Can i mix DDR RAM Cards of different freqs?
 

I have a P4 machine with 40 GB HD and 256 MB of DDR266 RAM. I got a 512MB DDR333 RAM and when i insert it into a free slot alongside the older DDR266 the computer still detects RAM to be DDR266. Also the performance seems to be more sluggish (both in WinXP and FC4) with 768MB than with the 512 MB alone? Am i wrong in mixing up the frequencies together?

Further I wish to install FC5 from scratch. What is the thumbrule for the amount of swap space i assign for 512 MB ram?

Thanks.

it depends on the mobo as to how it deals with mismatched RAM. I believe most will lower the higher to the lower and go that way, others will silently reject one, others will noisly reject the whole lot.

as for fedora... there is no rule really.. i'd probably give it 512mb, but if space is no issue, then more never hurts. don't pay attention to any hard fast fast rules like it should be double your RAM etc.. this isn't 1987 any more.