EDIT:
You just have to not delete VBOs when switching worlds. This bug exists even on Windows 10 on Hypixel. On every platform. Render distance 32 makes the lag longer.

Detailed info:

Create an unordered stack with objects that have indexes inside. Addictional stack index points to the top of used elements stack. When deleting VBO just remove it from the used stack and "transfer to ununsed" stack. Java code as a proof of concept in comments
Minor improvement: please remove System.gc() when switching worlds
 

(end of edit)

When I switch the world (1.9.3-pre1) or teleport between servers on a proxy server (1.9.2) the game freezes in dirt screen (no text showing).
When switching nether<->overworld it takes about 8 seconds every time. On my proxy it takes sometimes 100s.
Here's a snapshot of CPU time when joining my server. Which sends 4 respawn packets. On Windows 10 both switching world and server work perfectly.
I have no resource packs, just freshly installed system.
On calltree it looks like it's something with glGenLists()