Date   : Fri, 31 Jul 2009 19:36:15 +0100
From   : zeem.uk@... (Alex Taylor)
Subject: Units of memory, Was: Master Ethernet upgrade

2009/7/31 Rob <robert@...>:

> Check your BIOS ... I've got an early P4 that the bios allows you to
> turn hyperthreading off and on. ?Off, you get a single CPU that runs
> at twice the speed. ?On, you apparently get two processors .. ?I've
> never quite worked out which mode is best,apart from "single threaded"
> applications which definitely run faster when HT is off, as they are
> not limited to 50% of the total speed..

I'm pretty sure that's not true. There's a small performance hit on
HT-capable P4 processors in certain applications, due to the way the
P4 works, but it's not because HT divides the CPU into two units of
half the speed each.

-- 
Alex Taylor