This bug occurs only in 1.9, lagging the game crazy. Even on the
title screen. By adjusting the screen options in my game, I can only boost
the FPS to a unstable 10 FPS. This issue occurred just a few days after
1.9 came out, and its been affecting my game ever since, in Single player,
and multiplayer as well. This issue has some of the properties of my
last reported issue, as rarely, the game's speed has the consistency
of slow mo, with freezes very often. I Noticed that also, when I pressed
f3, I saw that not only my FPS was down, but also that there was
no chunk updates, and even if there were, they were too quick
for my eyes to even notice them. I'm afraid there isn't any way that I have
found to make this bug to happen, nor do I think there is much to do
with my computer, because I increased my RAM to 3G for Minecraft,
like a Staff member told me to-do before. Even though, I saw that
out of 3059MB, only about 6-7% was allocated. Is there any way to
increase the allocation?

P.S I brought you a crash report in advance.

---- Minecraft Crash Report ----
// But it works on my machine.

Time: 3/3/16 9:22 PM
Description: Manually triggered debug crash

java.lang.Throwable
at bcf.az(SourceFile:1694)
at bcf.t(SourceFile:1615)
at bcf.av(SourceFile:962)
at bcf.a(SourceFile:392)
at net.minecraft.client.main.Main.main(SourceFile:124)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Stacktrace:
at bcf.az(SourceFile:1694)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [bmt['Talon687'/19, l='MpServer', x=-32.50, y=4.00, z=339.50]]
Chunk stats: MultiplayerChunkCache: 2656, 2656
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options:
Level spawn location: World: (-28,4,347), Chunk: (at 4,0,11 in -2,21; contains blocks -32,0,336 to -17,255,351), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 208 game time, 208 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
Forced entities: 2 total; [bmt['Talon687'/19, l='MpServer', x=-32.50, y=4.00, z=339.50], yx['Slime'/28253, l='MpServer', x=18.82, y=4.00, z=374.04]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at bku.a(SourceFile:365)
at bcf.b(SourceFile:2515)
at bcf.a(SourceFile:401)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.9
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 181130592 bytes (172 MB) / 423772160 bytes (404 MB) up to 3207856128 bytes (3059 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx3G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.9
LWJGL: 2.9.4
OpenGL: Intel(R) HD Graphics 4400 GL version 4.3.0 - Build 10.18.15.4248, Intel
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: Canadian English (Canada)
Profiler Position: N/A (disabled)
CPU: 4x Intel(R) Core(TM) i5-4210U CPU @ 1.70GHz

Maybe you can find some info to help me?
-Talon687