Are DDR 2100 ram modules (266mhz) backwards compatible with 200mhz bus CPU's?

[mr_mf_wizard]

I recently purchased a Socket A mobo which will only accept DDR ram. I have a Duron 900 mhz processor that runs on the 200mhz front side bus (or whatever). Do I have to buy DDR 1600 ram, or can I buy DDR 2100 ram and use it with the Duron? I know that you cant use DDR 1600 ram with a 266mhz bus processor, but what about DDR 2100 ram with a 200mhz bus processor (backwards compatibility). Is this possible? I will be upgrading my chip eventually, and I dont want to have to buy new DDR 2100 ram later on and let the 1600 modules go to waste.

[r0l0e]

interesting question. i've never really tryed it on my board and unless someone here have already tryed it.
let me know how it goes.

i'm interested on the outcome also.

side note: you may be able to run that Duron at 133fsb or 266ddr if you knew what you were doing.

[Wizzard~Of~Ozz]

Since this seems very similar, I would think

PC2100 is equiv to PC133
PC1600 is Equiv to PC100

looking at it that way, PC133 operates just fine at PC100 speeds, so PC2100 will run just fine at PC1600 speeds, some PC1600 DDR might actually run at 266FSB, but it's not certified for 2100 speeds, there is no physical difference that I know of, the chips bin speed determins the speed rating, if it fails 2100 but passes 1600 then it get's thrown into the 1600 bin, I would hope that most manufacturers test the speeds for 1600 at 105Mhz, 2100 at 138Mhz, to ensure that it's not marginal working.

Doh, after reading the question, I was running an Epox 8KHA+ with a duron 750Mhz with the FSB at 100, Mem at 133, if your board supports this, but I have booted with 100/100 and it works just fine.

[newbie~wan]

I am 99% sure it will work. Hopfully we can get a few more members in here to solidify that vote.

[iosubsys]

it should work fine

[FreakyOCR]

It's exactly like PC100/PC133

PC133 is backwards compatible....

Using PC133 with a 100fsb processor will give you more overclocking room....

Same with DDR. Having PC 2100 (266) will give you more overclocking room on a PC1600 (200) setup.