I upgraded my Hive witness server last month. My previous server had the node server running and was using over 20GB of RAM, out of the 60GB available, it was a VPS, so it was a bit slow, although it had more than enough memory.
Now, my server is dedicated, it is a physical server, it has 128GB of DDR4 RAM, but is it is using, in total, under 20GB of RAM!
My sever has a Ryzen 9 5950x, so it is 32 threads, and it is barely using 5%, which is a bit wasteful, but makes me feel comfortable that I will probably not miss any blocks.
It is amazing, actually, that I still have over 100GB of RAM and basically all threads available, since the node is light.
I think there were updates to Hive that made it more lightweight to run.
If within 1 year I upgrade the server again I may even consider running a full history node, that maybe could use more of the resources. I will look into how to run a hive-engine server too, since there are plenty of resources for that too.
It is a very overkill server, but it is good, the last one made me miss almost 1 block per month, because it was a shared VPS, I would actually be surprised if this one, a dedicated server, misses one during the next whole year.