R1 Switching Discrete on/off - does not turn off discrete..

I found a thread about this awhile ago (cannot find it now) and I seem to be suffering this issue. When the computer boots on the intel gfx it shows ~6 hours with a full battery. When I switch to discrete then back it drops to 2.5 hours. GPUz reports the nvidia graphics running at its default core/memory speed and windows device manager shows the nvidia gpu active and working.

When I first boot the computer with integrated intel active, the nvidia one does not show in device manager.

I've tested this with a newly unboxed m11x with same behavior.

edit: these are latest dell drivers.

edit: I have two brand new m11xs side by side. One has a 7200 rpm hard drive (momentus XT), AlienFX lights on, brightness of ~60% and I'm actively browsing internet with on wifi. The other one is completely stock, alienfx lights off, wifi off, dimmed all the way. Both show that they are running in "power saving" mode. The only difference is that the second one was switched on/off between discrete then back to integrated.

The battery level has only ticked away by 5% on the one I'm using in the time the other one with full power saving options has done 10%. Both on "Balanced" power mode.

So this is proof the battery tooltip in windows is not lying at that the discrete GPU is running in the background.

 

I just found this on the official forums stating the same thing back in April 2010
M11X - Issues Documented. PLEASE Update the BIOS! - Laptop General Hardware Forum - Laptop - Dell Community

Has there been an unofficial fix to this I'm unaware about? This was a huge selling point for this laptop for me and it's disheartening that I need to reboot to actually get the 6+ hours advertised battery life.

Edit: I've just discovered that if you switch back to integrated from discrete, go into sleep mode, upon waking the nvidia gpu is removed from device manager and battery life sky rockets. I suppose this is better than rebooting but would be better if it was more seamless.