Saving performance to different drive (hard drive, SATA SSD, M.2 SSD)

I did a saving test, to continuously append data into a exist .mat file. I tested the code using:

1. 7200 rpm hard drive. 2. 850 EVO, SATA ssd. 3. 960 EVO, M.2 ssd.

the speed of my CPU is 3.0 Ghz, the speed of memory is ddr3 1600Mhz.

the result is: 90 seconds, 82 seconds, 80 seconds, respectively.

This is a little werid because as we know, SSD should have a significantly faster writing speed than hard drive, and the M.2 ssd should be much faster than SATA SSD.

but what I found in the test result, is that, the difference between hard drive and SSD is only about 10%, and the difference between SATA ssd and M.2 ssd is almost negligible.

just want know if there is any reason here, or if there is anyway to improve the performance.

below are the test code:

    tic
    test1=1;
    save test1 test1
    for i=1:1:1000
        fprintf('%0dth data.\n',i)
        eval(['tmp',num2str(i),'=1:1:2e5;'])
        eval(['save(','''','test1','''',',','''','tmp',num2str(i),'''',',','''','-append','''',')'])
    end
    toc

Thanks!

Yu

[Andres Salazar]

I have a toshiba THNSN5512GPUK NVMe

16GB ddr4

Intel core I7 7th gen

NVIDIA GPU GTX 1050

It took 299.21 seconds

[Jan]

Is there any reason to use eval? This might be the bottleneck of the code such that the speed of the disk is less relevant. In addition appending a variable to a MAT file requires to parse the MAT file at first, wuch that there is a huge overhead. If this overhead is 78 seconds on your machine, that times for writing would be: 22 sec, 4 sec, 2 sec. This might be realistic.

I think your code is not usful to measure the disk access performance.