Hello Lee,
On Tue, 23 May 2000, Lee Elliott wrote:
> Hello list(s),
>
> Just something I noticed after setting up an x86 system after running
> Debian on m68k.
>
> The m68k system was an Amiga with an m68060/50MHz which gave a BogoMIP
> rating of 99.something. The x86 system is a dual PIII 650MHz system and
> it rates as 2600 BogoMIPs. This would seem to imply that on a per MHz
> basis, the m68060 is the equivalent of two PIIIs.
This is right.
AFAIK, the hardware side of the issue goes something like this:
One phase of the clock signal looks something like this:
Voltage
high ____
| | |
low | |____|
The x86 Processors will issue a command whenever the signal voltage is
high. The m68k processors will issue a command whenever the signal voltage
is high and the next when it's low (Motorola claims, that the 68060
issues three commands per clock cycle, I don't know why you then don't get
three times the MIPS value of a x86 on a per MHz basis. I also don't
know if the above mentioned holds true for Pentium and upwards. But it
holds true for 386 and 486). This is why a m68k processor is on a per MHz
basis really twice as fast as a x86 processor.
Regards,
Daniel
