CPU related performance

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CPU related performance

Postby Robert Wilding » Fri Dec 18, 2009 12:06 pm

Hi,

I am looking at buying a new pc.

Can anyone tell me if Ffenics will run faster on an i7 or quod core CPU than a single core with the same clock speed (does it utilise the entire quad core)?

What kind of performance could one expect running 64 bit opposed to 32 bit?

Thanks

Robert
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Re: CPU related performance

Postby Graham Smith » Fri Dec 18, 2009 1:34 pm

Save your money. To quote Ian "Gizmo" Richards, a technical guru, "Overall, the results confirm that the performance of individual programs is not predictably improved by the use of multicore processors unless the application has been optimized specifically for use on multicore PCs." The same is true of 64bit operating systems.

You will find very little, if any, advantage to quad core processors and 64bit operating systems UNLESS you have a specific need for a machine that will run certain heavily CPU intensive software. On one end of the spectrum this would be business programs like Autocad and on the other it would be for some heavy duty games.

So, there does not seem to be any real advantage to a quad core without the 64bit version of Windows and there are a lot of programs that won't run on that, so why bother.
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Re: CPU related performance

Postby GordonCopestake » Fri Jan 08, 2010 12:18 pm

One thing to keep in mind regarding multi-core CPU's is that whilst Ffenics wont run any faster on a multi-core CPU compared to a single core CPU, it does mean that other programs running at the same time MAY run faster. If you multi-task on the machine heavily then the extra cores might come in handy. E.g. if you are running a large report in Ffenics that eats 100% of your single core CPU, your Excel spreadsheet will slow to a crawl. On a multi-core CPU the one core will run Ffenics and any others will run other programs.

If your machine is dedicated to Ffenics, then as Graham says, there is no advantage so save your money.
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Re: CPU related performance

Postby benjji » Fri Jan 08, 2010 3:31 pm

GordonCopestake wrote:On a multi-core CPU the one core will run Ffenics and any others will run other programs.

Off Topic

how do you go about assigning different programmes to different cores ?
or is it all done by the 'magic of Windows', and a user has no say in what runs where
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Re: CPU related performance

Postby GordonCopestake » Fri Jan 08, 2010 3:35 pm

You can assign "affinity" through task manager by right clicking on a process and hitting "set affinity"...

However I've found that it's best to leave it to the "magic of windows" (otherwise called the scheduler)
http://en.wikipedia.org/wiki/Scheduling_(computing)
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Re: CPU related performance

Postby Graham Smith » Sat Jan 09, 2010 2:01 pm

GordonCopestake wrote:One thing to keep in mind regarding multi-core CPU's is that whilst Ffenics wont run any faster on a multi-core CPU compared to a single core CPU, it does mean that other programs running at the same time MAY run faster.

I probably was not as clear as I should have been. Dual core CPUs have become pretty standard and it is well established that Windows will benefit from being run on one. It's the quad-cores that are at issue.

Most of the objective tests I have seen over the past couple years say that (for 32bit Windows) you are better off buying a faster Dual Core than a slower Quad Core. Here an example:
... only rendering and encoding tasks exploit parallelism enough to overcome the 25% speed deficit between the dual and quad core CPUs. Outside of that specific niche, performance will actually suffer for most general purpose software if you choose a slower quad-core over a faster dual-core.

IOW, for most users, a 32bit version of Win7 running on a decent DualCore CPU with 4GB of RAM will do as well or better than a 64big version of Win7 running on an average QuadCore with 6GB of RAM.

As an aside, you will often get the most bang for your buck with a mid-price-range DualCore CPU and a separate graphics card.
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