reprap full graphic controller flickers/ lags when in SD menu

I've just "upgraded" my prusa i3 clone from a reprap smart controller to a reprap full graphic smart controller.
It seems to work ok (after I've reversed the ribbon cables) but when i select the "print from SD" menu on the lcd it flickers and lags when I scrolls through the print files on the SD. what can be the problem(s)? and how can i (hopefully) fix it?

- the resaon why I've "upgraded" to a full graphic controller is (obviously) that I want to change bootscreens etc...

PS. I'm using a MKS Gen board

You might need to map/test each pin in the ribbon connectors.

It might seem like it has been enough to "reverse the ribbon cables", but some pins within the ribbon cable sockets may actually be different than than your "old" LCD.

Not all clone manufactures follow the ReprapDiscount standard pin placement exactly in the ribbon cable. And you needing to reverse the cable, seems to indicate that they, for some odd reason, has made some "clever" changes. And now you need to discover what changes they might have made.

Do you have many files on the SD-card?

Does your computer create folders starting with "."?
If so, remove those folders.


How much RAM is left when you have compiled your new firmware?
The full graphic LCD might use more RAM than the text only LCD. Or you might have compiled new features into your firmware, and this uses more RAM than your previous setup.
RAM is a very precious commodity on those ATmega chips.

if is this what you're asking?

"Sketch uses 116984 bytes (46%) of program storage space. Maximum is 253952 bytes.
Global variables use 4575 bytes (55%) of dynamic memory, leaving 3617 bytes for local variables. Maximum is 8192 bytes."

Quote
MrAlvin
You might need to map/test each pin in the ribbon connectors.

It might seem like it has been enough to "reverse the ribbon cables", but some pins within the ribbon cable sockets may actually be different than than your "old" LCD.

Not all clone manufactures follow the ReprapDiscount standard pin placement exactly in the ribbon cable. And you needing to reverse the cable, seems to indicate that they, for some odd reason, has made some "clever" changes. And now you need to discover what changes they might have made.

is there a guide to how that's done somewhere? (I'm pretty new to programming soI'm not quite sure what to look for...)

... and thanks for your replies, really appreciate it!