Binary workbook .xlsb data import issue

Hey guys,

here's the situation:
I got one .xlsx file in which is basically filled with links to 4 other workbooks. As updating/importing data from all workbooks, each having about 200 000 cells (about a 800k total) took forever, I looked for options to speed up this process. Even though there does not seem to be a way to increase calculation speed of the imported Data (except new hardware), changing the source file Formats from .xlsx to .xlsb should appareanlty speed up data import (as read-speed supossedly is about twice the speed of .xlsx).
Now that I tried that though, updating/importing data from the 4 source-workbooks (now .xlsb) appears to not work properly anymore. I can update individual cells (by "editing" the link) in my target-workbook (still .xlsx) but when I try to update all the data from one or several workbooks at once (through the according menu) just about nothing happens. The source files are not opened when I tried this and I really can't do that to import the data as excel crashes everytime I try to open one of the source workbooks simultaneously with the target workbook. Also, excel states the status of the source-workbooks is "ok", which in my understanding means that its up to date.
Am I missing something here or is it simply impossible to import data from .xlsb files without opening them?

Thanks alot in advance!
Greetings
Hell

you can speed things up in a xlsx if you turn off screen updating and turn calculation mode to manual until the end when you calculate the book by turning autocalc back on

sorry i don't have much experience with xlsb files, but they should work the same

I didn't think of turning screen updating off, thanks for that!
I am however not running any macro in that workbook, so if I disable screen updating through a VBA-Code, would it apply even though no macro is actually running? My VBA skills are rather rudimentary, so meh^^

Other then that, I hope someone could still help me out with my binary file issue. Its rather annoying <.<