Are you using virtualized performance counters?
No.
The dominant exits are page faults (0x4e), as expected. They are only about 50 times as frequent as CR accesses (0x1c) [likely to be CR3 changes]. If you are spawning about 4250 new processes per second, and they have a working set of about 200K, that would account for these VM-exits.
Actually, the whole test suite run, which takes 100 seconds on the Windows 8.1 64 bits VM, spawns ~2000 processes. This makes 20 processes per second, on average, shared among the 4 processors. On other tasks, such as building C++ projects, which run multiple, but long-lived processes, the performance is not so bad. So it seems that process spawning is the key factor here, as if it were extraordinarily expensive. Another example: a Git frontend invokes the git executable about 40 times sequentially to show the detailed status of a source tree: it takes 12 seconds on the Windows 8.1 machine with 4 cores, 6 seconds with one core. An Atom N270 netbook takes less than 2 seconds, the Windows XP guest is slightly slower.
Out of curiosity, what virtual hardware version is this VM? If it isn't virtual hardware version 11 (compatible with Workstation 11), I would suggest upgrading it
The slow Windows 8.1 64bits guest is using version 11, the same as the "fast" Lubuntu 64 bits guest. The "fast" Windows XP 32 bits guest is using version 7. Anyways, I'm experiencing this problem since I installed VM Workstation on this machine, circa 2009. At that time, after much experimentation, I came with a config for the Windows XP guest that made it acceptable, on performance terms (it mostly related to using Binary Translation). Linux guests, 32 and 64 bits, performed well without special tweaks. But so far I was unable to make the Windows post-XP to perform acceptably. Now it is a serious problem, because the XP VM should be deprecated and replaced by something more modern, but there is no way this can be achieved with VMs that perform like a 5 year old single-core netbook.