Enough so that It was much easier to hear the affect of different types of feet under my preamp, server and DAC. I say all this as I just put the ADD-Power devices in my power distribution strip. The layout of components to reduce Electro/magnetic interference.
The actual case and its ability to damp vibrations. Process power has an affect, but your not taking into account how the PS are isolated, damped and implemented.
ROON HQPLAYER SOFTWARE
If you want good sound, it's not just software speed or lack of process power. This filter seems to have a more stable image then the xtr's, also the xtr has more "sparkle" then I prefer. One other follow up, after doing quite a bit comparison I prefer the poly-sinc-short-mp-2s filters over the xtr version. As with most setup in audio, it pretty much stays the same after you get it set to your preference, or so it seems to me. but it seems to be rather funky software sometimes, in my view. HQPlayer is the best performance playback engine, by a little.
I watched CPU usage and it appeared to be similar results as before but with the more demanding xtr filters, but using the 2s version. The 2s filters play them just fine including the more demanding xtr filters. Using the non-2s filters I found my version was not able to play PCM files with 44.1 base clock i.e. I just discovered a very strange issue with HQPlayer filters. So anyway, that is the results of some pretty extensive testing and what appears to affect smoothness of playback with Roon/HQPlayer the most. I have been hesitant to try the xtr versions of the filters since I was reading a thread where Jussi was saying that the xtr filters are 5 times as long and drove his 10 core machine to 90% usage. Previously, on my last quad-core i7 machine with a Nvidia GTX-980 I was not able to play the non-2s versions of the filters without stuttering. In HQPlayer I am using the poly-sinc-short-mp filters. So by far the biggest drain on the system is CPU usage. This definitely leads me to recommend the more cores the better as far as CPU choice. I have also seen that the CPU load is distributed across all 8 cores. I am finding that up-sampling DSD files are using between 33%-43% of the CPU cycles. I am finding that when up-sampling PCM files the CPU usage is between 25%-30%.
ROON HQPLAYER FULL
However, what I am finding, non-stop full loads never use more than 25% of the memory. I was considering adding another two sticks of memory to get it up to 32 GB. What I am finding is that the disks are using nothing, under 1% at all times. With monitoring I can see the HQPlayer uses a good chunk of CPU cycles compared to everything else, combined. What I am finding, in my system is that the Roon/HQPlayer combo is more CPU intensive then anything else. Oh, I am up-sampling everything to DSD512/48, 24.6 Mhz. I have been experimenting and monitoring a bit. I can always add one, but I prefer not having the power needs and fan noise of a top end Nvidia card, for now. I choose to leave out a video card for CUDA Core off load for now. The CPU is a brand new i7 8-core monster. Liquid cooled with slow spinning air intake fans that only spin up when needed (in other words almost never).
Of course it is gold power supply with heat sinks on the M.2 drives and on the memory chips. CD Rips and Flac downloads are on the two 2.5" SSDs. The operating system, software installs and my SACD rips run on one M.2 and the DSD downloads, which are by far the largest files are used from the second and fastest M.2. It now has 4 drives, 2x 1 TB M.2 and 2x 500 GB 2.5" SSD drives. I also would love to hear your results with different filters, etc. Hopefully this might help someone decide what kind of machine they should put together. I wanted to see what level machine and what results people have been obtaining. We all have our opinions so we will leave it at that for this discussion please. I do not want to turn this into a pre-built music server/streamer versus purpose built computer as a dedicated music server discussion. I was curious what computer specs people are finding work well with Roon and HQPlayer.