I've been having problems with my Maxx lately. Its been much slower than usual and has been randomly freezing and won't turn on which only resolves after I do a simulated battery pull (hold down power button and volume down until it reboots).
One of the things I noticed was that my gallery was VERY slow to load pictures. So, I decided to do some troubleshooting...
Several months ago I purchased a SanDisk 32gb ULTRA micro SD. Some of the reviews were less than favorable stating that the transfer speeds were significantly less than the stated class 10. I was bored and decided to try another micro SD and got the one out of my Digital camera which is a Class VI samsung. Well, let me tell ya... its like having a new Maxx again.
Apps load faster now, music doesn't stutter and I can blow through all 1900 pictures in my gallery without having to wait for them to cue up. AND.... it hasn't locked up in several days.
So, from what I've read, Class 10 and Ultra cards can be a problem, not all Class 10's are truly class 10 and Class VI can be faster than class 10.
If your Razr/Maxx is running slow, before you give up on it, try a different Micro SD, especially a (less expensive) Class IV or VI.