I'm experiencing erratic behavior with WP 12's hypervisor performance, when 3d acceleration is active.
On my first attempt, the 3d acceleration was very impressive (around 60% of native GPU performance, when testing with 3dmark).
However, when I've attempted to test a game, WP behaved erratically.
What happens is that, while the 3d acceleration is performant, at times the WP hangs. When this happens, the guest stutters for long intervals (2-10) seconds, without an obvious cause; the GPU load on the host drops to zero, while the CPU load (on the host) skyrockets.
After the first stuttering episode, the system will keep stuttering more or less frequently, even outside the context of 3d acceleration (e.g. opening other guest programs).
The issue is very strange. It seems that it's mitigated by increasing the amount of virtualized processor, which is something that doesn't make much sense.
My hypothesis is that there is some data structure that gets overloaded, and it's never properly cleaned, for example, an allocator. The mitigation above could be explained if the data structure is split across the virtualized processor. The high CPU load can be explained by the hypervisor performing cleanup tasks. The 3d load itself (in terms of processing power) doesn't seem to be the cause, as there is not visible lag/screen corruption before the performance starts to crumble.
Is this a know issue? What puzzles me is that this is erratic. Even ignoring the game, 3dmark runs very smooth sometimes, but not on others, even if the conditions are as reproducible as it gets (being a standard benchmark).