View Full Version : Performance degredation over time.

22-09-2017, 07:11
So far I've only experienced this at Knockhill (doing the community event w/ the Caterham)

Everything starts out smooth and fast but a few laps in the framerate starts dropping, and keeps going lower every few laps, even persists through pause and restarts. It's weird because the frame pacing gets all rubberbandy. But it always starts out fine for a lap or two after the track loads, pinned to my framerate cap of 75fps. I've tried dropping various settings to try and find a culprit, but none appeared to have any effect.

I'll have to try some other tracks tomorrow and see if anything similar happens, but 5 hours in so far this is the first time where it was obvious something wrong was happening mid-race. It was extremely noticeable in how much it was affecting my ability to drive the longer I was on that circuit doing laps.

oh yeah, specs: 4790k/RX480 8GB/16GB RAM

Morgan Henstridge
22-09-2017, 07:20
What are your system specs??

22-09-2017, 18:53
After some testing I think it might be certain weather settings causing this issue for me, or exacerbating it.

I capped the framerate to 72 in my AMD drivers (w/vsync off display is 75hz freesync) and gauged from there where it went.

That community event at Knockhill which I mentioned is using Overcast weather, and when I do that same track in the same car in the test drive mode with Clear settings, the performance stays at a constant 72fps. Switch to Overcast and while it starts out pinned to 72 for a lap or two, it then begins dipping lower and lower and the frame pacing gets worse the longer I drive. Every other setting was exactly the same in both instances, and I turned off weather progression just to keep things constant. I then tried different time of days (also without progression for consistency) to add more and longer shadows and such, but that did not alter performance in any way.

Then I tried a completely different track, Laguna Sega. Started out with Overcast (again no progression for weather or time) and after half lap of 72 it started dipping to high 60s, but still went back up to 72 in some sections. After a few laps by the time I was crossing the finish line it would be dipping in to the low 60s and topped out at about 68fps, all with the same awful rubberbanding frame pacing. I switch over to Clear weather and did 6 laps and it was locked to 72fps with one brief dip to 71 on the last turn of the second lap. Nearly perfect.

I haven't tested other weather types, there's too many of them. And frankly I'm already sick and tired of troubleshooting and beta testing this game at launch already, and I've spent so much time with testing these issues and more that I'm hours beyond the Steam refund range. but I can at least point to this one issue being easily replicable on my setup. Although I can't say for certain if this same degradation would eventually happen on Clear weather if I were to do enough laps / drive long enough, nor just how low the performance would degrade if I kept doing laps on Overcast. It's annoying enough to drive when the frame pacing is wonky and takes long enough to compare and contrast as it is without going full on endurance mode.

22-09-2017, 21:41
Another round of testing because this is really pissing me off, this time with AMD drivers capped to 74fps like most other games I play. Newest drivers, fresh install.

I loaded up Knockhill in the Caterham with no weather or time progression, drove around for a few laps then walked away from the game for 15 minutes, then came back and drove around again. This is without any other cars on the track, btw.

On Overcast: Started at a solid 74fps, quickly started dropping. When I was on the final straight on lap #2 it was ~70fps and I walked away. Checked back in a few minutes and noticed the framerate was around ~67 and fluctuating +3/-3 degrees and everywhere in between. I checked on it a few minutes later and it was doing the same thing, but was again lower overall. After 15 minutes I took out it around the track a few more times and the high was 66fps when the screen wasn't busy coming up the hill toward the finish line, and the low was 49FPS(!) - Far lower than I had ever seen it before when just doing ~5 laps at a time and quitting out when it started dropping and rubberbanding in the community event. This is extremely broken. Huge degradation over time, but I'm not sure why and I don't know who to contact about this. I'm sure if I let it go longer, it would keep going lower and lower.

On Light Clouds: Started at the solid 74fps cap and stayed there for the initial laps. When I parked it and walked away, it was pinned at 74fps. And when I came back 15 minutes later it was still 74fps. Did a few laps, still solid 74fps at the cap.

I'm not sure what the deal is. It makes no sense to me because there seems to a lot more going on visually when the sun is out with more visible shadows, the light rays and bloom, reflections, etc. Overcast is very flat and ugly looking by comparison, but somehow ruins my performance over time in this game. By an absurd amount.

23-09-2017, 20:00
Besides charting the performance degradation over time for myself in Overcast weather, I tried some rolling weather on various tracks. Clear > Clear > Overcast > Overcast, Overcastx2 to Rainx2, Clearx2 to Rainx2. Doubled up at 60x for both time and weather progression.

Framerate drops real fast when it switches from any weather type to Overcast and then FPS comes back up when Overcast goes away. Again this is baffling because Overcast seems to have a lot less going on visually, even Rain weather types with the wet road and reflections, rain drops and particles, plus the sun rays still peeking through the clouds does not affect performance like Overcast for me! I've only found one person on the internet willing to test some of this garbage themselves, and they seemed to come to a similar conclusion on their Nvidia card, so it's looking like at least the early performance hit in Overcast is not an AMD specific problem, although the long term progressive loss in performance still might be, no clue. https://www.reddit.com/r/pcars/comments/71uath/loss_in_performance_over_time_in_pcars2_wovercast/dne8256/

Another point that's worth mentioning is that even as it rolled past midnight with no sun and the dark skies, you could tell when it switched to Overcast because the framerate would drop just the same as in the daytime. And then when it went away and you could see the stars or as it started raining (depending on the weather setup), the framerate would immediately improve and stabilize. I know the obvious response here is to avoid Overcast settings until something can be done about (if they'll even look into and acknowledge this issue. I've seriously been talking to a wall and begging for QA with random people lately and no one else is talking about this stuff), but some community events force it (how I noticed this in the first place), and it rules out random weather and joining various lobbies because Overcast could happen at any moment.

And I'm sure people with the highest end rigs and performance to spare may not even notice this sort of thing, unless they were to do an endurance race in Overcast only and got hit with enough of the performance loss over time. Although some playing or testing with uncapped FPS and without vsync might be able to spot an immediate difference in Overcast vs other weather types.