ok, after struggle with it for another hour, i got it resolved. Here is my finding:
1 i have to uninstall both SLR and deoVR completely, not only through uninstaller but also delete app data/locallow files, as well as all registery files under Hkey_curent_user\software
- reinstall SLR through installer and update
Now the SLR will work perfectly with low GPU usage in the menu, if I install DeoVR player from steam on top of it, immediately everything fucked up, meaning the version of Deovr in steam is buggy with high GPU usage even in menu without playing any video, but the package packed in SLR is fine (may be newer or older).
Lesson is: never install deovr player from steam, if you did, have to remove all the traces including appdata/localow as well as reigistry before reinstall. And SLR dev please do NOT use the version of deovr (said as 6.4 in steam update news) in the steam to include in your next update