I've just set up my mackintosh after following the optimus enabled guide here:
https://osxlatitude.com/index.php?/topic/7268-dell-latitude-e6430e6530-with-optimus-enabled/
I'm currently running 10.9.5, A13 bios, optimus enabled. When I scroll in apps like Skype or sometimes browser the screen seems to flash a lot.
On first boot as well, as soon as it powers up in immediately goes into sleep mode and then works fine once it's powered up after that.
Multitouch on the trackpad also isn't great but I can live with it...
Any ideas? Should I reinstall without optimus?