Infama, my understanding is that the firmware you provided a link for is for TomTom WORK and, unfortunately, I saw one poster who installed said it had NOT cured either the stuttering or the map lag.
Do you have a different experience, especially since the firmware has NOT been officially released by TT?
I have not used it.
I got it from PGPSW and the poster there said it cured his 720 stutter.