Marlin RC6 with graphic LCD causes short pauses while printing

Hello to all!
I'm new on this forum, since i just recently bought my Kossel Mini delta printer. It had Marlin V1.0.0 with 4x20 LCD, so i bought Full graphic smart controller and loaded RC6 firmware. All works fine, except i can see small pauses in printing each time arduino is updating GLCD - pause is pretty short - say, 0.1s or something like that. Is this normal? That didn't happen with 4x20 LCD. I guess it takes more time to write on GLCD...
I just want to be sure that my configuration is OK. This pauses happen at equal intervals and exactly when X,Y and Z is updated, and it doesn't occur when i send command "home".

Should i change anything to make it stop?

Thanks!

Best regards from Paul, Slovenia

EDIT: i guess that i should made my homework better before buying...it seems that delta and mega2560 are not the best combo, am i right? It seems that only way is going back to 4x20 LCD or change electronics to ARM...