Extreme FPS drop when moving in the biomes with lots of leaves

can confirm, i get a lot of fps drop in jungles

Does setting "Graphics" to "Fast" help? If this issue is truly caused by the amout of leaves, that should eliminate it.

Very strange, after switching to fast and back I don't see the issue anymore

Now I only see some spikes on place/break block

I have experienced this too in 1.14.2. It's especially noticeable on my custom map (vanilla, of course). The map has very dense rain forests, and if I break or place blocks, I get unbearable amounts of lag. When I break a tree trunk so that its leaves start to decay, the FPS graph's spikes on the debug screen go all the way up to the top of the window.

Interestingly, if the block being broken is tall grass, the lag is much less extreme. For this reason I believe that lighting updates are the primary cause of problems here (since tall grass lets light through), and leaf blocks in the jungle amplify the effect.

Edit: If lighting updates really are to blame, maybe they could also explain why fire causes lag. 

I noticed severe lag while playing on a friend's realm when he was chopping down a tree in a plains biome. The effect was similar but not as extreme, and I am fairly sure that the cause is the same as here. So perhaps this bug report could be renamed or merged with another similar one. Do you agree?

Edit: what I previously mentioned about blocks being broken in jungles causing lag is no longer an issue in 1.14.4. Moving around still causes severe lag, so the issue is probably with leaf block updates. 

Please check if that's still an issue for you in 19w45a.

Conirmed for 1.15.1

Can confirm this as well in 1.15.2

I originally tested this with OptiFine installed (HD_U_G1_pre10). Also tested in vanilla with the same results.

I have translucent blocks set to fast to reduce lag, but my frames still drop to 10-20 where I regularly get 200-400 frames (vsync off, unlimited frames)

Can confirm for 1.16 pre release 5

Confirmed in 1.16 Release Candidate 1.

Can confirm for 1.16.1

still happens in 20w27a

In 20w30a

It has no lag to me, but I think it's relative to the power of the computer and the size of the jungle.

True, Lag can be solved in many cases with more power

not everyone has money or the possibility to have the latest and the greatest

For me this issue is solved because the fixes where just enough to run smooth on my machine

but in the days of 1.14 it was very bad on my machine and solved around 1.15.2

In that period I avoided playing in this biome

I can imagine that this is not the case for everyone

performance is very difficult to analyse if it is not obviously wrong

tuning is the key for every element in the code, but I don't have the source-code and time to check
(I spend my free time on playing the game 🙂 )

Some people experiencing this problem seem to use 3d vines ressource pack from the vanilla tweaks. (example MC-200158) Seems like 3d vines actually have big impact on the FPS. If you are using that, I would recomment to not use that, if you have massive FPS problems in the jungle. That would probably drastically increase your FPS in the jungle.

Yeah, 3D vines crashed my computer twice when I entered a jungle biome, but another part of it is leaves rendering. If that's a problem, try switching to fast graphics. This isn't a sure fire fix because leaves also are random ticked constantly even on fast graphics which causes lag as well.

If it occurs in swamp biomes as well, it's probably vines. If not, it's probably leaves.

Can confirm in 1.17.1 Pre-release 2.

Can confirm in 1.17.1 Release Candidate 1.

Can confirm in 21w40a

Can confirm in 21w44a.

I am having major issues with this. I made a world in 1.17, transferred it to 1.18 after the update and I had progressed far in the game. I entered a jungle biome and the fps dropped so low and then completely froze the game. I couldn't exit the world, couldn't close the game or open task manager to close it so my only option was to force shut down my computer which has now corrupted my entire game and I have lost all progress. This isn't the first time I have had this happen when entering a jungle biome

Affect 1.19

Can confirm in 1.19, 1.19.1 and 1.19.2.

I can confirm in 1.19.2

Can confirm in 23w05a and 1.19.3

Can confirm in 23w07a

Useful information in MC-252047 relating to this bug.

I want to point out that vines are also a significant factor that contribute to the frame rate drop in these type of biomes, not only leaves (especially 3D vines which i'm not sure if they're even supported at this point). Mangrove roots also have this issue and are even worse than leaves which i think they're tracked in MC-250246.