Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.20
Broken: version: 2.82 (sub 6), branch: master, commit date: 2020-01-19 22:44, hash: rB81b7f8efaf7a
Short description of error
I tested with same settings and I have the same time for whole frame and region.
It makes problem, when I want to render small part zoomed. Now the workaround — is making new camera with smaller angle and render from it.
If it is limitation, may be render should create temporary camera that cuts region.
Exact steps for others to reproduce the error
Render same scene with Eevee through F12 and it`s region and compare render time.