Operating system: Win7 Home Premium 64-bit, SP1
Graphics card: Nvidia GeForce GTX 750
Broken: 2.80, c97c76c01c1d, blender2.8, 2019-01-04
Worked: 2.79, 5bd8ac9, blender2.79, 2017-09-11
In both versions, CUDA is activated and GPU is used.
The lagging is seen both with Cycles and Eevee render engines.
Short description of error
As seen in the videos, creating a cylinder, applying a subdiv modifier, applying a loop cut & slide and moving it up and down:
Blender 2.79 --> smooth and fast display
Blender 2.80 --> laggy display
Exact steps for others to reproduce the error