[Tfug] Intel CPU compatibility

[Bexley Hall]

Hi, Ron,

--- On Tue, 6/3/08, Ronald Sutherland <ronald.sutherland at gmail.com> wrote:

> From: Ronald Sutherland <ronald.sutherland at gmail.com>
> > I want to upgrade the processors in my SGI VWS.
> > IIRC, it is currently configured as 1x450 (or maybe
> > 2x450?).
> 
> On all my computers the CPU is the fastest part in the
> system they are well
> over 10x the data bandwidth of most anything else (i.e. CPU
> to cache
> bandwidth is huge). If I put a CPU that runs 10 times
> faster in those
> computers, it will then run 100x faster than the rest of
> the system, and I
> will add not much more than 9% increase to the bottom line
> performance
> (except the programs that can run only in cache).

Yes, that's probably true for most computers  :>
But, the VWS is not a "typical" computer.
For example, the memory (i.e. *main* memory) bus
bandwidth is 3.2GB/sec.  Not too shabby for a 10 year
old machine!  :>

Disk I/O is probably the slowest part of the system.
The HBA can support 160MB/s transfers though the PCI
bus that supports it is the bigger part of the problem.

But, the machine is designed for processing digital audio
and video.  As a result, the disk just needs to be fast
enough to stream video at "real-time" rates.  Even with
400MHz CPU, I can still manipulate incoming video in
real time (and display it).  But, not much beyond that
(it takes a fair number of MIPS to actually *alter*
video content while viewing it).

So, the upgrade to 800MHz CPU's will probably *truly*
double my performance (in terms of the size video window
that I can manipulate in real time).

Note that this is also true of 3D CAD applications -- as
long as you can keep the design in main memory and not
thrash.

As a "general purpose" machine, <shrug> better to buy
something newer.  But, for *these* purposes, it does quite
a nice job!

--don