[O] setting priority through S-down and S-up is laggy on i5 cpu

[Michael Ziems]

Hello,

i got two windows machines: one is a surface with an i5 cpu and a 
desktop machine with an amd 6 core cpu.

on both machines i have org mode 8.2.10.

when i switch the prioity in an 15k line org file having 614kbyte in 
size on the i5 machine the system is really laggy and it takes up to two 
seconds changing the priority of todo headlines. on the desktop machine 
with a similar powerful cpu one a core level the changing is lightning 
fast. recently i got get the i5 machine also that fast by just adding 
the file again to the agenda list, but after restarting emacs it was 
slow again and now i cannot reproduce the same.

does anyone have an idea what could be the reason here?

thanks in advance.

Michael