Ubuntu 11.10 Beta 2 (Oneiric Ocelot) Released

Liam Proven lproven at gmail.com
Sun Sep 25 01:45:31 UTC 2011


On 24 September 2011 23:06, Ric Moore <wayward4now at gmail.com> wrote:
>
> When I jammed my new motherboard with 6 AMD cpu's and 16 gigs of ram, 32bit
> Ubuntu ran just fine by merely plugging the harddrive back to the new
> motherboard,  with the correct kernel ...which I pre-loaded up in advance.
> But, as soon as I got my DVD, I loaded 64 bit and it really rolls better.
> So, as Basil noted, the "broad-based" answer is with a 64bit CPU, less-than
> 4 gigs of ram, go 32bit. 4 Gigs or better, go 64bit. Just as a rule-of-thumb
> mind you. YMMV, as always. Ric

The other thing to note is 64-bit code optimisation.

Compared to other CPU ISAs such as PowerPC, SPARC and so on, x86 is
notoriously register-starved. It only has 8 available - the more than
40 year old IBM System/36 had 4 times that many! Examples for popular
architectures are here:
http://en.wikipedia.org/wiki/Processor_register#Some_examples

x86-64 has double the number of registers, so starvation is less of an
issue. Thank AMD for this - it invented x86-64, Intel only later and
reluctantly copied it when Itanium failed to take off. Intel was going
to do its own, different, incompatible 64-bit extended instruction set
but Microsoft told them not to be stupid and that MS would only
support 1 64-bit x86 ISA and it already was doing: AMD's AMD-64. So
Intel licensed x86-64 from AMD and copied it.

So, code compiled for 64-bit runs faster. It takes a little more
memory - well, in a few places, twice as much, obviously, but not in
all that many places and RAM is cheap these days.

But going 64-bit gives you more benefits than just >4GB accessible RAM
and larger maximum process sizes. It also means that /very/
CPU-intensive code can run 30% or more, mainly because of those extra
registers.

I've been running 64-bit since 9.10. No real problems. Flash was a
little flakey at first - although it did work - but it's been fine for
a year or more now. Nothing else at all.

-- 
Liam Proven • Info & profile: http://www.google.com/profiles/lproven
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