In-game FPS tanks compared to Studio testing session

Bug Reports Engine Bugs
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#1

Our game features a large map, but it’s optimized for performance. I’ve always been able to run it on 120 FPS on my system, and it runs pretty smooth.

Recently however, I noticed a significant drop in my in-game FPS. It feels like I’m playing on less than 60 FPS, even though I made sure 120 was selected. Testing in Studio does appear to be much smoother compared to playing in a live server, although not perfect and on the contrary my game has always run better in live servers.

I don’t recall making any massive changes to client code. But to confirm, I disabled practically every client-sided system to verify those were not the source of the massive FPS decline. This made no difference.

I checked all my script activity and other logs, and everything to my discretion seems normal.

I noticed the microprofiler had some definite CPU timing spikes, the latency on average went up to about ~17 or so.

Another interesting thing to note is that the game did seem to run a tad bit better once I went in the basement, which this would seem to point to an engine flaw from a recent update possibly.

The average frame times I would see from the microprofiler in Studio sessions is around 9-15. In live servers that number grew quite a bit, it became around 11 min to 20 max.

I tracked down the culprit using the microprofiler, and I certainly found at least the primary cause. The code below is executed client-sided once for every camera object that exists, and is intended to rotate the camera back and forth. This gave me no performance issues in the past, but now apparently it causes my FPS to tank significantly. I added a timer to restrain how frequently the camera update logic gets called, but apparently that makes no difference now? If you guys knew of any specific internal changes that could impact this logic or had any other feedback I’d greatly appreciate it. Additionally, its script activity is normal despite there being many cameras all being updated.

Could this have something to do with the new physics stepping/sleep improvements update that rolled out recently? The camera objects are unanchored, being welded to the root part which is being rotated with this code.

RobloxStudioBeta_AXZtqMkBce
RobloxStudioBeta_AXZtqMkBce771×695 36.8 KB

Additionally, my specs are as follows:

RTX 2080 Ti
32GB RAM
Intel i9-9900k

Thanks so much for your time and insight. :slight_smile:

Expected behavior

I expect the game to be running smoother on my system, which is older but it still can run new games on good quality settings.

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#3

@C_Sharper Thanks for reporting this issue.
To help us investigate the issue more effectively, please provide the following details:

  • A link to the place where you observed the issue (if it’s public)
  • When the issue first started occurring
  • Whether your experience uses Streaming
  • A simple repro file that demonstrates the issue — this will help us triage and address it more quickly
  • The device you’re experiencing the issue on (Desktop, Mobile, or Console)
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#4

Thanks for your response.

Here’s some further information:

The public game can be played at: Forbidden Hunt - Roblox

I believe I initially noticed the FPS loss more recently, I want to say maybe two weeks or so ago, probably around that time frame.

My game does not use streaming.

I use desktop.

Additionally, I will send you a repro file privately.

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#5

@C_Sharper Thanks for the information. We will ask the owner team to reach out to assist with this.

1 Like