[Troubleshoot] Frame rates subpar / acting weird? check your monitor before wasting money on hardware upgrades

LjjlijJ · May 31, 2020

This is something I would like to share as I feel it might help some people with their PC gaming experience.

Simply put, an under-performing monitor could *seriously impact your frame rates/time.

(If you just want to see the important part of this post, scroll down to the bottom.)

Using my situation as an example:

My monitor is the LG 29UM68-P which features 2560 x 1080 ultrawide aspect ratios & resolution, freesync and 40-75Hz variable refresh rate.
Out of the box, you can select either 60Hz or 75Hz in Windows.
The rest of my PC specs are in my signature.

The gaming performance issues/behaviours I observed were:

1. Without any tinkering with driver / in game graphics / monitor settings apart from setting refresh rate to 75 Hz and turning on Freesync, frame rates fluctuated wildly.

2. Turning off all AMD lag/frame/sync enhancements, setting v-sync to always off and freesync to on, leaving monitor at 75hz, and using RTSS to limit frame rate to below the observed minimum in "1" did not result in consistent frame rates/time but caused the frame rates to dip further and fluctuate still although to a lesser extent. Upon closer inspection of the frame time graphs, the fluctuations seemed to be the result of consistent and periodic frame "hiccups". As can be seen in this video:

3. Regardless of any other settings, as long as the monitor is set to 75hz, 2D games suffered from extended periodic stutters.

4. Checked for frame skipping using https://www.testufo.com/frameskipping and confirmed the monitor was not skipping frames @ 75hz.

5. If setting the monitor to 60hz, all problem would go away.

6. I've tested using a better DP cable, reinstalling different versions of monitor drivers, tweaking using CRU as well as AMD custom resolutions - did not change a thing as long as I have the monitor at 75Hz.

As this point I was pretty confident the monitor was the culprit, specifically the "hiccups" seem to relate to display timings because when I use custom resolutions to set refresh rate at 74Hz & timing standard to GTF, the hiccups were almost eliminated; but if I change timing standard to anything else while leaving refresh rate at 74Hz, the hiccups would become prominent again (though not as bad as when at 75Hz).

Eventually I worked out a solution with a small caveat: simply use custom resolutions to set the refresh rate at 73Hz. After this my frames behaved the same as if the monitor is set to 60Hz, being that:

Frame rates no longer fluctuated wildly and both min and max frame rates improved (pleasant surprise!)
Using RTSS to limit frame rate resulted in perfectly flat frame time graph (there could still be occasional "poles" but those absolutely could not be noticed during gameplay).
AMD Enhanced Sync seemed to work properly in that the frame rates could be well above 73 and yet there would be zero stutter, zero hiccups, zero tearing and zero lag (as far as I could tell). Previously @ 75Hz, Enhanced Sync would cause some weird frame behavious which was hard to pin down and describe.
2D games now run 100% smoothly, as they should.
No other settings seemed to cause any above-described issues at all.

So, at the expense of 2hz refresh rate, I'm now having perfect gaming experience (with FreeSync!). Not too shabby!

(Too bad I've owned this monitor for longer than the warranty period. If not I'd return it and get a different one...)

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Summary/Conclusion/Important part

If your frame rates/time are below what you would expect, particularly if you experienced stutters in 2D games, do these before you declare your CPU/GPU/RAM incompetent:

Set up in game OSD using RTSS to monitor frame time behavious.

Use RTSS to limit your frame rate to just below the observed minimum. If you observed consistent, periodic frame time spike/hiccups on a flat base line, your frame problem was most likely caused by your monitor.

If your monitor is still under warranty, try returning it and get a different one. Otherwise, use custom resolutions function to set your monitor at a lower than rated refresh rate with whichever timing standard that would give you flat frame time.

Unlimit your frame rate in RTSS if you want, and set your driver settings to your usual preferences.

Enjoy!