Debian Configuration :: Graphic Slow After Kernel Upgrade From 3.16 To 4.1

Intel Core i7-5500U with Intel HD Graphics.So I updated to the backports kernel and backports intel xorg drivers and I have the weirdest thing.Everything is stuttery even cinnamon desktop effects are no longer smooth. If I boot back to 3.16, everything is butter (except the screen corruption). Even my favorite wine game dropped 25% in fps.

I remember that on windows, if the cpu is too slow (pstate_min_speed), graphics is also stuttery. However, increasing /sys/devices/system/cpu /intel_ pstate/min_perf_pct even to 100% didn't do the trick. I suspect, that this measure is causing it: URL....

how to increase the performance again? I just found out, after running glxgears (with about 40 fps), that xrandr shows an available framerate of 40fps

xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 293mm x 165mm
1920x1080 60.00*+ 59.93 40.00

I guess that's what makes it feel slow. Do you know how to get that back up to 60 (fixed)? It seems like the screen refresh rate set in xrandr has no effect on the problem. When I boot, glxgears runs with 60 fps and everything is fine. After a while, it drops to 40 and the whole desktop keeps stuttering. if I change the resolution with xrandr and then change it back, it goes to 60 again for a while

LVDS_DOWNCLOCK is disabled
Code: Select allsystool -m i915 -av
Module = "i915"

  Attributes:
    coresize            = "1028096"
    initsize            = "0"
    initstate           = "live"
    refcnt              = "5"
    taint               = ""
    uevent              = <store method only>

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