help me make decision about purchasing/building a computer..

Jean-David Beyer · External Since: Jul 02, 2006 Posts: 444

Baho Utot wrote:

> Well I bought a Dell Insperion 1501 notebook with AMD turion x2 with 1 GB
> ram and 120MB HD for 800.
>
> So far I have had the cpu usage go past 50%.
>
So what? My machine has two hyperthreaded processors, so it looks like four
processors, and they all run at almost 100% This does not prove anything
other than I can find four compute-limited jobs to run. Mine run at nice 19
and they absorb all the cpu time not otherwise used by more important
processes. What is important is not whether or not the processors are fully
utilized, but whether a process you care about can get enough processor time.

14:24:32 up 71 days, 16:57, 3 users, load average: 4.17, 4.20, 4.11
127 processes: 121 sleeping, 5 running, 1 zombie, 0 stopped
CPU states: cpu user nice system irq softirq iowait idle
total 4.9% 90.7% 4.0% 0.0% 0.0% 0.0% 0.1%
cpu00 8.7% 84.8% 5.8% 0.1% 0.0% 0.0% 0.3%
cpu01 8.5% 85.7% 5.3% 0.0% 0.0% 0.0% 0.3%
cpu02 0.1% 98.3% 1.4% 0.0% 0.0% 0.0% 0.0%
cpu03 2.2% 93.8% 3.7% 0.0% 0.1% 0.0% 0.0%

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 14:20:01 up 71 days, 16:52, 3 users, load average: 4.19, 4.23, 4.10

CBFalconer · External Since: Jun 08, 2005 Posts: 661

Baho Utot wrote:
> gort wrote:
>
>> < snipped>
>>
>> Do you think you two could do a bit of editing next time you post ?
>
> What are you talking about?

See the following links.

--
Some informative links:
<http://members.fortunecity.com/nnqweb/> (newusers)
<http://www.catb.org/~esr/faqs/smart-questions.html>
<http://www.caliburn.nl/topposting.html>
<http://www.netmeister.org/news/learn2quote.html>
<http://cfaj.freeshell.org/google/> (taming google)

rossum · External Since: Dec 31, 2006 Posts: 1

On Sat, 30 Dec 2006 18:42:17 -0800, "Mike" <housing2006 RemoveThis @gmail.com>
wrote:

>Hi all,
>
>I need your advice/suggestions on which system to choose/purchase/build in
>order to do high performance computations.

[snip]

Before spending money on hardware you might want to look at your
software again - it is a lot cheaper.

Have you had a good look at your algorithms to see if there is a
faster algorithm available? The college machine should have a
profiler on it (talk to the operators) which will tell you where the
bottlenecks are in your programs.

Have you made your programs restartable? This will allow you do do
the run in pieces at different times rather than an all or nothing
single run.

Can you split up your programs into different ranges? For instance
one program is looking at cases A to F on one computer, another
program is looking at cases G to L on a second computer and so on. If
a program can be multi-threaded then it can often also be split into
different ranges instead, which can sae a lot of time in development.

rossum

General Schvantzkoph · External Since: Dec 29, 2004 Posts: 1207

On Sun, 31 Dec 2006 17:29:39 -0600, A.L. wrote:

> On Sun, 31 Dec 2006 13:47:23 -0800, "Mike" <housing2006.RemoveThis@gmail.com>
> wrote:
>
>>Thanks a lot! That's very nice description. It is very helpful!
>>
>>What motherboard do you recommend then?
>>
>>
>
> I recommend cutting quotes. It has no sense (and is not polite) to
> quote 3 page of trash to add your own 2 sentences.
>
> A.L.

I recommend that you turn on "Mute" in your news reader.

A.L. · External Since: Dec 31, 2006 Posts: 3

On 1 Jan 2007 03:57:25 GMT, General Schvantzkoph
<schvantzkoph RemoveThis @yahoo.com> wrote:

>On Sun, 31 Dec 2006 17:29:39 -0600, A.L. wrote:
>
>> On Sun, 31 Dec 2006 13:47:23 -0800, "Mike" <housing2006 RemoveThis @gmail.com>
>> wrote:
>>
>>>Thanks a lot! That's very nice description. It is very helpful!
>>>
>>>What motherboard do you recommend then?
>>>
>>>
>>
>> I recommend cutting quotes. It has no sense (and is not polite) to
>> quote 3 page of trash to add your own 2 sentences.
>>
>> A.L.
>
>I recommend that you turn on "Mute" in your news reader.

I recomment that you Mute yourself.

A.L.

Mike · External Since: Oct 09, 2006 Posts: 33

>> I recommend cutting quotes. It has no sense (and is not polite) to
>> quote 3 page of trash to add your own 2 sentences.
>>
>> A.L.
>
> I recommend that you turn on "Mute" in your news reader.

General Schvantzkoph,

Happy new year! I just wanna to ask if I also want a 64bit system,

does the Quad-core CPU have that feature?

I hope multi-core and 64bit are not mutually exclusive. To break the
bottleneck of Matlab "out-of-memory" problem, I guess I really need a 64bit
system...

Thanks a lot!

Steve O'Hara-Smith · External Since: Nov 30, 2006 Posts: 7

On 1 Jan 2007 03:57:25 GMT
General Schvantzkoph <schvantzkoph.DeleteThis@yahoo.com> wrote:

> On Sun, 31 Dec 2006 17:29:39 -0600, A.L. wrote:
>
> > I recommend cutting quotes. It has no sense (and is not polite) to
> > quote 3 page of trash to add your own 2 sentences.
> >
> > A.L.
>
> I recommend that you turn on "Mute" in your news reader.

Making the context invisible is counter productive and beside the
point. Not trimming messages wastes bandwidth and storage.

--
C:>WIN | Directable Mirror Arrays
The computer obeys and wins. | A better way to focus the sun
You lose and Bill collects. | licences available see
| http://www.sohara.org/

General Schvantzkoph · External Since: Dec 29, 2004 Posts: 1207

On Mon, 01 Jan 2007 01:17:34 -0800, Mike wrote:

>>> I recommend cutting quotes. It has no sense (and is not polite) to
>>> quote 3 page of trash to add your own 2 sentences.
>>>
>>> A.L.
>>
>> I recommend that you turn on "Mute" in your news reader.
>
> General Schvantzkoph,
>
> Happy new year! I just wanna to ask if I also want a 64bit system,
>
> does the Quad-core CPU have that feature?
>
> I hope multi-core and 64bit are not mutually exclusive. To break the
> bottleneck of Matlab "out-of-memory" problem, I guess I really need a 64bit
> system...
>
> Thanks a lot!

All of the new processors are 64 bit. If you put 4G of DDR2 or more in
your system you'll want to run 64 bit Linux, if you have less than you'll
probably want to run 32 bit Linux. I don't know how Matlab behaves, you'll
have to test that yourself. NCVerilog runs about 30% slower in 64 bits
then it does in 32 bits so I normally run it in 32 bit mode rather than
the 64 bit mode (you can run both 32 and 64 bit binaries on 64 bit Linux).
Matlab is a floating point application so it's possible that it might run
faster in 64 bits then in 32 bits. The 64 bit extensions added more
registers which should speed programs up, however the increased memory
requirements caused by doubling the size of integers and pointers slows
programs down. Matlab mostly does floating point matrix arithmetic
so I'd guess that the effect of the double sized pointers won't hurt it
very much and that the extra registers would more than make up for the
loss that the larger pointers cause. My guess is that Matlab will be a
little faster in 64 bits, but you'll have to make your own measurements.

BTW NewEgg is selling GSkill 2G DDR2 DIMMs for $500 a pair which is about
the same price/Gbyte as the smaller 1G DDR2. You'll need a lot of RAM so
you'll want to use 2G DIMMs which will give you the option of having 8G
in your system. I'm using the GSkill 2G DIMMs in my system, I've just got
4G at the moment, I'll probably put another 4G in next year when the price
for 2G DIMMs fall further.

Chris Uppal · External Since: Oct 14, 2004 Posts: 12

Rob Thorpe wrote:

> But do not underestimate the amount of time that coding
> takes. Coding for multi-processing normally takes longer too, and
> often algorithmic improvements are more helpful than multi-processing.

Coding up advanced algorithms tends to take a comparatively long time
too, and it gets worse if you have to try several of them to find which
(if any) gives a useful performance boost in practise. Exploiting
coarse-grained parallelism is probably the simplest and most
cost-effective way of getting significant performance boosts (assuming
it's possible at all). "Just throw more hardware at the problem", as
they say.

-- chris