let me address each of these:
- Disable Hyper-Threading (Intel)/Simultaneous Multi-Threading (AMD) in the UEFI BIOS if your CPU supports it and if your BIOS allows you to modify this setting.
This one is not explained and makes zero sense. This, if anything, helps the performance of your CPU, not hurts it. I strongly disagree with this advice.
- Disable advanced power-saving and dynamic performance options for your CPU if applicable. This usually needs to be done in the UEFI BIOS of your computer and includes ‘Enhanced Intel SpeedStep (EIST)’, ‘AMD Cool ‘n’ Quiet’, ‘Intel Turbo Boost’, and ‘AMD Turbo CORE’.
Most of the power saving options only apply when you are idle, so they wouldn’t really kick in if your computer is doing anything. The “turbo” functions make your CPU faster. If you are doing intense DSP or your computer is lagging behind, this could help prevent dropouts. It will come with the penalty of heat, an increased power bill, and possibly higher electrical noise (which may impact sound quality if your equipment is not shielded properly).
- Disable C-States in the UEFI BIOS if this is accessible. C-States allow your CPU to sleep when idle, which may interfere with real-time applications such as audio. This option is often called ‘Disable CPU Idle State for Power Saving’.
C-States just turn off parts of the computer when idling. If you need it, they will come back on. If you are using your CPU for real-time applications, turning this off will not make an impact, as your CPU is going to be used, not idling.
I may be reading the wrong thing, but it says nothing about hyper threading in that document.
The general consensus here is that hyperthreading improves performance but can increase latency in a few cases. In realtime cases this may matter a bit (for example, how quickly your ear hears sound when you pluck the strings on a guitar). Remember, we are talking nanoseconds to microsecond ranges and sound travels at about 1ft per millisecond – so improving latency by something as absurdly large as 1000 microseconds, would be equivalent of stepping away from the speaker by 1 ft.
Anyway, this has nothing to do with sound quality. One exception is when you are have latency inconsistencies that screwing up your processing of audio in the DAC. Buffers and a good clock should prevent both. You’d have to have some pretty bad gear to have these issues, and the result would be pops and clicks, not fidelity loss.