What I noticed on my machine is that I must use paired cores.
For instance, I had isolated 6-14 and 7-15, which were the logical threads shown on the dashboard. I assigned 6 to the emulato rpin and the other 3 to the Windows 7 VM. Doing this basically gives me very low latency of around 100-150 and hardly ever spikes above that.
I just tried changing this so that only 7,14 and 15 were isolated. With 14 used as the emulator pin and 7-15 assigned to the VM, I jget massive latency spikes that basically make it unusable.