Definitely far from the fastest things around, but could be a fun cluster project.
$79.99 + shipping, best offer
Roon endpoints!
They are fun lil boxes, makes for a good lil lab setup for small docker swarm 
Remember, These are not the T620p. No PCIe slot here and displayport 1.2 which means 4k30 max.
Full specs here. – HP t620 Flexible Thin Client Product Specifications | HP® Customer Support
I switched out my Pi for a T520 for Home Assistant. The T620 would do the same. On one hand, it’s nice to have greater expansion possibilities (ie not just run HA, could run a few other low resource services). On the other hand, if you don’t know Linux/Docker, you spend a lot more time than the plug and play of HA-Pi
