[rescue] RE: SGI vs. Sun

[Janet L. Campbell]

On Fri, 14 Jan 2005, Curtis H. Wilbar Jr. wrote:

> Amazingly nobody here has mentioned the U5/U10 cpu cache.  some
> processors have 256K cache... others 2M of cache....  in my
> limited U5/U10 experiences, the 2M processors outperform the others
> hands down in almost everything.  Even if the 2M cache processor
> is a slower one than the 256K cache processor being compared with.

Bus speed is also an important consideration.

The older UltraSparc-IIi CPUs were the Sabre series, and have a 3x bus
multiplier.  This meant that the 270MHz/256KB CPUs ran a 90MHz UPA bus,
the 300MHz/512KB CPUs ran a 100MHz UPA bus, 333MHz/2MB 111MHz, and
360MHz/2MB 120MHz (the peak for the U5/U10 design).  These usually have
heatsinks that look like a grid of vertical "pins".

The newer UltraSparc-IIi CPUs (Sapphire) have a 4x bus multiplier.  The
360MHz/256KB runs a 90MHz UPA, the 400MHz/2MB runs at 100MHz, and the
440MHz/2MB at 110MHz.  SME was going to release a 480MHz/2MB IIi module (I
have the docs) but it got canceled at the last minute.  I'm not sure if it
was a yield or a marketing issue, most of the 440's I've had have handled
being clocked to 480 without incident.  The Sapphire CPUs usually have a
"blade" style heatsink.

prtdiag will show bus speed(s).

-Janet