Adding RAM

Gabriel Dragffy dragffy at yandex.ru
Wed Nov 15 09:51:35 UTC 2006


It would seem to me that the article at: 
http://www.pcguide.com/ref/mbsys/cache/char_Cacheability.htm
holds water, however it would appear dated and obsolete, I quote:

	"Pentium Pro PCs use an integrated level 2 cache that contains the tag
RAM within it, so none of this is really a concern for these machines.
The Pentium Pro will cache up to 4 GB of main memory,"

Pentium Pro WAS a high-spec pentium, before the PII.

	"The Pentium II uses an SEC daughtercard. It has the same general
architecture as the Pentium Pro, but due to a design limitation will
"only" cache up to 512 MB"

We're now on to quad-core PIVs so I think it would be safe to say that
restriction has been alleviated.



On Fri, 2006-10-13 at 22:55 +0100, Tony Arnold wrote:
> On Sat, 2006-10-14 at 04:23 +0800, Wei-Yee Chan wrote:
> 
> > > Too little internal cache makes the chip unable to handle large
> > > amounts of RAM? That doesn't sound right to me. But I'm not a CS
> > > major, so that actually might be the case. Can someone confirm 
> > I cannot confirm that your problem is due to this, but there is a
> > possibility that it could be.  Have U tried removing one of the strips?
> 
> I'm not convinced of this! The amount of cache you need surely depends
> on the access patterns of data/code in main memory and should not be
> dependent on the amount of physical memory.
> 
> As I understand caching, every time the processor tries to get a the
> contents of a location in memory it checks to see if the contents of
> that location has been cached. If not, it goes to main memory and puts a
> copy in the cache, if yes, then it gets it from the cache which is much
> faster than main memory. Hence frequently access locations stay in
> cache. Also, loops of code that can all fit in cache will run much
> faster than loops that do not fit.
> 
> Regards,
> Tony.
> -- 
> Tony Arnold, IT Security Coordinator, University of Manchester,
> IT Services Division, Kilburn Building, Oxford Road, Manchester M13 9PL.
> T: +44 (0)161 275 6093, F: +44 (0)870 136 1004, M: +44 (0)773 330 0039
> E: tony.arnold at manchester.ac.uk, H: http://www.man.ac.uk/Tony.Arnold
> 





More information about the ubuntu-users mailing list