I've been having one hell of a time with trying Server 2012 R2 in my environment. The latest is trying to migrate from a physical Server 2008 R2 machine w/ SQL Server 2008 R2 to an ESXI VM running Server 2012 R2 and SQL 2014. The performance is terrible by comparison. In our application that runs on top of this SQL database, users are experiencing delays of 5-30 seconds on functions that previously had no delay.
The hardware behind the VMs is fine and more than enough (brand new setup). VMs use VMXNET3 for NICs and paravirtual for the data drives (best practice settings from what I've read). I truly to not believe it's anything hardware related.
Anyhow, I've had 2 DBAs look at the VM and SQL and both say it's fine, not even breaking a sweat, wait times are next to nothing... etc. I've checked performance at the VM, the host level, and...