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Simulation time does not scale with processor

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Hello all,

Just as a preface, I do not have significant experience with Comsol in general, and the bulk of my manipulations are occurring within Matlab, but my question is of a general sort.

I am running simulations in Comsol, though Matlab, of a two dimensional silica wedge with azimuthal symmetry at various radii for the purpose of obtaining the form of the mode profiles and various properties related to loss, dispersion, etc, within with wedge for an arbitrarily sized ring resonator.

The Matlab code that I'm using to run the simulation simply controls the inputs into Comsol, and does not do any real computation itself.

My situation is this:
I had previously been running the simulations on a laptop with an i7-2720QM (quad core) CPU which CPU-Z shows clocking up at 3GHz, and has 8GB of RAM.

I recently built a new computer with an i7-4930K (hex core) which clocked out of the box to about 3.7GHz, and I further OCed to 4.4GHz. It has 32GB of RAM.

In both cases, Comsol is not using all of the RAM, since each individual simulation isn't very big (it takes 30-60 seconds to complete), I just have to do a lot of them back to back.

Both machines are running Comsol 4.4 and a 64-bit OS, the laptop is Windows 7 with Matlab R2011a, and the desktop is Windows 8.1 with Matlab R2014a.

Even straight out of the box, the new CPU should be about 2.5-3x more powerful than the laptop CPU in terms of simply cores and clock speed (in reality it scales even higher). However, the speed at which it runs the simulations was only about 25% faster. Furthermore, after I overclocked the CPU, the speed of the simulations scaled almost perfectly with the increased clock speed, becoming about 50% faster than the laptop overall.

So essentially, my issue is that the simulation speed scaled horribly with the switch to a more powerful processor, but perfectly with the clock speed of the processor itself.

I should also add that I monitored the total CPU usage during runs for both cases, and for both machines, Comsol consistently made use of 50-60% of the processing power during computation, so it is not as if the new chip just isn't being utilized effectively.

I apologize if I have not provided sufficient information, and if more specifics on the simulation itself are required, I can try to obtain them from the person who wrote it.

Is there any particular reason for the speed to scale so horribly, such as bad support for Ivy-E chips?

Any and all insight is appreciated.

0 Replies Last Post Apr 10, 2014, 4:40 p.m. EDT
COMSOL Moderator

Hello David Sell

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