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Latency vs Bandwidth

Last response: in CPUs
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May 6, 2002 10:55:54 PM

I know that memory latency is being reduced as memory runs on a faster FSB. So... I am curious. Is the speed increase on the P4 533 with PC1066 mostly due to the increased bandwidth or is it mostly due to the lower latency, or is it a pretty even combination?

Idealy, someone could test it by running 4 sets of benchmarks. P4 400FSB with PC800, P4 533 FSB with PC1066 only 3x clocked (IE, at 800 (2 x 133 x 3)), P4 533 fsb with PC1066 clocked normaly, and (not sure if you can do this one) P4 400 FSB with PC1066 clocked at 5xFSB (2 x 100 x 5, close to 1066, not quite).

Just a curious thought, and wondered if anyone had tried that before.

I want to be your Opteron... Why don't you call my name - Peter Gabriel?

More about : latency bandwidth

May 7, 2002 12:35:50 AM

Lantency is reduce for all memory due to less lantency from Cpu--MCH by using PC1066 you reduce latency from RIMM---MCH

Increase in FSB will do more read but not write (at lease on RDRAM)
Increase in frenquency improve read/write

cheap, cheap. Think cheap, and you'll always be cheap.AMD version of semi conducteur industrie
May 7, 2002 12:37:02 AM

Well Latency is mesured in clock cycles (CL and a buncha others... look in the BIOS) and Bandwidth is also with clock cycles... the only reason you would get increase only from bandwidth is with dual channel... but im not sure on this, just a speculation. Anyways a clock increase to the ram should increase performance because of the smaller latency and the higher transfer... so there :p 
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May 7, 2002 7:32:25 PM

Quote:
Anyways a clock increase to the ram should increase performance because of the smaller latency and the higher transfer

My question was, which one of these does the P4 draw more benifit from when moving to a 133 FSB?


I want to be your Opteron... Why don't you call my name - Peter Gabriel?
May 7, 2002 10:56:03 PM

Clock cycle only when internal.

cheap, cheap. Think cheap, and you'll always be cheap.AMD version of semi conducteur industrie
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