Which memory should I buy?

[3in4]

I have a P4 1.8A (512 L2) CPU which runs at 400mhz FSB.
My motherboard can run 400/533/800 and supports Dual Channel.
I won't be overclocking at all.

I want to get 2 sticks of 256mb so I can run in Dual Channel mode, but my question is
should I buy PC 2100, PC 2700 or PC 3200? They are all about the same price, maybe 2 or 3 dollars separating the PC2100 from
the PC 3200. I want to buy what will work best, fastest, most stable. Which speed?

Thanks!

 

[Homer J. Simpson]

PC3200 is for 400MHz FSB <=== You need this one.

PC2700 is for 333MHz FSB

PC2100 is for 266MHz FSB

I have a P4 1.8A (512 L2) CPU which runs at 400mhz FSB.
My motherboard can run 400/533/800 and supports Dual Channel.
I won't be overclocking at all.

I want to get 2 sticks of 256mb so I can run in Dual Channel mode, but my question is
should I buy PC 2100, PC 2700 or PC 3200? They are all about the same

price, maybe 2 or 3 dollars separating the PC2100 from

 

[3in4]

Thats what I was thinking. But, my main machine is a p4 2.8ghz running at 800mhz. I have PC3200 in there too, does that mean
its too slow for it?

 

[stanmc]

Thats what I was thinking. But, my main machine is a p4 2.8ghz running at 800mhz. I have PC3200 in there too, does that mean
its too slow for it?

Isn't the FSB:

200 which equals 400 at Double Data Rate

166 which equals 333 at Double Data Rate

133 which equals 266 at Double Data Rate

The 800MHz is 200 Quad-Pumped to equal 800??

 

[Paul]

Thats what I was thinking. But, my main machine is a p4 2.8ghz
running at 800mhz. I have PC3200 in there too, does that mean
its too slow for it?



Think first about memory bandwidth balance. Your FSB800 processor
is 64 bits wide. It transfers data at a max burst rate of 6400MB/sec.
The memory are 64 bits wide and run at DDR400. They have a max
transfer rate of 3200MB/sec and you have two of them. A perfect match.

For the FSB400 machine, processor transfer rate is 3200MB/sec.
A stick of DDR266 is 2128MB/sec. With two sticks, there is more
than enough transfer rate to meet the burst limit of the processor.
In fact, if you look at the table in the manual, the FSB400
processor is limited to running the memory at DDR266.

Homer's advice is good in terms of "future-proofing" your purchase.
If you ever upgrade the processor, then having some PC3200 memory
in the FSB400 machine will prepare you for the upgrade. PC3200
memory should be compatible with transferring at the limited
rate of DDR266 today, and be ready to run at DDR400 tomorrow.

Also, if you want to try overclocking your 1.8A to a slightly
higher rate, then a more capable memory won't hurt.

Finally, think of resale (Ebay) value. Selling PC3200 memory is
going to be a lot easier than selling PC2100 memory. While the
purchase price difference may be small, the resale could be
a lot different.

HTH,
Paul

 

[3in4]

Thanks alot paul. thats the info I was wanting to know. It just didnt make sense when ppl were telling me that 400mhz ddr was
right for my 800mhz fsb machine, but also the right one for my 400mhz machine. Now I see that 266mhz ddr is actually the
right fit for my 266mhz machine, but by buying faster I give myself more leeway.