Threadripper Memory Speeds

[Jerky_san]

I was wondering what you guys get in a windows 10 VM for memory speeds? Is it close to your baremetal speed? The L3 latency is extremely high and I have no idea why. The Memory latency has a lot of overhead and technically the l1 does as well. I finally fixed a lot of my stuttering by not passing my USB controller.

VM

Bare Metal

Edited November 10, 2018 by Jerky_san

[bastl]

I did a couple tests with my 1950x in the past. I tested all the different memory configurations in the BIOS with different core assignments. The cache latency never where close to the bare metal results. The bandwith depends on which cores you give to the VM and how your memory is setup. 

 

In this thread you find a couple test results and conclusions. Don't get confused on my first postings about wrong core pairings. I first thought unraid shows me the wrong core pairings.

 

I still have have the issue no matter how i set up the BIOS or configure the VM, especially the RAM assignment, it looks like the VM always uses a small portion of RAM which is connected to the other die which i don't pass cores from to a VM. 

[Jerky_san]

13 hours ago, bastl said:

I did a couple tests with my 1950x in the past. I tested all the different memory configurations in the BIOS with different core assignments. The cache latency never where close to the bare metal results. The bandwith depends on which cores you give to the VM and how your memory is setup. 

 

In this thread you find a couple test results and conclusions. Don't get confused on my first postings about wrong core pairings. I first thought unraid shows me the wrong core pairings.

 

I still have have the issue no matter how i set up the BIOS or configure the VM, especially the RAM assignment, it looks like the VM always uses a small portion of RAM which is connected to the other die which i don't pass cores from to a VM. 

Thanks for pointing this to me. I have both sets of cores that have memory controllers assigned to the VMs. I put a buffer VM to take up enough ram to force it to use nearly the proper amount of ram from both sides but still has horrendous transfer speed and latency. The L3 is the most concerning and almost seems like a bug in QEMU/virtio or something.