By testing my SSW in the 1.14 I noticed that my gold farm (Design from https://youtu.be/l9oteFEj770) caused more lag than in the previous version 1.13.2

I gathered a standalone copy of the farm and debugged it.

How to reproduce:

Do the following steps for each version 1.13.2 and 1.14

1. Download the attached world and paste it into your saves
2. Optimize and join the world
3. Get yourself some snowballs
4. Fly to the upper edge of the glass box in the center and land there
5. Update your gamemode to survival
6. Start debugging with: debug start
7. Now activate the farm (Video example: https://youtu.be/bIOKkBAnAKU?t=40)
   • Throw a snowball against a zombie pigman
   • Jump fast down onto the highest trapdoor
8. Wait a minute while the pigman are running towards you, then die and respawn
9. Stop debugging: debug stop

Results (see attached files)

1.13.2
[06] | | | | | | minecraft:iron_golem - 8.09%/7.14%

1.14
[07] | | | | | | | minecraft:iron_golem - 31.82%/11.52%

In 1.14 the debug root value changed from
[00] levels - 98.72%/98.72%
to
[01] | levels - 99.03%/40.54%
(I don't know if this is intended or must be considered)

If you consider it, you get a total value of 11.52% / 40.54% * 100% = ~30% from the total server performance. This represents an increase by 4x.

Nevertheless the pathfinding seems to use unexpected much performance:
1.14
[12] | | | | | | | | | | | | pathfind - 96.67%/8.01%

1.13.2
[11] | | | | | | | | | | | pathfind - 82.80%/0.50%

Because of the fact that the golems are staying on a 1x1 block and are completely surrounded by a gap they definetly can't pass I would expect a much lower value in 1.14.