Impossible Results

[computerquip-streamlabs]

I used the win64 prebuilt binaries ( found here: https://panthema.net/2013/pmbw/pmbw-0.6.2-win64.zip ) to create a graphical benchmark of my systems memory bandwidth. The results are quite impossible unless I'm misreading them.

Below is the PDF generated using the provided gnuplot (sorry about the third-party host): https://www.docdroid.net/VWgo3pw/plots-mors.pdf.html

In some of these graphs, it labels a memory bandwidth of over 200 GiB/s. The best I can figure, the conceptual top speed should be around 22 GiB/s, almost a tenth of what's being reported.

PC information (provided by CPU-Z): https://hastebin.com/vuwixakixe.sql

[lorenzhs]

If you look at the array sizes for which you get these speeds, it becomes clear that those sizes entirely fit into cache, and that pmbw measures cache speed. But cache is much faster than RAM, so the measurements are correct, you're just misinterpreting them. If you want figures for RAM, look at the large instances (25/26 and more on the x axis on your machine).