"Unable to fit" error in MC1.8 for much smaller texture packs than ones that worked for MC1.7

What I expected to happen was that only a little bigger texture packs wouldn't want to lad on MC1.8. However I can load 512x texture packs in MC1.7 while some 128x texture packs throw "Unable to fit texture" error.

Every time a texture pack loaded grows above around 400-500 MB I get the "Unable to fit texture" error and Minecraft stops from loading it. While running minecraft 1.7 jar same texture packs or even x4 or even x8 times bigger ones load without any problem taking up to 2.5 GB. I have been through all the steps related with this error and manually set Java memory to 8GB and when I press F3 in-game I can see this works. However still texture packs don't load. I would have expected an update to minecraft to allow for better performance/quality, however while FPS is twice as good the top quality that can be sqeezed out of MC is 1/4 or even 1/8 of what it was in MC1.7. That is hardly an improvement. - it is not simply a slight increase in RAM usage due to massive rendering changes, as many people seem to assume. It is especially unsettling that mine is a rather powerful machine (with 16GB RAM to spare and 1GB AMD RADEON HD 6770).

• However I did notice that mostly only icons (textures in the "items" folder) cause the majority of the problems so I think it would be good to look into item icon rendering or preloading methods. I've even tried merging a Hi-res pack with a Low-res pack using the "items" folder from the Low-res pack and the rest from a Hi-res pack and it all seems to fit and launch although everything together takes up more than 1GB of RAM.

• It is worth mentioning that I thoroughly examined the situation with the help of one of the on-line chat voulunteers. The problems are not Java-Related. The exact same problem occurs only with MC1.8 with all versions of Java (8, 7 and 6).

• Error report:

  ---- Minecraft Crash Report ----
  // Would you like a cupcake?
  
  Time: 11/3/14 7:34 PM
  Description: Initializing game
  
  ctz: Unable to fit: minecraft:items/wood_shovel - size: 128x128 - Maybe try a lowerresolution resourcepack?
  	at ctw.c(SourceFile:60)
  	at cua.b(SourceFile:197)
  	at cua.a(SourceFile:77)
  	at cxh.j(SourceFile:553)
  	at cxh.a(SourceFile:139)
  	at cxk.a(SourceFile:23)
  	at cvt.a(SourceFile:99)
  	at bsu.aj(SourceFile:437)
  	at bsu.a(SourceFile:299)
  	at net.minecraft.client.main.Main.main(SourceFile:120)
  
  
  A detailed walkthrough of the error, its code path and all known details is as follows:
  ---------------------------------------------------------------------------------------
  
  -- Head --
  Stacktrace:
  	at ctw.c(SourceFile:60)
  	at cua.b(SourceFile:197)
  	at cua.a(SourceFile:77)
  	at cxh.j(SourceFile:553)
  	at cxh.a(SourceFile:139)
  	at cxk.a(SourceFile:23)
  	at cvt.a(SourceFile:99)
  	at bsu.aj(SourceFile:437)
  
  -- Initialization --
  Details:
  Stacktrace:
  	at bsu.a(SourceFile:299)
  	at net.minecraft.client.main.Main.main(SourceFile:120)
  
  -- System Details --
  Details:
  	Minecraft Version: 1.8
  	Operating System: Mac OS X (x86_64) version 10.10
  	Java Version: 1.8.0_25, Oracle Corporation
  	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
  	Memory: 500213504 bytes (477 MB) / 943718400 bytes (900 MB) up to 7635730432 bytes (7282 MB)
  	JVM Flags: 1 total; -Xmx8G
  	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
  	Launched Version: 1.8
  	LWJGL: 2.9.2
  	OpenGL: AMD Radeon HD 6770M OpenGL Engine GL version 2.1 ATI-1.28.29, ATI Technologies Inc.
  	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.
  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: [Aryam's POWER PACK]
  	Current Language: English (US)
  	Profiler Position: N/A (disabled)
  

  Steps to Reproduce:
  1. Put a small (16x or 32x) custom texture pack in .minecraft folder.
  2. Launch minecraft then choose the resource pack in the resource pack menu, and click Done.
  3. Close minecraft.
  4. Replace (Trying to choose a large pack from the beginning will simply result in the game returning to the Default pack without any feedback or error reports, thus the replacement needed.) the Texture Pack with a large one enough to throw an "Unable to fit" error, in the .minecraft folder (mind that it should have the same name as the replaced one). You should make sure that the "items" folder takes up at least 15 MB (14MB is a clear cap in my case [one more x256 texture results in crash, while replacing it with a x128 version and moving below the 14MB threshold makes the game launch smoothly]).
  5. Launch Minecraft with a profile using the MC1.8 version of the game. The crash should occur shortly after the Mojang logo appears.
  6. You can launch Minecraft with a profile using the MC1.7 version of the game (with the same texture pack) to see it will most likely start up correctly (unless the pack's size is drastically higher than available resources).