Minecraft used 1gb more ram than it did when I started it up 30 minutes earlier

I would assume a memory leak, at first I thought it was my 20+ mods, but I got the same problem with vanilla MineCraft, using different launchers. (MagicLauncher, MCP and Vanilla) This crash report is in MCP.

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

Time: 4/13/13 5:28 PM
Description: Manually triggered debug crash

java.lang.Throwable
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:1597)
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:828)
	at net.minecraft.client.Minecraft.run(Minecraft.java:753)
	at java.lang.Thread.run(Thread.java:722)


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; [EntityClientPlayerMP['Player671'/602828, l='MpServer', x=50.00, y=83.52, z=-2627.69]]
	Chunk stats: MultiplayerChunkCache: 441
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (72,64,244), Chunk: (at 8,4,4 in 4,15; contains blocks 64,0,240 to 79,255,255), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 146609 game time, 66192 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: true), thunder time: 0 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 135 total; [EntityFallingSand['Falling Block'/617645, l='MpServer', x=93.50, y=19.42, z=-2596.50], EntityFallingSand['Falling Block'/617670, l='MpServer', x=93.50, y=18.92, z=-2596.50], EntityItem['item.tile.gravel'/617473, l='MpServer', x=70.25, y=27.13, z=-2598.97], EntityItem['item.tile.rail'/623366, l='MpServer', x=81.59, y=22.13, z=-2587.13], EntityBat['Bat'/615585, l='MpServer', x=1.16, y=53.10, z=-2590.56], EntityZombie['Zombie'/615672, l='MpServer', x=-28.93, y=29.00, z=-2558.70], EntityCow['Cow'/615664, l='MpServer', x=9.50, y=64.00, z=-2656.13], EntityCow['Cow'/615665, l='MpServer', x=9.88, y=64.00, z=-2659.50], EntityCow['Cow'/615668, l='MpServer', x=111.00, y=63.00, z=-2662.66], EntitySpider['Spider'/615670, l='MpServer', x=-25.19, y=29.83, z=-2557.50], EntitySkeleton['Skeleton'/615671, l='MpServer', x=-24.00, y=29.00, z=-2557.50], EntityCow['Cow'/615663, l='MpServer', x=9.50, y=64.00, z=-2657.84], EntityCow['Cow'/615662, l='MpServer', x=8.16, y=64.00, z=-2659.50], EntityChicken['Chicken'/615701, l='MpServer', x=43.50, y=74.00, z=-2687.50], EntityChicken['Chicken'/615703, l='MpServer', x=46.50, y=73.00, z=-2686.50], EntityChicken['Chicken'/615702, l='MpServer', x=42.47, y=73.00, z=-2696.44], EntitySkeleton['Skeleton'/615765, l='MpServer', x=-2.50, y=64.00, z=-2700.50], EntitySkeleton['Skeleton'/615768, l='MpServer', x=-2.50, y=64.00, z=-2702.50], EntityCreeper['Creeper'/615773, l='MpServer', x=-18.50, y=40.00, z=-2600.50], EntityCreeper['Creeper'/615772, l='MpServer', x=-19.50, y=41.00, z=-2607.03], EntityCow['Cow'/615847, l='MpServer', x=114.03, y=63.00, z=-2660.00], EntityCow['Cow'/615846, l='MpServer', x=112.25, y=63.00, z=-2661.50], EntityCow['Cow'/615845, l='MpServer', x=112.84, y=63.00, z=-2662.63], EntityItem['item.tile.gravel'/617770, l='MpServer', x=89.78, y=18.13, z=-2594.22], EntityItem['item.tile.gravel'/617771, l='MpServer', x=91.81, y=22.13, z=-2588.50], EntityItem['item.tile.gravel'/617769, l='MpServer', x=89.28, y=18.13, z=-2596.00], EntitySkeleton['Skeleton'/615875, l='MpServer', x=-2.50, y=53.00, z=-2590.50], EntitySkeleton['Skeleton'/615876, l='MpServer', x=-0.50, y=53.00, z=-2589.50], EntityZombie['Zombie'/615889, l='MpServer', x=61.50, y=68.00, z=-2581.50], EntitySkeleton['Skeleton'/615890, l='MpServer', x=31.38, y=63.00, z=-2608.16], EntitySkeleton['Skeleton'/615892, l='MpServer', x=31.50, y=63.00, z=-2605.50], EntitySkeleton['Skeleton'/615893, l='MpServer', x=28.56, y=63.00, z=-2612.09], EntityZombie['Zombie'/615895, l='MpServer', x=27.50, y=63.00, z=-2598.50], EntityFallingSand['Falling Block'/621647, l='MpServer', x=155.50, y=29.66, z=-2556.50], EntityCreeper['Creeper'/615957, l='MpServer', x=26.19, y=71.00, z=-2686.63], EntitySkeleton['Skeleton'/615951, l='MpServer', x=128.50, y=48.00, z=-2606.50], EntityBat['Bat'/616055, l='MpServer', x=57.07, y=49.85, z=-2705.90], EntityItem['item.tile.rail'/623060, l='MpServer', x=70.88, y=18.13, z=-2596.78], EntityFallingSand['Falling Block'/623087, l='MpServer', x=93.50, y=19.65, z=-2596.50], EntityBat['Bat'/616126, l='MpServer', x=42.75, y=21.10, z=-2575.75], EntityBat['Bat'/616113, l='MpServer', x=-31.47, y=22.10, z=-2635.22], EntityCreeper['Creeper'/616099, l='MpServer', x=120.50, y=64.00, z=-2707.50], EntityItem['item.tile.rail'/622880, l='MpServer', x=75.85, y=17.13, z=-2620.87], EntitySquid['Squid'/616082, l='MpServer', x=110.50, y=60.00, z=-2570.50], EntityBat['Bat'/616079, l='MpServer', x=103.17, y=54.00, z=-2681.04], EntityBat['Bat'/616066, l='MpServer', x=-21.19, y=42.86, z=-2591.66], EntityZombie['Zombie'/616152, l='MpServer', x=103.50, y=53.00, z=-2693.50], EntityZombie['Zombie'/616153, l='MpServer', x=103.50, y=53.00, z=-2694.50], EntityCreeper['Creeper'/616150, l='MpServer', x=104.50, y=53.00, z=-2695.50], EntityZombie['Zombie'/616151, l='MpServer', x=106.50, y=53.00, z=-2695.50], EntitySkeleton['Skeleton'/616242, l='MpServer', x=105.50, y=41.00, z=-2698.50], EntitySkeleton['Skeleton'/616241, l='MpServer', x=108.50, y=41.00, z=-2701.50], EntityCreeper['Creeper'/616250, l='MpServer', x=123.50, y=16.00, z=-2563.00], EntityCreeper['Creeper'/616249, l='MpServer', x=122.31, y=16.00, z=-2562.69], EntitySkeleton['Skeleton'/616255, l='MpServer', x=90.50, y=23.00, z=-2572.50], EntitySkeleton['Skeleton'/616252, l='MpServer', x=73.50, y=22.00, z=-2706.50], EntityItem['item.tile.rail'/624674, l='MpServer', x=82.72, y=17.13, z=-2618.87], EntityItem['item.tile.rail'/624677, l='MpServer', x=63.94, y=17.13, z=-2598.36], EntityItem['item.tile.rail'/624687, l='MpServer', x=77.13, y=22.13, z=-2589.88], EntityItem['item.tile.rail'/624688, l='MpServer', x=88.22, y=22.13, z=-2588.53], EntitySkeleton['Skeleton'/616223, l='MpServer', x=121.50, y=34.00, z=-2695.50], EntityItem['item.tile.rail'/624709, l='MpServer', x=73.19, y=17.13, z=-2618.78], EntitySpider['Spider'/616290, l='MpServer', x=-4.68, y=20.68, z=-2566.28], EntitySkeleton['Skeleton'/616288, l='MpServer', x=-6.50, y=20.00, z=-2564.50], EntitySkeleton['Skeleton'/616289, l='MpServer', x=-4.53, y=20.00, z=-2564.34], EntityItem['item.tile.rail'/624716, l='MpServer', x=65.72, y=18.13, z=-2597.19], EntityItem['item.tile.gravel'/622793, l='MpServer', x=70.88, y=18.13, z=-2596.19], EntityZombie['Zombie'/616307, l='MpServer', x=60.50, y=32.00, z=-2707.50], EntityItem['item.tile.gravel'/622791, l='MpServer', x=72.78, y=18.13, z=-2596.56], EntitySkeleton['Skeleton'/616256, l='MpServer', x=88.50, y=23.00, z=-2572.50], EntityItem['item.tile.rail'/624739, l='MpServer', x=87.25, y=22.13, z=-2587.28], EntitySkeleton['Skeleton'/616257, l='MpServer', x=106.50, y=63.00, z=-2637.50], EntityItem['item.tile.rail'/624755, l='MpServer', x=89.09, y=22.13, z=-2589.28], EntitySkeleton['Skeleton'/616287, l='MpServer', x=-5.50, y=20.00, z=-2565.06], EntityItem['item.tile.rail'/624761, l='MpServer', x=107.31, y=12.13, z=-2586.84], EntityItem['item.tile.rail'/624785, l='MpServer', x=108.41, y=12.13, z=-2583.81], EntityItem['item.tile.gravel'/624884, l='MpServer', x=93.45, y=18.49, z=-2597.49], EntityItem['item.tile.rail'/624625, l='MpServer', x=63.94, y=17.13, z=-2598.31], EntityItem['item.tile.rail'/624565, l='MpServer', x=73.75, y=17.13, z=-2619.75], EntityClientPlayerMP['Player671'/602828, l='MpServer', x=50.00, y=83.52, z=-2627.69], EntityItem['item.tile.rail'/624514, l='MpServer', x=77.13, y=22.13, z=-2588.19], EntityFallingSand['Falling Block'/620932, l='MpServer', x=93.50, y=18.58, z=-2597.50], EntityFallingSand['Falling Block'/620933, l='MpServer', x=93.50, y=19.87, z=-2596.50], EntityCow['Cow'/614599, l='MpServer', x=78.50, y=67.00, z=-2617.50], EntityCow['Cow'/614598, l='MpServer', x=78.59, y=67.00, z=-2625.75], EntityCow['Cow'/614597, l='MpServer', x=68.56, y=68.00, z=-2618.34], EntityCow['Cow'/614596, l='MpServer', x=72.75, y=68.00, z=-2621.75], EntityMinecartChest['entity.MinecartChest.name'/614602, l='MpServer', x=86.50, y=22.50, z=-2548.50], EntityMinecartChest['entity.MinecartChest.name'/614601, l='MpServer', x=79.50, y=27.50, z=-2561.50], EntityMinecartChest['entity.MinecartChest.name'/614600, l='MpServer', x=85.50, y=18.50, z=-2582.50], EntityCow['Cow'/614588, l='MpServer', x=32.38, y=65.00, z=-2650.44], EntityCow['Cow'/614589, l='MpServer', x=45.13, y=63.00, z=-2646.22], EntityCow['Cow'/614590, l='MpServer', x=31.06, y=64.00, z=-2642.88], EntityCow['Cow'/614587, l='MpServer', x=38.19, y=64.00, z=-2650.13], EntityFallingSand['Falling Block'/624226, l='MpServer', x=93.50, y=19.97, z=-2596.50], EntityCow['Cow'/611007, l='MpServer', x=-13.50, y=67.00, z=-2632.50], EntityChicken['Chicken'/614900, l='MpServer', x=47.50, y=73.00, z=-2690.50], EntityMinecartChest['entity.MinecartChest.name'/614792, l='MpServer', x=95.50, y=17.50, z=-2554.50], EntityCow['Cow'/611008, l='MpServer', x=-14.47, y=66.00, z=-2634.50], EntityCow['Cow'/611009, l='MpServer', x=-12.94, y=67.00, z=-2634.50], EntityCow['Cow'/611010, l='MpServer', x=-15.88, y=65.00, z=-2634.50], EntityPig['Pig'/611062, l='MpServer', x=62.50, y=83.00, z=-2548.50], EntityPig['Pig'/611061, l='MpServer', x=60.50, y=81.00, z=-2549.50], EntityMinecartChest['entity.MinecartChest.name'/611059, l='MpServer', x=57.50, y=14.50, z=-2553.50], EntityMinecartChest['entity.MinecartChest.name'/611058, l='MpServer', x=64.50, y=13.50, z=-2582.50], EntityCow['Cow'/611057, l='MpServer', x=69.50, y=63.00, z=-2596.50], EntityCow['Cow'/611056, l='MpServer', x=68.50, y=63.00, z=-2598.50], EntityPig['Pig'/611064, l='MpServer', x=59.50, y=79.00, z=-2548.50], EntityCow['Cow'/611054, l='MpServer', x=56.44, y=64.00, z=-2605.25], EntityCow['Cow'/611055, l='MpServer', x=63.91, y=68.00, z=-2613.79], EntityCow['Cow'/611052, l='MpServer', x=54.90, y=64.00, z=-2608.52], EntityCow['Cow'/611053, l='MpServer', x=56.59, y=66.00, z=-2614.91], EntityCow['Cow'/610635, l='MpServer', x=-6.22, y=63.00, z=-2560.31], EntityCow['Cow'/610634, l='MpServer', x=-21.50, y=63.00, z=-2559.50], EntityMinecartChest['entity.MinecartChest.name'/610637, l='MpServer', x=26.50, y=24.50, z=-2564.50], EntityCow['Cow'/610636, l='MpServer', x=-4.41, y=66.00, z=-2568.31], EntityChicken['Chicken'/614922, l='MpServer', x=103.50, y=66.00, z=-2699.50], EntityChicken['Chicken'/614923, l='MpServer', x=100.50, y=68.00, z=-2700.50], EntityChicken['Chicken'/614920, l='MpServer', x=101.53, y=68.00, z=-2699.41], EntityChicken['Chicken'/614921, l='MpServer', x=103.50, y=66.00, z=-2698.50], EntityChicken['Chicken'/614926, l='MpServer', x=121.50, y=64.00, z=-2707.50], EntityChicken['Chicken'/614927, l='MpServer', x=128.59, y=64.00, z=-2698.31], EntityChicken['Chicken'/614924, l='MpServer', x=123.50, y=63.00, z=-2706.50], EntityChicken['Chicken'/614925, l='MpServer', x=121.50, y=64.00, z=-2704.50], EntityMinecartChest['entity.MinecartChest.name'/610646, l='MpServer', x=48.50, y=17.50, z=-2570.50], EntityChicken['Chicken'/614918, l='MpServer', x=83.50, y=74.00, z=-2698.50], EntityChicken['Chicken'/614919, l='MpServer', x=82.50, y=73.00, z=-2698.50], EntityChicken['Chicken'/614916, l='MpServer', x=87.50, y=74.00, z=-2696.50], EntityChicken['Chicken'/614917, l='MpServer', x=91.47, y=69.00, z=-2703.47], EntityCow['Cow'/610710, l='MpServer', x=20.72, y=63.00, z=-2597.19], EntityCow['Cow'/610709, l='MpServer', x=7.47, y=68.00, z=-2598.72], EntityCow['Cow'/610708, l='MpServer', x=22.09, y=63.00, z=-2598.16], EntityCow['Cow'/610707, l='MpServer', x=15.41, y=64.00, z=-2601.56], EntityItem['item.tile.gravel'/617394, l='MpServer', x=66.19, y=18.13, z=-2577.16], EntityFallingSand['Falling Block'/619043, l='MpServer', x=155.50, y=29.03, z=-2556.50]]
	Retry entities: 0 total; []
Stacktrace:
	at net.minecraft.src.WorldClient.addWorldInfoToCrashReport(WorldClient.java:405)
	at net.minecraft.client.Minecraft.addGraphicsAndWorldToCrashReport(Minecraft.java:2446)
	at net.minecraft.client.Minecraft.run(Minecraft.java:769)
	at java.lang.Thread.run(Thread.java:722)

-- System Details --
Details:
	Minecraft Version: 1.5.1
	Operating System: Windows 8 (amd64) version 6.2
	Java Version: 1.7.0_15, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 419186360 bytes (399 MB) / 1037959168 bytes (989 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 3 total; -Xincgc -Xms1024M -Xmx1024M
	AABB Pool Size: 17696 (990976 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	Suspicious classes: Start[net.minecraft.src.IPlayerUsage, MinecraftError, ReportedException, ...]
	IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
	LWJGL: 2.4.2
	OpenGL: AMD Radeon HD 7600M Series GL version 4.2.12172 Compatibility Profile Context 12.100.17.0, ATI Technologies Inc.
	Is Modded: Very likely; Jar signature invalidated
	Type: Client (map_client.txt)
	Texture Pack: cjb.zip
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 3039 (170184 bytes; 0 MB) allocated, 14 (784 bytes; 0 MB) used