I didn't have time to test this, the A -> B transfer brought too much change and too fast.
On 14w29b using VBOs lovered my FPS from 28 -> 16 while, 0 chunk updates view distance maximum, on server side and client, all chunks where loaded.
Gone on 14w28a
Sometimes it spits out this 2
java.util.ConcurrentModificationException
at java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1115)
at java.util.TreeMap$KeyIterator.next(TreeMap.java:1169)
at pb.a(SourceFile:557)
at pb.a(SourceFile:537)
at bah.a(SourceFile:258)
at bah.a(SourceFile:113)
at pa.b(SourceFile:167)
at pa.a(SourceFile:210)
at pb.a(SourceFile:739)
at net.minecraft.server.MinecraftServer.a(SourceFile:340)
at net.minecraft.server.MinecraftServer.p(SourceFile:363)
at nq.run(SourceFile:691)
Has nothing to do with the world, I just encountered this same issue on my linux server tried 1.8 and 1.7 Java.
I always start the snapshot with a fresh world.
java.util.ConcurrentModificationException
at java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1115)
at java.util.TreeMap$KeyIterator.next(TreeMap.java:1169)
at pb.a(SourceFile:557)
at pb.a(SourceFile:537)
at bah.a(SourceFile:258)
at bah.a(SourceFile:113)
at pa.b(SourceFile:167)
at pa.a(SourceFile:210)
at pb.a(SourceFile:739)
at net.minecraft.server.MinecraftServer.a(SourceFile:340)
at net.minecraft.server.MinecraftServer.p(SourceFile:363)
at nq.run(SourceFile:691)
if I try to ctrl+c it sometimes spits this out.
Confirmed for 1.13-pre8
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