Check your settings in the advanced tab.
Tick [x] Multicore DSP. Try with both Cuda offload fully ticked (like on my picture) and unticked. Both are tri-state checkboxes. Ticked is like on my picture.
HQPlayer users usually use higher performance graphic cards. If the GPU is slower than the algoirithms running on CPU expect, CPU then needs to wait for GPU. Therefore I suggested to try two different CUDA offload settings.
For CUDA offload really to work you need to have the latest nVidia drivers installed for your card. If CUDA offload works, after starting playback you see for few seconds on HQPlayer Desktop status line (bottom line) such a message:
Important is the 1st part resampler=enabled.
Then, set DSP pipelines to 8 (like on my picture) to lower RAM usage.
If that wouldn't help, maybe your CPU clock is not enough high. What is your CPU exact model? i7 doesn't tell much since many i7 generations exist.
I'm assuming you are running Windows. Check what is your current power plan.
To keep CPU clock high you need either High Performance or Ultimate Performance Power plan.
How to enable it if you don't see it in Control Panel:
https://www.google.com/search?q=win11+set+ultimate+performance+power+plan
If power plan setting still doesn't help, you may yet try to experiment with Blocks per cycle value (the 1st picture).
Sometimes stuttering comes out of USB issues. I'm assuming you are using USB interface to connect Holo Red to your DAC. Use only USB2 or USB3 certified USB cables.
Last thing: I'm not sure if stock Holo Red firmware works at 1.4/1.5M rate. Other Holo Red users could confirm it. Jussi prepared an alternate OS image for Holo Red. You may write it to an other SD card with
Rufus and try to boot your Holo Red with it (don't overwrite your original SD card).
Download naa-500-raspberrypi4-holored.7z from
https://www.signalyst.eu/bins/naa/images/, unzip it and use Rufus to burn it to SD card.