Re: DRAM to CPU Frequency Ratio (Athlon)

From: Richard B. Johnson (root@chaos.analogic.com)
Date: Fri Aug 04 2000 - 09:47:48 EST


On Fri, 4 Aug 2000, Ookhoi wrote:
>
> Oke, then I do understand the option. So if I have 133MHz capable
> memory, the 4:3 ratio _should_ make a noticeable difference. But it
                        ^^^^^^^_______ Not true at all.

Changing the speed of memory may make a difference if, and only if
the machine is memory I/O bound. When compiling the kernel, your
machine is quite likely disk I/O bound. Most of your time may
be spent waiting for I/O to complete. Any RAM access time is lost
in the noise since it's so small by comparison.

A computing system has many of the characteristics of a low-pass filter.
The dominant pole in the system's transfer function is set by the slowest
device being accessed.

Cheers,
Dick Johnson

Penguin : Linux version 2.2.15 on an i686 machine (797.90 BogoMips).

"Memory is like gasoline. You use it up when you are running. Of
course you get it all back when you reboot..."; Actual explanation
obtained from the Micro$oft help desk.

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