this happens with all mods disabled.
my setup, not sure how much is relevant but here it is:
graphics: radeon rx 580 graphics card, driver version 19.8.2 (adrenalin series drivers)
windows 10 pro
cpu: amd ryzen 5 2600 (6 core, 12 thread, 3.4ghz base)
ram: corsair vengeance led 16gb (2x8GB) 2400mhz ddr4
multiple displays connected. one at 4k 60hz, the other at 1080p 60hz.
given:
all mods disabled
factorio 0.17.68 installed and running
steps to reproduce:
1. start new game, vanilla settings
2. open debug mode and enable the fps/ups viewer and other relevant stats
3. move around in-game (fps and ups should stay at 60)
4. run `/c game.speed=2` twice (once to trigger the achievement warning, and another time to actually set the game speed to 2)
5. move around in-game.
expected: fps stabilizes at 60 or below, while ups stabilizes at 120 or below.
actual: fps "jumps" up to 120, and ups jumps to 120. in addition, when moving around, the actual fps seems to drop and there's massive frame skips and jumps.
note: strangely, when unfocusing from the game (clicking somewhere else, alt tabbing) the fps stabilizes back to 60 and the ups to 120. in this situation i can even set the game speed to 100 and with the game unfocused the fps will settle at 60 and the ups at 6000. but once i focus on the game (click anywhere on it), the fps jumps to 110 and the hitches start, and the ups drops to about 3000.
note: this didn't seem to happen a few versions back, like back in 0.17.5x or 4x. i'll test some more and update when i know exactly which version this started on.
another note: i'll try to record some video of this behavior with obs's record function. i may post a link to it here once i obtain that.
log file: https://pastebin.com/1xZuL5PE
screenshot with good performance (60/60): https://snipboard.io/bY9BlT.jpg
screenshot with strange/bad performance (106.3/120): https://snipboard.io/CKgRiM.jpg
edit: tested while recording with OBS, and there were no performance issues at all. i could not get it to happen again while recording. even with OBS just open, the performance drop didn't happen. but the moment i closed obs, then factorio started hitching.
edit+update: ok so i just updated my graphics driver to 19.9.1 and did some windows updates and i can't seem to reproduce the issue. not sure if it was because i rebooted or because i installed the updates.
for now.... i guess disregard this bug? until i update it again.
