Re: CPU questions...

Alex wrote:

Hi Everyone,

I'm building a new Linux workstation for my home (WOOHOO!) and have
chosen to run with the ABIT IP35 Pro LGA 775 Intel P35 ATX Intel
Motherboard, but I have a question about which processor would work
best...

An AMD... :p

First off, is hyper threading support in Linux worth worrying about?
IBM has an interesting site talking more about this -
http://www-128.ibm.com/developerworks/linux/library/l-htl/ - and from
their benchmarks it looks like it's not a huge factor.. but just
curious what others think.

As other posters have already mentioned, hyperthreading was implemented on
some (but not all) of the Netburst-generation of Intel processors to
overcome the performance hit associated with the long pipelines of that
architecture.

Basically, the processor takes two threads at once, just as if it were two
processors or two cores on one processor, but still it will execute only
one at the same time, with the second thread being processed whenever the
first thread is on hold, e.g. because it is waiting for input from another
thread. To the operating system, a hyperthreaded processor appears as if
it were two physical processors - or at least, from the user point of view,
as the 2.6 Linux kernel generation is capable of distinguishing between
multiple physical processors, multiple cores on the same processor and
multiple hyperthreads within a core, so as to more efficiently balance the
load and more evenly distribute heat.

Hyperthreading does have its advantages. Sun's UltraSPARC T1 processor has
8 cores on one chip, each of which has four hyperthreads. The general
consensus is that - management overhead with regard to multithreading
included - a processor (core) with two hyperthreads performs at about 130%
compared to a singlethreaded processor (core).

That said, the highest degree of performance in symmetric multiprocessing
systems seems to come from so-called ccNUMA systems, i.e. systems in which
there is more than one physical processor chip and more than one memory
controller, with each memory controller and its associated memory linked to
one or multiple processors. This is how an AMD multisocket machine works,
and also how mainframes work.

Secondly, any thoughts on shared vs dedicated L2 cache? I found this
site - http://www.digit-life.com/articles2/cpu/rmmt-l2-cache.html -
which benchmarks shared vs dedicated cache, and as with the hyper
threading benchmark, it doesn't really show much difference... but
again, I'd like feedback from others on if one is suggested over the
other.

There is more to consider than just benchmarks when it comes to shared
versus dedicated cache. There is also a phenomenon such as cache pollution
or cache snooping, which forms a potential security hazard. Separating
data cache from instruction cache makes it harder for malicious code to
harvest sensitive information from cache.

And finally, Xeon vs Pentium... Newegg's prices on the two aren't too
different, so if I can get my hands on a dual-core Xeon processor, for
example Intel Xeon 3065 2.33GHz LGA 775 65W Dual-Core Processor Model
BX805573065 (Currently $180 on NewEgg) vs Intel Core 2 Duo E6750
Conroe 2.66GHz LGA 775 65W Dual-Core Processor Model BX80557E6750
(also $180 on Newegg), would the Xeon be worth running with out of the
two?

A Xeon is more or less the same thing as its consumergrade counterpart but
is geared more for stability and throughput. You will typically find Xeons
in Intel x86-based servers and workstations because they are deemed more
reliable. I guess it all depends on what you want to do with the system.

Still, if you want my personal opinion, go for AMD. ;-) They are more
energy-efficient and more affordable than Intel - Intel's idea of boosting
performance is raising the clock speed while AMDs are simply more
efficiently structured - and ethically you'd be supporting a company that's
_not_ in league with The Evil Empire. (Intel and Microsoft are involved in
the Trusted Computing Platform, a DRM-ridden monstrosity that could end up
being the PC that you simply can't install anything other than Windows
on...)

Thanks for any feedback or suggestions. The system I'm building will
be used for not only day-to-day computer use (desktop publishing,
general Internet use, etc), but also video editing with Kino and
Cinelerra, graphics editing with TheGimp, and if I can find the time
to learn it, working with Blender. And it'd be nice to have a system
that truly shows off the latest eyecandy of Compiz/Beryl.

Get an AMD-based system, preferably with an AMD/ATi chipset or an nForce
chipset - there have been difficulties with Via chipsets in the past with
regard to (local) APIC support.

Oh, and one more question ... this mobo along with most newer ones use
SATA as opposed to IDE. I have a TON of IDE drives, so is there a
simple way to connect an IDE drive to a SATA HD controller? And if
so, any performance hits doing this?

As others have already mentioned, Promise cards are well-supported, but you
should also keep in mind that most new motherboards still do come with at
least one IDE/PATA channel, which lets you connect two IDE devices.

--
Aragorn
(registered GNU/Linux user #223157)
.

Relevant Pages

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