I have the following observations from WiredTiger stack that i investigated:

1) WT use calloc for heap operations, malloc should be cheaper to use.

2) I also suggest using Low fragmentation heap (http://msdn.microsoft.com/en-us/library/windows/desktop/aa366750%28v=vs.85%29.aspx), we have something like LFH implemented in MMAP

1) i opened this as FYI, in case we have to improve this now
2) Please assign this to me and i will create the workload that measured the impact post 2.8

Eitan