Not able to get all filters to play at DSD512?

[jussi_laako (Jussi Laako (Signalyst))]

I actually tried that last night. Polysinc shrt MP at DSD256 with hyper threading enabled; music paused for first 30 seconds then played and task manager showed 35% cpu usage. I then repeated same as above except hyper threading off, at first music paused then played fine but now task manager showed cpu usage at 63%. Turned hyper threading back on and repeated and task manage reported 33% usage.

If you have a quad-core CPU, make sure you have “Pipeline SDM” enabled - this maximizes the core usage (on a dual-core it just increases overhead and thus has only negative impact). Using “Auto rate family” helps keeping load low as long as the DAC supports DSD also at 48-base rates.

That is correct and as it should, because task manager shows 100% when all cores are at 100%. So if you have HyperThreading enabled on a quad-core CPU and have all the four cores loaded to 100%, but none of the virtual cores loaded, you have exactly 50% load - which practically means HyperThreaded CPU being fully loaded. If you have HyperThreading disabled, then you don’t have those virtual cores, and having all the existing four cores loaded to 100% will also show task manager at 100%.

With HyperThreading enabled it is practically impossible to get the task manager load figure to 100%, because you have only four execution units but eight virtual cores - so every two virtual cores share a single execution unit, but have only register set duplicated to ensure CPU stays busy in cases where you have much more high loaded processes than you have cores (for example because RAM wait states may sometimes put one “thread” on wait because data has not arrived yet from RAM). IOW, CPU can itself “task switch” between the two virtual cores for the same execution unit, if the other of the two needs to wait. This doesn’t really benefit HQPlayer because it really need execution units for doing real work and doesn’t have so many highly active threads. It benefits more the OS itself. OS scheduler understands this and distributes the work to actual cores.

So when you check loads, open Resource Monitor from the Task Manager and switch to the CPU-tab. Then look at the per-core (virtual!) load graphs. If any of the cores maxes out, you likely get a drop-out. Remember that every doubling of sampling rate at least doubles the CPU load! So if for example at DSD256 the per core graphs already hover constantly above 50%, DSD512 is not going to work with the same settings.

One can try to help these things with nVidia graphics card too… If things work fine with the -2s filter variants, adding suitable graphics card can help bring things to working level with rest of the filter settings. Depending on case GTX 1060, 1070 or 1080 may be suitable.