I am trying to store data which comes from the output of an entity "A" 
(std_logic_vecotr(7 downto 0 bits). Per data transmission the entity "A" 
updates it output and may recieve max 64 bytes and store them in Entity 
"B" for further processing.

I store the data through a variable std_logic_vector (511 downto 0)   in 
Entity "B" and then I parse the recieved buffer to an Entity "C". Is it 
ok if I pass the parsed data to an Entity "C" with an output of lets say 
std_logic_vector(239 downto 0) or is it better if I just have an output 
with a std_logic_vector(7 downto 0) and send the required data per clock 
cycle and store it inside a variable?

This is repeated between other entities I have so I dont know if its 
better to pass all the bytes directly between outputs or have a 1 byte 
buffer output that is updated between clock cycles.

Im not an expert on vhdl so Idk if when I synthesize the code it would 
be better to use a 1 byte buffer output or send all the data (1-64 
bytes) between entitites.

Best regards