Can you take a look at this page and see if any of these conflicts apply to your computer? This a list of software that is known to cause issues with the editor and a few seem to match your description.
I have been having this issue for a while. Thanks to this post, it has been resolved. i thought it was my RAM but it was the GPU Driver: EVGA Precision X driver. The only downside is that if i close the Driver it makes the GPU really hot and the GPU fans doesnt start until temperature goes above 60 degrees. i hope there will be an update or patch to fix this on the new versions of ue4 (4.11) so it can be compatible with the driver and cool my GPU.
While I’ve not tested this myself and am not 100% sure if it’ll work correctly, I would suggest trying MSI Afterburner as another option for setting up the fan profiles for your GPU. We haven’t had any reports that I know of with MSI Afterburner having any compatibility issues. Please let me know if it works correctly for you, as I’d like to know if I can suggest it in the future.