cyrix/ibm 6x86MX pr233 really slow...why?
Mark
upgrade my 6x86 p166+, ATI expert@play, VX motherboard, 64Mb EDO, 2 WD hard
drives (~850 +610).
I changed all the voltages etc on my motherboard and set the multiplier to
3*66 (the new chip is actally a 2.5*75 but I believe it can run
equivallently at the 3*66 setting) and yes the chip runs - only really,
really slowly.
I'm at work just now so can't check my jumpers but the BIOS splash screen
reported the cpu as a Cx running at 200MHz - as does Norton utilities 4
sysinfo - but if I run a Norton benchmark I get a pityfully small score
(10.2) c.f. my laptop, an old p75 which gives 15.6 and the standard p166
score of 55ish.
So, any suggestions as to what is going wrong - why is my chip running so
slowly?
(ps it's not just an artifact as programs as well as benchmarks run like
slugs)
Mark
Brian Ballard
the cache is dissabled or something....
Mark <m.g.w...@ncl.ac.uk> wrote in article
<7v6o9s$nul$1...@ucsnew1.ncl.ac.uk>...
Mark
Thanks for the thought.
Possibly there is a cache problem, however the cache _seemed_ to work fine
with the old chip (p166+) the previous evening.
I have a slight complication in that I'm using the TV out on the graphics
card (space restrictions mean that my monitor is in the loft [attic]) and
whilst this is fine for windows and dos I can't see the bios setup screen
(funny refresh rate??). Looks like its a trip up to the roof space for me.
Mark
Brian Ballard <Br...@spam.agamemnon1.demon.co.uk> wrote in message
news:01bf2083$87804bc0$9f81...@cxp252.citymax.co.uk...
hector
but anyways, i had that computer for a year and half. Its a Cyrix 233 just like
yours and it was much faster than my Pentium 166 and Pentium 100 i had
previously owned. I know that your VX motherboard wont support 75mhz. But if i
were you i would defenitley look into buying a new 'cheap' motherboard that
supports 75 mhz, that will really improve your speed. Because in itself, going
from 166 to 233 isnt a big diffrence especially if you have the CPU running at
the same Front side bus speed. So yeah, trust me that Cyrix chip screams but
you need a motherboard for it. VX chipsets are too slow, its YOUR MOTHERBOARD's
fault that it is slow!!
Mark
Thanks for the thought - I agree that 2.5*75 would be much better and I may
get a newer motherboard. My only problem with your suggestion is that the
new cpu was _very_ cheap and as I don't use the machine that much (PII350 @
work and a laptop @ home) to throw more money at my it may not be my best
bet.
The problem which still remains is that the new chip is running _much_
slower @ 3*66 than my old p166+ @ 2*66. The old chip was fine with office
apps and the benchamrk on MDK equated it to a Intel P90 - which seemed fair
enough for games considering the lesser powered FPU of the Cyrix chips.
Regards
Mark
Jason Arthurs
wrote:
>I bought a second hand cyrix/ibm 6x86MX pr233 yesterday and took it home to
>upgrade my 6x86 p166+, ATI expert@play, VX motherboard, 64Mb EDO, 2 WD hard
>drives (~850 +610).
>I changed all the voltages etc on my motherboard and set the multiplier to
>3*66 (the new chip is actally a 2.5*75 but I believe it can run
>equivallently at the 3*66 setting) and yes the chip runs - only really,
>really slowly.
>I'm at work just now so can't check my jumpers but the BIOS splash screen
>reported the cpu as a Cx running at 200MHz - as does Norton utilities 4
>sysinfo - but if I run a Norton benchmark I get a pityfully small score
>(10.2) c.f. my laptop, an old p75 which gives 15.6 and the standard p166
>score of 55ish.
>So, any suggestions as to what is going wrong - why is my chip running so
>slowly?
Here's the score, the Cyrix 6x86MX chips are real power hogs and
require a high current drain compared to Intel or AMD processors.
Chances are your motherboard isn't capable of dealing with this drain
and the voltage regulators are running very hot, in short if the
motherboard documentation doesn't specify 6x86MX (or MII) processors
it probably wont run them.
I had exactly the same problem with three different 6X86MX processors,
a PR233, PR200 (75x2) and a PR200 (66x2.5) the motherboards simply
couldn't supply them with enough current so they ran, but only very
slowly (these were all VX motherboards).
One board however did support the PR200 (66x2.5) fully after a BIOS
upgrade, it was an ABIT IT5V which prior to the upgrade required a
CMOS update on every boot to recognise the processor (which then ran
slowly).
So it's bad news I'm afraid, you'll probably need to upgrade your
motherboard. Second user ABIT IT5H or IT5V are going quite cheap at
the moment and they'll work fine with PR200's (make sure you get a
revision 1.5 (83MHz) or higher board if you want it to work with a
PR233 or MII 300).
Regards,
Jason.
***************
Jason Arthurs ********************************
Bangor * Think like a man of action, *
Gwynedd * Act like a man of thought... *
North Wales ********************************
***************
Mark
Your explanation sounds correct - My motherboard doesn't mention the MII,
I'd just assumed as it supported the voltages and clock speeds the current
would be ok.
Do you think if I underclocked the chip (2.5*66 or 3*60) I'd have any more
luck? I'd heard of overclocked chips needing more volts but the next setting
on my motherboard above 2.93V is 3.38V - probably a wee bit of a jump.
A friend this weekend offered me an Intel p200 for free so all this messing
with the Cryix may be no longer be relevant.
Thanks again for your help
Mark