Nvidia SLI lag in Windows 10 build 1607 VM

Question

On a fresh Windows 10 Enterprise (Build 1607) install in a ESXi 6.0 U2 VM, when SLI is enabled on a pair of GTX 980s, the cursor and UI effects will display significant lag when present on a display connected to the GTX 980 when using drivers 372.70, 372.90 and 373.06. The cursor will not lag on the VMware SVGA display with the VMware SVGA driver disabled to prevent the remote console from displaying its own cursor, or with SLI disabled. This does not occur either on a Windows 10 (Build 1511) VM using the 372.70 driver. Does anyone know what changed between Windows builds which could be causing this, and if it can be disabled?

The drivers were activated by adding hypervisor.cpuid.v0 = false to the VMX file of the VM. The VM has 100% of the CPU and memory reserved, and latency sensitivity was set to high. SLI was activated with DifferentSLI Auto 1.5. I could not try this with the 375.63 driver as DifferentSLI does not support this driver yet.

Answer 1

Strangely enough the root cause of this issue had to do with the order of the PCIe devices in the VMX file. I'm not sure how exactly this would affect anything, but it clearly does after repeated testing.

In the "SLI Lags" picture below, this was the default order of the devices in the drop down menu. In the "SLI Works" picture it was the order in which I had it working in my 1511 build VM.

After removing and re-adding all the PCIe pass-through devices of the 1607 build VM to match the order of the 1511 build VM, SLI no longer lags! I also noticed that in the "laggy" 1607 build VM, in the Nvidia Control Panel my monitor would show to be connected to GPU #1, whereas in the "working" VM (and in a bare metal Windows install) it would show to be connected to GPU #2. This in itself is strange as the GPU which the monitor is connected to is on the PCIe bus of CPU #1, and the GPU without a monitor connected to is on the PCIe bus of CPU #2.

In case anyone is curious, the CPUs are Intel Xeon E5-2660 v2 on a Supermicro X9DAE.

SLI Works

SLI Lags

In case Ramhound was wondering about case sensitivity or anything similar, in all instances the PCIe pass-through devices were added through vCenter.