«

On Tue, 17 Aug 2010 14:37:17 -0700, AD. wrote:

>> >> How many simultaneous threads is that application designed to use?
>>
>> > What application? Nobody mentioned an application.
>>
>> "and my main concern (apart from price) is speed of execution of code
>> that uses multiple processors (OpenMP)."
>
> So? You're still jumping to conclusions.

Nope. simply asking a question.


> OpenMP is a programming API for SMP code. Nothing about using an
> application or specific workload there.

So?

How well the machine will work for him ultimately will depend on what
specific software he will be running on it. It will need to be multi-
threaded if it is to benefit from using more than one core in a multi-
cored CPU.


--
"Filtering the Internet is like trying to boil the ocean"

On Tue, 17 Aug 2010 14:48:33 -0700, AD. wrote:

> Also it really depends on the actual workload which chip ends up faster.

Thank you - you've said the same as what I said. It all depends on what
software will be used on the machine.


--
"Filtering the Internet is like trying to boil the ocean"

Sweetpea wrote:
> On Tue, 17 Aug 2010 17:52:51 +1200, Gib Bogle wrote:
>
>> I am about to buy a computer that I'll use for working, and my main
>> concern (apart from price) is speed of execution of code that uses
>> multiple processors (OpenMP). I'm looking at the Dell Precision T3500,
>> with the Xeon E5630 quad core 2.5 GHz, but I'm not sure that this would
>> actually be faster than a 2.8 GHz
>> Core i7 quad-core system, which I think would be cheaper. I do not
>> run games. Anybody have any experience that might help with this
>> decision?
>
> How many simultaneous threads is that application designed to use?
>
> If only 2 then you'll be wasting your money going to a 4-core system.
>
> Answer that question and you'll probably have answered your own
> question.
>
>

I don't understand your comment. Both systems are quad core. My code (written
by me) can use all 4 cores.

Sweetpea wrote:
> On Tue, 17 Aug 2010 14:37:17 -0700, AD. wrote:
>
>>>>> How many simultaneous threads is that application designed to use?
>>>> What application? Nobody mentioned an application.
>>> "and my main concern (apart from price) is speed of execution of code
>>> that uses multiple processors (OpenMP)."
>> So? You're still jumping to conclusions.
>
> Nope. simply asking a question.
>
>
>> OpenMP is a programming API for SMP code. Nothing about using an
>> application or specific workload there.
>
> So?
>
> How well the machine will work for him ultimately will depend on what
> specific software he will be running on it. It will need to be multi-
> threaded if it is to benefit from using more than one core in a multi-
> cored CPU.
>
>

Of course it's multi-threaded - OpenMP.

On Wed, 18 Aug 2010 10:49:39 +1200, Gib Bogle wrote:

>> How many simultaneous threads is that application designed to use?
>>
>> If only 2 then you'll be wasting your money going to a 4-core system.
>>
>> Answer that question and you'll probably have answered your own
>> question.
>
> I don't understand your comment. Both systems are quad core. My code
> (written by me) can use all 4 cores.

So it is designed to use at least 4 threads.


--
"Filtering the Internet is like trying to boil the ocean"

Dave Doe wrote:
> In article <i4d83j$dik$>,
> says...
>> I am about to buy a computer that I'll use for working, and my main concern
>> (apart from price) is speed of execution of code that uses multiple processors
>> (OpenMP). I'm looking at the Dell Precision T3500, with the Xeon E5630 quad
>> core 2.5 GHz, but I'm not sure that this would actually be faster than a 2.8 GHz
>> Core i7 quad-core system, which I think would be cheaper. I do not run games.
>> Anybody have any experience that might help with this decision?
>
> Go for the i7 - they're good - fast and cheap (for such speed) at around
> $450. Great desktops. Are you going to take advantage (and spend a lot
> of extra $) of the Xeon features? (you building a server?). Hence, IMO,
> the i7 for a single processor desktop machine.
>
> If you find a CPU comparison you'll find the 860,70 and the other
> chipset one, right up there.
>

No, I am not building a server. The only reason I started considering the Xeon
system is that where I work we get a good discount on the Dell T3500. I'm
thinking that I might be better off just getting a no-name system put together
with a good mobo and the i7.

Lawrence D'Oliveiro wrote:
> In message <i4d83j$dik$>, Gib Bogle wrote:
>
>> I'm looking at the Dell Precision T3500, with the Xeon E5630
>> quad core 2.5 GHz, but I'm not sure that this would actually be faster
>> than a 2.8 GHz Core i7 quad-core system, which I think would be cheaper.
>
> As I understand it, Xeon chips are intended for use in servers, with
> diagnostic and management capabilities oriented towards that use. So the
> question is whether you need such capabilities or not.

No, I don't want server capabilities, just raw speed.

EMB wrote:
> On 17/08/2010 5:52 p.m., Gib Bogle wrote:
>> I am about to buy a computer that I'll use for working, and my main
>> concern (apart from price) is speed of execution of code that uses
>> multiple processors (OpenMP). I'm looking at the Dell Precision T3500,
>> with the Xeon E5630 quad core 2.5 GHz, but I'm not sure that this would
>> actually be faster than a 2.8 GHz Core i7 quad-core system, which I
>> think would be cheaper. I do not run games. Anybody have any experience
>> that might help with this decision?
>
> The Xeon has more L2 cache, but the i7 has a higher turbo-boost mode.
> Overall I would expect the Xeon to be faster, but I'm unsure you'll ever
> notice the difference in the real world - most of what you pay for with
> the Xeon is support for ECC memory and multiple CPUs.

I don't need the multiple CPUs or ECC memory, so all other things being equal
I'll be paying a premium for the Xeon. I'm going to try to benchmark two
systems with my program - if I can find computers to test on.

On Aug 18, 9:55*am, Sweetpea <Herit...@Sweetpea.com> wrote:
> On Tue, 17 Aug 2010 14:48:33 -0700, AD. wrote:
> > Also it really depends on the actual workload which chip ends up faster..
>
> Thank you - you've said the same as what I said.

Huh? You jumped to conclusions and made a specific statement that said
a quad core would be wasted if the application only uses 2 threads.

You ignored the possibilities that there is probably more than one app
running, the OS or other background tasks could require some CPU, the
user might want to do something else while "the app" is running, or
that "the app" doesn't also use multiple processes etc etc.

> It all depends on what software will be used on
> the machine.

BTW - different workloads using the same software can result in very
different performance. It's more than just what software is being
used.

--
Cheers
Anton

On Wed, 18 Aug 2010 11:05:27 +1200, Bret wrote:

> On Tue, 17 Aug 2010 22:55:41 +0000 (UTC), Sweetpea wrote:
>
>> On Wed, 18 Aug 2010 10:49:39 +1200, Gib Bogle wrote:
>>
>>>> How many simultaneous threads is that application designed to use?
>>>>
>>>> If only 2 then you'll be wasting your money going to a 4-core system.
>>>>
>>>> Answer that question and you'll probably have answered your own
>>>> question.
>>>
>>> I don't understand your comment. Both systems are quad core. My code
>>> (written by me) can use all 4 cores.
>>
>> So it is designed to use at least 4 threads.
>
> You mean 8 ?

4 cores.


--
"Filtering the Internet is like trying to boil the ocean"