Aug 1996 17:20:56 GMT writes:
> : One thing that I haven't seen mentioned is the difference in bus
> : speeds. For example, I can only really afford an Intel P5 100. If I
> : were to get the Cyrix chip with the same clock speed (is it the
> : P120+?) I would only get a 50 MHz bus. Compared to the 66 Mhz I will
> : get with the Intel chip.
> Umm.. not really. The cyrix chip running at 100 MHZ will run off of a
> 33MHz PCI bus and a 66Mhz memory bus, as far as I know.
Nope. This would require a 1.5x clock multiplier, and the Cyrix 6x86 does *NOT*
support this. As the original poster suggested, the 6x86 P120+ (100MHz) uses a
50MHz external bus speed and (on most motherboards) a 25MHz PCI bus speed.
That said, consider that the CPU itself will be faster than an Intel P100. In
fact, the benchmarks used to come up with the P-ratings utilize the entire
computer -- they stress the CPU, memory, disk I/O, video, etc., and are *NOT*
CPU-specific. Thus, the 100MHz 6x86 (the P120+) performs, on the average for
the mix used in the benchmarks, similarly to a Pentium at 120MHz. I'd therefore
suspect that you'd be better off with a 6x86 P120+ than with an Intel P100 for
most purposes, the main exception being FPU-intensive stuff. You'd have to
REALLY stress the I/O systems for the bus speed to make such a difference that
the Pentium 100 would outperform the 6x86 P120+. (Sorry; I've no hard figures
to back this up -- it is admittedly based mostly on reasoning from my
understanding of the benchmarks used to produce the P-values and my
understanding of CPU and bus speeds on PCs.)
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| Rod Smith Author of: |
| http://psych.colorado.edu/~rsmith "OS/2 Soundcard Summary" |
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