isacumi!
Have you checked what version monitor you have? if it`s 00 you can replace it with 01 that will probably fix the sleepmode bug.
when your monitor goes to sleep mode after the driver install, have you checked that it just don`t svitch the output to hdmi ? it does that sometimes when I install new drivers.
I must say that the 3910 driver works great, there are a few bugs, like windows 8.1 controlpanel wrongly show 30hz, but it is definitely 60hz like the Intel controlpanel says.
and the sleepmode problem, but`s thats the bug in my rev 00 monitor