From: Benjamin Koh (benkoh_at_leland.Stanford.EDU)
Date: Tue Mar 02 1999 - 13:23:30 EST
The HX chipset is for desktop Pentiums ie big, hot and power hungry. No
current Thinkpads use the desktop chips, so no thinkpads use the HX
chipset either, meaning all Pentium Thinkpads can't cache above 64 MB.
Possible exception: I don't know if the P90/120 760s use mobile or
desktop chips.
Some ancient Taiwanese clones do use the HX chipset and desktop CPUs,
but I think the trade-off in heat isn't worth it - taking 2 seconds less
to do something is not worth frying your thighs for. Anyway if you
really need speed you should be moving up to Pentium II by now, which
doesn't have the 64 MB limit.
Remember that if your hard disk is getting a lot of use, any RAM, no
matter how slow, is 2,000-5,000 times faster than a hard drive. Access
time is in nanoseconds (10^-9) vs milliseconds (10^-4).
Bottomline: if your system does a lot of disk swapping, buy the RAM.
Benjamin
John Kim wrote:
>
> On Tue, 2 Mar 1999, Vincent Poy wrote:
> >
> > Actually, everyone is incorrect about this... The 64 meg issue
> > has nothing to do with the OS but the chipset implementation on the
> > system.
>
> Those chipsets limited to caching 64 MB cache it from the
> bottom up. If the OS uses memory from the top down, it will
> be using uncached memory before it uses cached memory. That
> is why some OSes can be mostly unaffected by the problem,
> while others are severely impacted. One oft-cited remedy is
> to turn the uncacahed memory into a ramdisk, but I've never
> seen details on how that is done.
>
> > If it's the Triton FX/MX/TX/VX, the system can only cache 64 megs
> > of RAM. If you go over, none of the ram will be cache. If you use the HX
> > chipset, then it can cache 512 megs of RAM.
>
> Which just begs the question: which Pentium laptops use the
> HX chipset, if any?
>
> --
> John H. Kim
> kim_at_stormhaven.org
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