around unused, I would suggest only installing similar sticks of RAM into the box (ideally, I would suggest using identical sticks - same manufacturer, same model). If you plan to double up the RAM again, go with matching 3200. As for the 2100, if you're anything like me over a year or two you will accumulate misc odds and ends, and can pretty much build a "new" PC out of the various spare parts that you've collected, so you might want to just hold onto it. Alternatively, you may be able to trade it to a friend for something else and/or there's always Ebay. Good luck with it either way and congrats on the successful upgrade -- J.W.

Thanks! Now I understand it (a little) better. Seriously, though, that's cool and I'll definitely be sticking with the 3200--which should be getting cheaper sometime in the future. And that old stuff will definitely not go to waste!

Thanks, again.

LLL!