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Old October 2nd 07, 10:50 PM posted to alt.comp.hardware.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt
Paul
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Posts: 13,364
Default Questions about DDR RAM

Igor wrote:
I'm planning to add some memory to a PC. The motherboard supports "DDR
up to 333 MHz (enhanced) memory bus."

333 MHz (PC2700) or slower DDR SDRAM isn't easy to find on today's
market, and when you do find it, it's considerably more expensive than
the DDR which runs at 400 MHz (PC3200). What would happen if I bought
400 MHz DDR RAM and installed it in a motherboard which only supports
speeds up to 333 MHz (PC2700)? Would it work? If it did work, would it
work as well as the slower PC2700 RAM?

I've gotten conflicting answers to this question. Two computer stores
told me that it wouldn't work. Another store and a book I consulted said
it would.

I'd also like some opinions on which brand of RAM I should get. Kingston
and Samsung are ubiquitous where I live, so the choice comes down to one
of those. Both brands are about the same price, with the Samsung being
marginally cheaper.

Finally, would a 128 MB stick of 266 MHz DDR RAM be able to run in the
same computer as, say, a 512 MB stick of 400 MHz DDR RAM? If so, would
using both at the same time degrade the performance of the faster RAM?


If you tell us the motherboard make and model, we give better advice.
If the machine is Dell or HP, tell us the model number etc.

Faster DDR is compatible with slower speed applications.

Whether mixing RAM makes sense, really depends on what speed the motherboard
and its current configuration, would support. If your processor is limiting
the speeds that the Northbridge can run the memory, then maybe removing the
128MB stick would make no difference.

Details count. Motherboard and processor information would help. You can
also get some hints from looking at both:

http://www.crucial.com ("Crucial memory advisor")
http://www.kingston.com ("Memory search")

HTH,
Paul