as always i turn to you good people for help.
i bought 2 sticks of pc2700 ddr ram (512) today to replace my old pc2100 ram.
i installed them and the computer just rebooting. it runs fine with one, it runs fine with 1 pc2700 and 1 pc2100, but i cannot get the two of them to work together.
the m/b is a biostar m7ncd pro.
i am running an athlon 2800+
i also have the latest bios on the m/b.
any help is appreciated
thanks

Dude, Throw away the 2100 stick,
Your 2800+ should have a 333FSB,
which is 2700.
The memory probably run at different timings,
Which also would cause you problems

so how do i fix it?
ram is the same brand etc.

I think .... he runs @ 333 MHz right ???
but ur 2100 is only capable of 266MHz so the only chance to get them work is to UNderclock the 2700 modules .... AND watch out for RAM timings maybe the 2700 got better ones which were set by SPD and the 2100 cannont handle them ....

1. insert ONLY the 2700 modules
2. define 266MHz for RAM or if asynchronous does not work get 266MhZ FSB
4. set RAM timings to 4-4-4-7-2

if it works then .... raise timings to get best performance out of this really slow combination ....

so am i making these changes in the bios or on the board itself?
i find the whole thing kind of odd, the board should run up to 3200 ram safely, and i am using the ram the m/b maker told me to use. (i wanted to get giel, but i dont overclock and it wasnt recommended)
thanks again as always

... if you have jumperfree mode enabled (default) you have to set up these settings in BIOS .... from your speakings I get ... you have done nothing .... the 2100 was forced to run @ 2700 speed an errrrrrrrrrrrrrrrr not possible due "OC"

im not sure what the 2100 was running at. i never messed with the clock or volt settings.
all i noticed was i put a new processor in 2 weeks ago and the fsb went from 133 to 166. does that mean the 2100 was being forced to run @2700 settings?

133 - 166 - 200 are the "ground" frequency ...
means in DDR
266 - 333 - 400 nothing new ....
RAM rating ( 2100 2700 3200 4000) is calculated by DDR FSB*8
means 200 MHz FSB = 400 DDR * 8 = PC3200
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u know ... so set it to 266 to get all modules running at one BUT this is really BS take the 512 @ 2700 thats much more worth then the setup you want ...

May be try to set the ram speed at mobo bios to auto if it doesn't helps try to set it to 266 which force the 333 to run at 266.