There are two types of ShaderBlocks that can be used: uniform and compute.

Uniform blocks are read only in shaders, can sometimes be a bit faster than compute blocks, and have a limited size (but the limit will be at least 16KB, you can check to check).

Compute blocks can be written to by compute shaders, might be slightly slower than uniform blocks, and have a much, much larger maximum size.

uniformA uniform block.
computeA compute block.

See also