Wedhro

Confirmed in 1.9.

"fixed"
I can't even play 1.9. After a few minutes of acceptable performances it goes down to 0-1 FPS for a few minutes. I just wait until the CPU is no longer struggling (it goes up to 100% usage) and then it runs ok for a few minutes, until it starts lagging again. And again.
It's unplayable, and this machine could run anything from beta 1.2 to release 1.8.

I already posted crash logs and such, in case you're wondering.

Also, Fancy and Fast versions of leaves. It would make much sense if those would be split in 2 different models, also because any leaf model which is not a perfect 1x1x1 cube will act as an "x ray" block.

You're probably right; it's just disappointing, as usual.

Ferns and vines not fading is only half the problem (which I didn't ever notice BTW), the "bug" reported here was about all biome transitions, including grass, leaves etc. Of course I'm using snapshot 16w07b, as you can see in the pic I uplodad, the one with the plains/savanna transition: the fade is still really short, I can just see 2 intermediate colors between the plains' green and the savanna's brown.

It's not really a bug so there's no expected result. Colors just change too abruptly since Anvil was introduced, and if it's marked as fixed I expect it to be fixed.

I don't see why this is been marked as 'fixed' because I still see only 2-3 intermediate colors between different biomes, as you can see in this plains-savanna transition.

Snapshots 15w39a-c fixed the issue for me: from 9 FPS to 12-23 FPS when moving, averaging 20 on already existing chunks, and that's even better than what I got with 1.8.8.

Nope, crashed again. I give up.

I tried once more and the launcher started (without any special workaround), here's the log:

Bootstrap (v5)
Current time is Sep 13, 2015 1:56:09 PM
System.getProperty('os.name') == 'Linux'
System.getProperty('os.version') == '3.13.0-24-generic'
System.getProperty('os.arch') == 'amd64'
System.getProperty('java.version') == '1.8.0_51'
System.getProperty('java.vendor') == 'Oracle Corporation'
System.getProperty('sun.arch.data.model') == '64'

Looking for update
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma
Didn't find an update in time.
Reversing LZMA on /home/wedhro/.minecraft/launcher.pack.lzma to /home/wedhro/.minecraft/launcher.pack
Unpacking /home/wedhro/.minecraft/launcher.pack to /home/wedhro/.minecraft/launcher.jar
Cleaning up /home/wedhro/.minecraft/launcher.pack
Starting launcher.
[13:56:21 INFO]: Minecraft Launcher 1.6.44 (through bootstrap 5) started on linux...
[13:56:21 INFO]: Current time is Sep 13, 2015 1:56:21 PM
[13:56:21 INFO]: System.getProperty('os.name') == 'Linux'
[13:56:21 INFO]: System.getProperty('os.version') == '3.13.0-24-generic'
[13:56:21 INFO]: System.getProperty('os.arch') == 'amd64'
[13:56:21 INFO]: System.getProperty('java.version') == '1.8.0_51'
[13:56:21 INFO]: System.getProperty('java.vendor') == 'Oracle Corporation'
[13:56:21 INFO]: System.getProperty('sun.arch.data.model') == '64'
[13:56:21 INFO]: proxy == DIRECT
[13:56:21 INFO]: JFX is already initialized
[13:56:22 INFO]: Refreshing local version list...
Got reply in: 14705ms
No update found.
[13:56:25 INFO]: Refreshing remote version list...
[13:56:25 INFO]: Refresh complete.
[13:56:26 INFO]: Loaded 18 profile(s); selected '1.8.8 OptiFine F2'
[13:56:26 INFO]: Refreshing auth...
[13:56:26 INFO]: Logging in with access token

(java:7780): Gtk-WARNING **: Unable to locate theme engine in module_path: "oxygen-gtk",

I know nobody cares here but maybe a little more detail could help them fix this erratic mess.

The workaround didn't work:

Error: impossible to find or load the main class Dswing.systemlaf=javax.swing.plaf.metal.MetalLookAndFeel

BTW I can't believe it's never Mojang's fault: they updated the launcher and it no longer works, how can it be someone else's responsibility? I'm not even using OpenJDK, that's the latest version of Java from Oracle.

Confirmed in 15w36c

1) Summoned an iron golem in a confined area (in the open or underground is the same)
2) Spawned a few sheeps, horses and villagers in the same area. Nothing happens.
3) Spawned a few zombies. The golem went aggro against the zombies and against passive mobs. It seems to stop when no eligible target is in its range. Not sure if it picks zombies before other mobs or not.

Confirmed to happen in 15w35a too. Optimizations didn't produce any visible difference compared to previous snapshots.

Still happens in 15w33c. The framerate went up by a few FPS (from 9 to 12), but still video options don't matter i.e. I get almost the same FPS at 10 view distance with every graphic option turned on and at 2 view distance with everything turned off.
The only thing that gives more FPS still consists on resizing down the window. Nothing else matter.
Again, CPU load barely goes above 50% while it used to go up to 99% in all previous versions of the game since beta 1.2.

I already posted some crash logs, let me know if you need one even for this snapshot.

EDIT: the FPS didn't go up, I just forgot I had the window resized down.

Confirmed to happen in 15w33b too. The console no longer spams UUID errors but the framerate is still 9 FPS as in previous 1.9 snapshots, while it was about 20 in previous versions.

The weirdest thing is that video options still don't matter: I get that framerate both at render distance 8 with all options on, and at render distance 2 with everything turned off; turning on and off VBO doesn't change anything.

The only things that makes the framerate go higher is resizing the window, and then the video options start making a difference again. Never saw something like that happening.

---- Minecraft Crash Report ----
// This is a token for 1 free hug. Redeem at your nearest Mojangsta: [~~HUG~~]

Time: 12/08/15 18.28
Description: Manually triggered debug crash

java.lang.Throwable
	at ayt.s(SourceFile:1569)
	at ayt.au(SourceFile:877)
	at ayt.a(SourceFile:326)
	at net.minecraft.client.main.Main.main(SourceFile:125)


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

-- Head --
Stacktrace:
	at bgv.a(SourceFile:314)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bit['Wedhro'/483, l='MpServer', x=170,88, y=74,00, z=196,01]]
	Chunk stats: MultiplayerChunkCache: 49, 49
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: 164,00,64,00,256,00 - World: (164,64,256), Chunk: (at 4,4,0 in 10,16; contains blocks 160,0,256 to 175,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 4691 game time, 4691 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: 86 total; [ya['Skeleton'/256, l='MpServer', x=162,22, y=35,00, z=161,78], vh['Squid'/512, l='MpServer', x=108,50, y=59,75, z=174,84], ux['Cow'/259, l='MpServer', x=166,97, y=68,00, z=215,94], ut['Bat'/260, l='MpServer', x=159,21, y=16,05, z=248,35], ut['Bat'/261, l='MpServer', x=176,75, y=20,07, z=223,89], ye['Zombie'/274, l='MpServer', x=177,47, y=35,00, z=172,94], wz['item.item.seeds'/1042, l='MpServer', x=185,16, y=39,01, z=141,59], ux['Cow'/276, l='MpServer', x=177,75, y=70,00, z=218,72], ux['Cow'/277, l='MpServer', x=180,09, y=68,00, z=222,88], ve['Sheep'/280, l='MpServer', x=183,78, y=64,00, z=269,78], ve['Sheep'/281, l='MpServer', x=177,03, y=64,00, z=271,06], ve['Sheep'/282, l='MpServer', x=186,19, y=64,00, z=266,72], ve['Sheep'/283, l='MpServer', x=185,88, y=64,00, z=267,88], ux['Cow'/291, l='MpServer', x=203,47, y=74,00, z=142,22], ux['Cow'/292, l='MpServer', x=202,38, y=64,00, z=143,34], ye['Zombie'/293, l='MpServer', x=203,50, y=64,00, z=142,88], wz['item.item.slimeball'/294, l='MpServer', x=206,31, y=31,00, z=156,81], ux['Cow'/295, l='MpServer', x=202,47, y=62,33, z=145,78], ux['Cow'/296, l='MpServer', x=205,50, y=76,00, z=144,50], ux['Cow'/297, l='MpServer', x=200,28, y=68,00, z=169,53], ux['Cow'/298, l='MpServer', x=206,47, y=71,00, z=185,72], ux['Cow'/299, l='MpServer', x=202,75, y=71,00, z=185,25], ux['Cow'/300, l='MpServer', x=206,00, y=71,00, z=206,06], ya['Skeleton'/304, l='MpServer', x=212,50, y=15,00, z=150,50], xn['Creeper'/305, l='MpServer', x=214,31, y=27,00, z=154,94], ux['Cow'/308, l='MpServer', x=209,72, y=69,00, z=174,22], ux['Cow'/309, l='MpServer', x=209,50, y=70,00, z=186,50], ux['Cow'/310, l='MpServer', x=214,25, y=68,00, z=186,53], ux['Cow'/311, l='MpServer', x=210,78, y=69,00, z=186,50], ux['Cow'/312, l='MpServer', x=219,44, y=64,00, z=178,25], ux['Cow'/313, l='MpServer', x=214,53, y=71,00, z=202,97], ux['Cow'/314, l='MpServer', x=211,53, y=67,00, z=210,53], ux['Cow'/315, l='MpServer', x=209,94, y=68,00, z=210,69], xn['Creeper'/316, l='MpServer', x=208,50, y=56,00, z=240,50], ye['Zombie'/317, l='MpServer', x=210,50, y=55,00, z=241,50], ye['Zombie'/320, l='MpServer', x=231,50, y=12,00, z=135,50], xn['Creeper'/325, l='MpServer', x=224,50, y=34,00, z=161,50], ye['Zombie'/326, l='MpServer', x=233,19, y=35,00, z=171,50], ye['Zombie'/328, l='MpServer', x=229,75, y=36,00, z=174,66], ye['Zombie'/329, l='MpServer', x=239,50, y=44,00, z=190,50], ux['Cow'/346, l='MpServer', x=248,75, y=69,00, z=128,28], ye['Zombie'/1417, l='MpServer', x=121,50, y=30,00, z=145,50], ya['Skeleton'/1180, l='MpServer', x=97,50, y=48,00, z=166,50], ya['Skeleton'/160, l='MpServer', x=94,22, y=47,00, z=163,28], ya['Skeleton'/162, l='MpServer', x=95,56, y=48,00, z=162,69], ux['Cow'/163, l='MpServer', x=94,25, y=69,00, z=166,72], ye['Zombie'/173, l='MpServer', x=104,03, y=48,00, z=140,59], ut['Bat'/175, l='MpServer', x=109,25, y=16,10, z=155,75], ye['Zombie'/177, l='MpServer', x=96,50, y=47,00, z=166,50], ux['Cow'/178, l='MpServer', x=97,56, y=70,00, z=165,59], ux['Cow'/179, l='MpServer', x=99,78, y=70,00, z=163,50], ux['Cow'/180, l='MpServer', x=99,50, y=69,00, z=165,50], ye['Zombie'/181, l='MpServer', x=103,50, y=37,00, z=184,50], ut['Bat'/183, l='MpServer', x=97,88, y=18,55, z=218,82], ut['Bat'/184, l='MpServer', x=107,00, y=48,11, z=257,08], ux['Cow'/187, l='MpServer', x=113,19, y=71,00, z=140,66], ux['Cow'/188, l='MpServer', x=117,13, y=71,00, z=143,50], ux['Cow'/190, l='MpServer', x=118,63, y=71,00, z=144,63], ye['Zombie'/1470, l='MpServer', x=123,78, y=37,81, z=209,28], ux['Cow'/191, l='MpServer', x=115,50, y=71,00, z=144,50], wz['item.tile.doublePlant.rose'/192, l='MpServer', x=116,91, y=62,00, z=175,22], wz['item.tile.doublePlant.rose'/194, l='MpServer', x=116,00, y=64,00, z=181,03], yc['Spider'/1224, l='MpServer', x=232,50, y=33,00, z=187,50], ya['Skeleton'/211, l='MpServer', x=131,34, y=33,00, z=184,84], xn['Creeper'/214, l='MpServer', x=129,50, y=48,00, z=189,50], wz['item.item.rottenFlesh'/1238, l='MpServer', x=230,09, y=63,00, z=138,56], xn['Creeper'/215, l='MpServer', x=132,50, y=48,00, z=185,50], ux['Cow'/216, l='MpServer', x=133,19, y=78,00, z=171,16], ux['Cow'/218, l='MpServer', x=138,94, y=73,00, z=253,00], ux['Cow'/219, l='MpServer', x=121,75, y=68,00, z=245,38], bit['Wedhro'/483, l='MpServer', x=170,88, y=74,00, z=196,01], ya['Skeleton'/1508, l='MpServer', x=149,50, y=30,00, z=167,50], ya['Skeleton'/1509, l='MpServer', x=147,50, y=30,00, z=165,50], ut['Bat'/231, l='MpServer', x=148,50, y=45,10, z=185,25], ux['Cow'/232, l='MpServer', x=155,46, y=72,00, z=185,90], ux['Cow'/233, l='MpServer', x=148,22, y=72,00, z=176,81], ux['Cow'/234, l='MpServer', x=149,28, y=72,00, z=189,22], ya['Skeleton'/235, l='MpServer', x=145,50, y=45,00, z=201,50], ya['Skeleton'/1516, l='MpServer', x=151,50, y=46,00, z=200,50], ux['Cow'/237, l='MpServer', x=145,13, y=69,00, z=206,97], ux['Cow'/238, l='MpServer', x=139,06, y=73,00, z=251,00], ux['Cow'/239, l='MpServer', x=148,03, y=64,00, z=260,97], yd['Witch'/1273, l='MpServer', x=137,50, y=35,00, z=174,50], ut['Bat'/254, l='MpServer', x=179,88, y=17,10, z=161,28], ya['Skeleton'/255, l='MpServer', x=172,13, y=35,00, z=171,47], vh['Squid'/511, l='MpServer', x=108,50, y=61,88, z=179,22]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bgv.a(SourceFile:314)
	at ayt.b(SourceFile:2301)
	at ayt.a(SourceFile:335)
	at net.minecraft.client.main.Main.main(SourceFile:125)

-- System Details --
Details:
	Minecraft Version: 15w33b
	Operating System: Linux (amd64) version 3.13.0-24-generic
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 109404344 bytes (104 MB) / 347471872 bytes (331 MB) up to 1060372480 bytes (1011 MB)
	JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Launched Version: 15w33b
	LWJGL: 2.9.4
	OpenGL: Gallium 0.4 on AMD RS780 GL version 3.0 Mesa 10.1.0, X.Org
	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: Yes
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: 
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	CPU: 2x AMD Turion(tm)X2 Dual Core Mobile RM-70

Confirmed it happening in 15w32a. Lot of "Tried to add entity (whatever) with duplicate UUID" errors.

Here's my crash log:

---- Minecraft Crash Report ----
// Shall we play a game?

Time: 06/08/15 0.06
Description: Manually triggered debug crash

java.lang.Throwable
	at axz.s(SourceFile:1566)
	at axz.at(SourceFile:874)
	at axz.a(SourceFile:323)
	at net.minecraft.client.main.Main.main(SourceFile:125)


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

-- Head --
Stacktrace:
	at bfy.a(SourceFile:309)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bhw['Wedhro'/208, l='MpServer', x=-243,66, y=64,00, z=287,74]]
	Chunk stats: MultiplayerChunkCache: 225, 225
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: -256,00,64,00,232,00 - World: (-256,64,232), Chunk: (at 0,4,8 in -16,14; contains blocks -256,0,224 to -241,255,239), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 1391 game time, 1391 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: 69 total; [xn['Zombie'/2072, l='MpServer', x=-218,50, y=24,00, z=209,50], ud['Bat'/10271, l='MpServer', x=-214,41, y=43,38, z=225,06], un['Rabbit'/36, l='MpServer', x=-324,72, y=71,00, z=349,09], ug['Chicken'/43, l='MpServer', x=-285,50, y=70,00, z=367,50], ug['Chicken'/44, l='MpServer', x=-285,50, y=70,00, z=365,50], ug['Chicken'/45, l='MpServer', x=-284,50, y=70,00, z=364,50], ww['Creeper'/10293, l='MpServer', x=-191,50, y=52,00, z=349,50], un['Rabbit'/55, l='MpServer', x=-305,41, y=64,00, z=350,56], ww['Creeper'/10295, l='MpServer', x=-189,50, y=52,00, z=352,50], un['Rabbit'/58, l='MpServer', x=-256,91, y=64,00, z=269,06], un['Rabbit'/59, l='MpServer', x=-249,66, y=63,00, z=264,34], un['Rabbit'/60, l='MpServer', x=-251,31, y=68,00, z=256,13], un['Rabbit'/78, l='MpServer', x=-224,50, y=66,00, z=225,50], un['Rabbit'/79, l='MpServer', x=-222,66, y=66,00, z=224,34], un['Rabbit'/80, l='MpServer', x=-223,66, y=66,00, z=224,34], un['Rabbit'/81, l='MpServer', x=-221,50, y=63,00, z=301,50], un['Rabbit'/82, l='MpServer', x=-216,41, y=63,00, z=295,28], un['Rabbit'/83, l='MpServer', x=-212,28, y=64,00, z=298,50], ug['Chicken'/84, l='MpServer', x=-217,63, y=63,00, z=303,53], ug['Chicken'/85, l='MpServer', x=-225,81, y=62,53, z=302,94], ug['Chicken'/86, l='MpServer', x=-222,44, y=63,00, z=301,16], ug['Chicken'/87, l='MpServer', x=-222,59, y=63,00, z=301,81], un['Rabbit'/103, l='MpServer', x=-201,50, y=66,00, z=234,50], un['Rabbit'/104, l='MpServer', x=-212,41, y=64,00, z=231,56], un['Rabbit'/105, l='MpServer', x=-206,66, y=65,00, z=233,34], xn['Zombie'/8311, l='MpServer', x=-199,50, y=29,00, z=210,06], ww['Creeper'/8318, l='MpServer', x=-166,00, y=16,00, z=288,44], ww['Creeper'/8319, l='MpServer', x=-170,13, y=16,00, z=292,22], ud['Bat'/10396, l='MpServer', x=-287,06, y=13,53, z=352,00], bhw['Wedhro'/208, l='MpServer', x=-243,66, y=64,00, z=287,74], ur['Squid'/242, l='MpServer', x=-272,53, y=61,47, z=308,13], ww['Creeper'/10482, l='MpServer', x=-228,41, y=22,00, z=250,97], ur['Squid'/243, l='MpServer', x=-264,88, y=61,00, z=308,74], ur['Squid'/244, l='MpServer', x=-262,88, y=61,00, z=297,52], ur['Squid'/245, l='MpServer', x=-261,35, y=61,78, z=305,70], ur['Squid'/279, l='MpServer', x=-290,16, y=59,19, z=232,13], ur['Squid'/281, l='MpServer', x=-284,94, y=54,81, z=233,44], ur['Squid'/298, l='MpServer', x=-304,16, y=58,13, z=231,31], ww['Creeper'/10555, l='MpServer', x=-241,50, y=37,00, z=333,50], xj['Skeleton'/10617, l='MpServer', x=-282,50, y=15,00, z=349,50], ud['Bat'/398, l='MpServer', x=-214,66, y=43,78, z=228,13], xn['Zombie'/10674, l='MpServer', x=-177,50, y=25,00, z=239,50], xn['Zombie'/10675, l='MpServer', x=-174,50, y=25,00, z=244,09], ww['Creeper'/500, l='MpServer', x=-245,50, y=28,00, z=249,50], ud['Bat'/10741, l='MpServer', x=-231,53, y=23,41, z=233,56], ud['Bat'/10802, l='MpServer', x=-188,59, y=37,10, z=337,91], xl['Spider'/10875, l='MpServer', x=-224,50, y=32,00, z=237,50], xl['Spider'/10877, l='MpServer', x=-226,50, y=32,00, z=238,50], ww['Creeper'/13078, l='MpServer', x=-164,28, y=34,00, z=317,91], xj['Skeleton'/11034, l='MpServer', x=-183,50, y=34,00, z=314,50], xl['Spider'/848, l='MpServer', x=-197,72, y=25,09, z=212,28], xn['Zombie'/850, l='MpServer', x=-205,50, y=24,00, z=212,50], wi['item.item.arrow'/9066, l='MpServer', x=-235,88, y=27,00, z=242,94], ww['Creeper'/1021, l='MpServer', x=-200,50, y=38,00, z=296,50], xj['Skeleton'/1055, l='MpServer', x=-253,50, y=25,00, z=223,50], ud['Bat'/13444, l='MpServer', x=-226,38, y=21,50, z=251,47], ud['Bat'/9350, l='MpServer', x=-185,47, y=35,38, z=209,09], ud['Bat'/9351, l='MpServer', x=-188,09, y=34,10, z=239,66], xj['Skeleton'/1245, l='MpServer', x=-233,41, y=16,00, z=219,69], xl['Spider'/13540, l='MpServer', x=-186,50, y=33,00, z=214,50], xn['Zombie'/11793, l='MpServer', x=-202,50, y=13,00, z=316,50], xl['Spider'/1638, l='MpServer', x=-184,50, y=25,00, z=306,50], xj['Skeleton'/9837, l='MpServer', x=-210,50, y=16,00, z=321,50], ww['Creeper'/1741, l='MpServer', x=-177,50, y=45,00, z=295,50], xn['Zombie'/12001, l='MpServer', x=-236,13, y=16,50, z=220,16], xn['Zombie'/10194, l='MpServer', x=-189,50, y=18,00, z=216,50], xj['Skeleton'/10197, l='MpServer', x=-189,50, y=18,00, z=215,50], xn['Zombie'/10208, l='MpServer', x=-187,50, y=31,00, z=251,50], xn['Zombie'/10209, l='MpServer', x=-185,50, y=31,00, z=260,50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bfy.a(SourceFile:309)
	at axz.b(SourceFile:2293)
	at axz.a(SourceFile:332)
	at net.minecraft.client.main.Main.main(SourceFile:125)

-- System Details --
Details:
	Minecraft Version: 15w32a
	Operating System: Linux (amd64) version 3.13.0-24-generic
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 194667376 bytes (185 MB) / 406134784 bytes (387 MB) up to 1060372480 bytes (1011 MB)
	JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
	Launched Version: 15w32a
	LWJGL: 2.9.4
	OpenGL: Gallium 0.4 on AMD RS780 GL version 3.0 Mesa 10.1.0, X.Org
	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: Yes
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: Pixel Reality WIP
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	CPU: 2x AMD Turion(tm)X2 Dual Core Mobile RM-70

I noticed that reducing the size of the window from maximized/fullscreen gives a lot more FPS even if reduced as much as 3/4 of the screen, while on previous versions this method didn't help much.

I'm not complaining, I'm just here to help because how can they fix stuff if nobody tells them stuff is broken? Also, search feature needs some refinement, I searched for "lag" in 14w25 before posting this and nothing showed up.

PS: you may want to tell the other guy about the particles thing, the issue is definitely dependent on it.

I know the system needs updates and I'm actually switching to a different OS soon, the point here is that this didn't happen at all until 14w25a, and I'm playing MC since beta 1.2.

I just found out it only happens when particles are not set to "minimal", regardless of other options. The following crash was forced while at Fast/No Smooth Lighting/2 chuncks Render Distance, No Bobbing and No Clouds.

Minecraft Crash Report ----
// Oh - I know what I did wrong!

Time: 20/06/14 13.54
Description: Manually triggered debug crash

java.lang.Throwable
at blj.q(SourceFile:1539)
at blj.ap(SourceFile:861)
at blj.a(SourceFile:303)
at net.minecraft.client.main.Main.main(SourceFile:121)

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

– Head –
Stacktrace:
at bya.a(SourceFile:310)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [cby['Wedhro'/412260, l='MpServer', x=162,61, y=59,61, z=287,38]]
Chunk stats: MultiplayerChunkCache: 30, 30
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: -60,00,64,00,136,00 - World: (-60,64,136), Chunk: (at 4,4,8 in -4,8; contains blocks -64,0,128 to -49,255,143), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 17622 game time, 17622 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: 9 total; [aca['Ragno'/1073904, l='MpServer', x=201,47, y=62,09, z=265,53], aan['Creeper'/1113894, l='MpServer', x=182,50, y=63,00, z=257,50], cby['Wedhro'/412260, l='MpServer', x=162,61, y=59,61, z=287,38], acf['Zombi'/1088955, l='MpServer', x=195,28, y=20,00, z=296,88], aap['Enderman'/1067083, l='MpServer', x=191,53, y=31,00, z=293,22], acf['Zombi'/1157555, l='MpServer', x=187,50, y=63,00, z=257,50], yn['Pipistrello'/1050645, l='MpServer', x=189,42, y=25,26, z=331,23], acf['Zombi'/1048379, l='MpServer', x=186,47, y=23,00, z=304,41], acf['Zombi'/1066033, l='MpServer', x=196,50, y=63,00, z=265,50]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at bya.a(SourceFile:310)
at blj.b(SourceFile:2134)
at blj.a(SourceFile:312)
at net.minecraft.client.main.Main.main(SourceFile:121)

– System Details –
Details:
Minecraft Version: 14w25b
Operating System: Linux (i386) version 3.12.8-desktop586-2.mga4
Java Version: 1.7.0_45, Oracle Corporation
Java VM Version: OpenJDK Client VM (mixed mode), Oracle Corporation
Memory: 127423552 bytes (121 MB) / 453017600 bytes (432 MB) up to 518979584 bytes (494 MB)
JVM Flags: 1 total; -Xmx512M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Launched Version: 14w25b
LWJGL: 2.9.1
OpenGL: Gallium 0.4 on AMD RS780 GL version 2.1 Mesa 10.0.2, X.Org
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because ARB_framebuffer_object is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.

Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: []
Current Language: Italiano (Italia)
Profiler Position: N/A (disabled)

It happens on fresh worlds and it doesn't matter if an underwater temple is near or not, I still experience lag. Also, lot of mobs never gave me problems; by chance today my little niece spammed around 50 villagers in 1.7.10-pre2 and there was no lag at all.