What determines computation speed in MatLab?

For example, running the cwt function on a large matrix takes my computer >12 mins and once it even crashed. I know RAM determines how large you can make an array. What about speed of processes? CPU single-core clock speed? My specs are on a 2017 Macbook Air 8 GB RAM 1.8 GHz dual core intel i5

Answer 1

[John D'Errico]

What determines computation speed? A huge number of things.

Try running bench on your computer. It looks at a many computations with all sorts of characteristics. Large scale linear algebra is very different from pure display of graphics. If you have a large amount of cache memory, then your computer needs to go into slower memory less often. Multiple cores are great for some problems, but useless for others. If your computer is memory limited, then it will be using virtual memory more often. It may run into memory limits.

MATLAB does often try to use multiple cores, if you have them, but not all computations allow that. A SSD (solid state drive) is better than an old style spinning platter. (And it runs cooler too.)

A good fan can be terribly IMPORTANT. That laptop can easily overheart if you are doing a large computation flat out. And if it does, then your CPU will be smart. It will slow down the CPU clock speed! And that helps your computer to cool down, but it hurts your speed. Otherwise, an overheated CPU is not a happy CPU. You certainly don't want it on your lap. So one thing you can do is to buy an external fan. We used to use one for an older laptop that was having overheating problems. It sits underneath your computer, and cools the thing down.

[Anas Khan]

Thanks! The bench really helped. It definitely gets hot and the fan gets going pretty good. I'm going to upgrade I guess.

[John D'Errico]

No matter what you do, problams always expand to meet the available computing capacity. :) A basic rule of computing.

I've got an iMac with an i9 in it, with 8 cores. I can get it cranking pretty hard, and when it does, my system fan kicks on high.