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- Majki Majk
January 25, 2010, 2:34 am
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Hi everyone here and there!
After changing my laptop CPU A50-106 toshiba from celeron 1.7 to
Pentium M dothan 2ghz fsb:400
now laptop works on 600mhz !?!?
as CPUZ is showing 6x multiliers and from the specs of the processor
original is 20x multipliers REAL clock. 2ghz.
I tried to install newer bios but the same. Bios don't have any
options for changing the freqv. ie. clock
Speedswitch, NHC don't help me much as they do provide custom voltage
manual otpions but i don't see freq. options to change from that
RAM is 1GB DDR 333mhz i have changed it from 128+256 PC2100 so now
it's faster in some matter.
what to do? Is it possible to push this laptop to swallow this 2Ghz
processor in real sense using it in all of it's capacity ?
Re: Q: laptop CPU clock
Majki Majk wrote:
It sounds like the original processor was a desktop processor being
used in a laptop. When you install a Mobile processor that actually
supports SpeedStep, it operates at the low speed, until a protocol
is used between the (mobile) chipset and the processor. If you have
a desktop chipset on the motherboard, it is missing things like the
Desktop chipset -------- Desktop processor <--- Your original
If you use a mobile
here, there is no GHI
from the chipset.
Mobile chipset -------- Mobile processor <--- how a more modern
-------- The chipset and the
"GHI" signal etc. have that signal.
See page 60 here, and the description for "GHI". GHI is driven by a
mobile chipset but not a desktop chipset. A mobile processor stays
at "low speed", if mixed with a desktop chipset.
This missing control signal was used to advantage here. People used
to take an SL726 Intel processor and overclock it. For example, the
SL726 is a mobile running 3.06GHz/FSB533. When plugged into a P4C800-E
Deluxe (desktop) motherboard, it would show up as 1.2GHz/FSB400. By
cranking up the input clock, users would run it at 3.6GHz/FSB1200 and
the processor was quite stable under those conditions. That was possible,
because the 875P desktop chipset, nominally a FSB800 chipset, could just
barely run at FSB1200.
The funny thing about that particular hardware hack, is it would
work with a variety of mobile processors. The SL726, being a 3.06GHz processor,
wouldn't need much to run at 3.6GHz. But some even slower processors
give exactly the same response (start at 1.2GHz/FSB400), and can be overclocked
the same way.
So that would be one option for you, but the thing is, your chipset
might actually only be good for a mild overclock, and won't even get
near the performance of the 875P Northbridge. If you had a FSB533 chipset,
it might just barely reach FSB800 before malfunctioning. My guess is,
if the BIOS has the necessary clock input adjustment, you'll be able
to boost the 600MHz/FSB400 to 1200MHz/FSB800, still short of the
proper 2000MHz operating speed. So you'll never get the full speed
that way. You might, if the laptop motherboard had an 875P on it,
but other chipsets are less capable.
You could always modify the GHI signal on the processor socket. But
I don't know if the Intel datasheet gives enough details to build
any necessary circuit for GHI. Page 74 of the datasheet has more
details on the ingredients of SpeedStep.
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