A rainbow beacon is a beacon with stained glass pane placed directly above it, creating a multicolored beam that changes color as it rises through the sky. A rainbow beacon is more laggy in 1.21.5 compared to 1.21.4.
Test: a rainbow beacon in a default superflat world. The Beacon with stained glass panes above from y=-60 to y=320, with repeating pattern: red, orange, yellow, lime, light blue, blue, purple, magenta, pink.
1.21.5 with no beacon: 281 fps
1.21.4 with activated beacon: 80 fps
1.21.5 with activated beacon: 10 fps
See attached screenshots.
Environment
From 1.21.5 when beacon is activated F3 debug screenshot:
Java: 21.0.3
Mem: 22% 457/2048MB
Allocation rate: 042MB/s
Allocated: 43% 896MB
CPU: 10x Apple M1 Fro
Display: 3456x2160 (Apple)
Apple M1 Pro
OpenGL 4.1 Metal - 89.3
Attachments
Comments 7
To amend my previous response, I think this is a performance issue with 1.21.5 which is not isolated to the beacon. Having done a bit of research it seems that others are having frame rate issues with 1.21.5. I did a bit of testing myself facing down in a superflat world and I did find that I am getting significantly fewer frames in 1.21.5 than in 1.21.4, despite it being the same world.
[media][media]
Hi there!
I'm currently reviewing older, unconfirmed reports to help keep the bug tracker up to date. I’ll temporarily resolve this as Awaiting Response for now.
Please let me know if this issue is still happening for you in Minecraft 1.21.6. If you reply, the ticket will automatically reopen and I’ll be happy to take another look.
Hi turbo,
I experiemented with the same set up in 1.21.6 and got similar, but better results: 56 fps when beacon is deactivated and 18 fps when beacon is activated (see screenshots below).
[media][media]There is a noticeable improvement from the 10 fps in 1.21.5 to 18 fps in 1.21.6. But a three-fold fps drop in 1.21.6 is still not desireable compared to the neglagible fps drop in 1.21.4: 56 fps when beacon is not activated and 58 fps when beacon is activated (see screenshot below).
[media][media]I did more experiments in the 1.21.5 snapshots and the problem seems to arise from 25w09a or 25w09b (I did not test on 25w09a as the menu did not show text). I recorded 58 fps in 25w08a and 9 fps in 25w09b.
The snapshot 25w09a may be the culprit as there are bug fixes involving beacons (Minecraft Snapshot 25w09a).
We do not have enough information to find the cause of this issue.
While the lag occurs, please press F3 + L once, then wait a short moment until profiling has finished.
Afterwards, please attach the generated .zip file containing the profiling results here. The file path is shown in chat; the file can be found in minecraft/debug/profiling/<DATE>.zip.
If you are playing on a server please additionally run the command /perf start to create a profiling report for the server. In case you do not have the permission to run this command, make sure that you're a server operator.
Once profiling has finished, please attach the generated .zip file from debug/profiling/<DATE>.zip of the server folder.
This issue is being temporarily resolved as Awaiting Response. Once the requested information has been delivered, the report will be reopened automatically.
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Is this the lag problem I’m having since upgrading to 1.21.5? Needs fixing ASAP.