In 1.4.7 I would receive 60-80fps with a HD texture pack, however as of 1.5 I have dropped to 40-60fps on a standard pack and 30fps with a HD pack. I am also now unable to record footage of my mods. I tried 13w12~ along with 1.5.1 and while 13w12~ reduced lag slightly I was still unable to hold 30fps up constantly while recording. I also receive lag spikes that shoot up to 100fps then back down to low levels and up to around 50fps again. I believe this problem is to do with the improved lighting engine in 1.5

---- Minecraft Crash Report ----
// Oops.

Time: 20/03/13 00:43
Description: Manually triggered debug crash

java.lang.Throwable
at net.minecraft.client.Minecraft.l(SourceFile:1162)
at net.minecraft.client.Minecraft.K(SourceFile:572)
at net.minecraft.client.Minecraft.run(SourceFile:524)
at java.lang.Thread.run(Unknown Source)

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

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [bdw['bmanrules'/1, l='MpServer', x=1999.54, y=57.62, z=-302.44]]
Chunk stats: MultiplayerChunkCache: 441
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options:
Level spawn location: World: (1996,4,-298), Chunk: (at 12,0,6 in 124,-19; contains blocks 1984,0,-304 to 1999,255,-289), Region: (3,-1; contains chunks 96,-32 to 127,-1, blocks 1536,0,-512 to 2047,255,-1)
Level time: 3053 game time, 3053 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; [rf['Boat'/0, l='MpServer', x=2006.72, y=56.28, z=-308.06], bdw['bmanrules'/1, l='MpServer', x=1999.54, y=57.62, z=-302.44]]
Retry entities: 0 total; []
Stacktrace:
at bdt.a(SourceFile:282)
at net.minecraft.client.Minecraft.b(SourceFile:1887)
at net.minecraft.client.Minecraft.run(SourceFile:533)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 13w12~
Operating System: Windows 8 (amd64) version 6.2
Java Version: 1.7.0_17, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 425691768 bytes (405 MB) / 648740864 bytes (618 MB) up to 954466304 bytes (910 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 9635 (539560 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
LWJGL: 2.4.2
OpenGL: Intel(R) HD Graphics 4000 GL version 4.0.0 - Build 9.17.10.2875, Intel
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Texture Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: 47 (2632 bytes; 0 MB) allocated, 13 (728 bytes; 0 MB) used