Texture pack sizes

[Bestduck]

Making a texture pack which is mostly 16x16, but I would like a slightly bigger size for the sword. 32x32 seems too big for my sword, and I found this post saying non 2^x sizes will be laggy:Reddit post
I’d like to use ~22x22, but that change by a few
1. How laggy will it be if I just use a few non 2^x sizes?
2. Are some sizes less laggy than others, for example would 24x24 run better than 21x21, since 24x24 is “closer” to a power of 2?

 

[min_bal]

I doubt that it makes any (noticable) difference
given that minecraft the game is just a bunch of 16x16x16 cubes
i do not think the gpu will have problems with performance
what minecraft version will the pack be for?
do you mean the item texture in the inventory or the item model when you hold it?

 

[7xr]

From what I know and personal experience, non 16,32,64 etc. packs do not make the game much laggier, but will look blurry if you don't have mipmap levels set to nearest/off

1. I've used 20x20 packs and they don't make a noticeable difference performance wise
2. I don't think it makes a difference

It's all to do with how binary numbers work in hardware

Eg.
To double a binary number you move bits to the left
00000001 = 1
00000010 = 2
00000100 = 4

This is significantly faster than actually working out what 2*2 is in long form because you can literally just flip some switches in memory.
That's the speed bit (obviously there's more to it)

The main thing in terms of graphics is that there's a bunch of GPU stuff that relies on dividing a texture in half over and over again or works on 2*2 groups of pixels (mipping, filtering, compression, sampling etc).
If you have a power of 2 you can guarantee that those operations will work, if not you absolutely cant