Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: Intel(R) Iris(R) Plus Graphics 640 Intel 4.5.0 - Build 220.127.116.1154
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-03-05 06:10, hash: rBb5d154f400e4
Worked: version 2.92 (a build from mid January)
Short description of error
After using Blender for a few minutes, the viewport gets very laggy. Just trying to move a small cube, results in a delay of ~1 second for the object to catch up to the mouse if I quickly try to move it from one side of the viewport to the other. This seems to happen when I have both 3D objects and Grease pencil strokes. Possibly also connected, undoing grease pencil is very slow.
Exact steps for others to reproduce the error
Both of these files were started from scratch with the 2D animation preset. I drew a little, made some shapes, Alt-D duplicated them. Everything worked perfectly, the viewport responded quickly, and undo worked with no noticeable delay. Then I continued to draw and duplicate, and at some point, everything grew sluggish (And continued that way). Moving an object resulted in a long lag, and undoing a grease pencil stroke resulted in a long lag. If I save the file, then re-open it, the lag continues. But if I close out Blender completely, then when I restart, the file behaves normally again. So it is something that is "building up" to eventually cause the lag, but closing blender clears it out and when it starts everything is fine again. This was not an issue with the mid-January build of 2.92 I had been using before installing the release 2.92 or the current 2.93 build.
I haven't been able to duplicate this on a faster computer with a graphics card, but it is very noticeable on this computer. Again, everything works perfectly once Blender is closed and re-opened, but then several minutes into working, the lag returns and becomes very difficult, causing me to have to restart the program many times in a session to continue working.
Thanks! Sorry I don't know exactly what is causing it.