VR: 90 FPS constant as soon as mouse is moved

Vranq · Oct 18, 2021

I just made a strange discovery: In rF2, I average around 70 FPS (WMR @ 200% SS) on the track when I turn off motion smoothing. The GPU frame times "bounce" up and down at regular intervals in a range between about 5 and 12ms.

As soon as I start moving the mouse, which is not even visible on the track, I get a constant frame rate of 90 FPS and the GPU frame times stay just as constant at a low level of about 5ms. This only lasts as long as the mouse is being moved. As soon as it stands still, the FPS goes down again and the frame times bounce up and down again regularly.

Does anyone have an explanation for this phenomenon and how I might be able to get the 90 FPS consistently without a hand on the mouse?

(My PC: AMD Ryzen 7 5800X, ARCTIC Liquid Freezer II 280 , MSI X570-A PRO AMD X570,16GB G.Skill RipJaws V DDR4-3600 DIMM CL16, Powercolor RX 6900XT, Bitfenix Whisper Series 850 W, Windows 10 Pro)

Vranq · Oct 19, 2021

I made a small video (sorry for lousy quality). This is before going on the racetrack. On the racetrack there are only GPU frametime spikes and CPU frametime stays at a low level (4-5ms).

As if it isn't already crazy enough, I've just discovered that X-Box controller stick-movements and pressing keys on my keyboard also produce the same effect. It even goes so far that I can create a workaround for constant 90 FPS by programming a macro on my Logitech G11 keyboard that constantly "spams" the same letter and the result: constant 90 FPS.

I just found out it isn't a VR issue. It happens without VR also but only in rF2. When using a monitor at 3840x2160 the FPS are constantly at 75 FPS and with mouse movement exactly at 140 FPS.

Same numbers at FullHD resolution too...

PedroF69 · Nov 5, 2021

Something strange is happening with your setup, i race with vr only, and don´t have that magic FPS trick, i tried it and is the same. Anyway if that was a bug in Rfactor2, your post would had many replies.