Re: [ON TOPIC] HELP: Getting lousy memory throughput from Abit KD7

Date: Tue Jul 22 2003 - 14:53:50 EST

On Tue, 22 Jul 2003 15:34:51 EDT, "Richard B. Johnson" said:

> If I needed to really find the memory access time, I would write
> a program to test it.

> (4) Warm the cache first by reading everything in the buffer you
> are going to test.

At which point you're measuring the cache speed not the memory speed.

> You will probably be amazed at how well your system performs. This
> dual CPU 400 MHz thing, with 100 MHz memory does 1,900++ MiB/sec.

Which probably explains this result. Do a quick sanity check - this number
seems to indicate 20 bytes per memory clock, EVERY clock - either there's
some VERY creative use of prefetching to make sure that you never hit a
cache line miss, or you're measuring the cache.. ;)

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