Laptop GPUs (dedicated and integrated) are driving me crazy ever since I got this computer. I've searched thousands of forums and potential solutions and I couldn't find anything that solves my problem.
Main problem I guess is the dedicated GPU (GeForce 840M) which I swear has an attitude of its own! It sometimes runs a game on 40fps or more but sometimes 20fps or less for the same one I played an hour before with no problem! The problem timeline goes something like this:
1. Start playing/using with AC plugged and no battery (I noticed that without the battery it runs much better). Game runs smoothly.
2. I connect the battery and start using it for other things, unplugged.
3. Connect it to AC (sometimes just 5mins later) and the GPUs performance is just awful. Just to test it I overloaded it as much as I can but no sign came neither from temperature increase (around 57c max) or Clockage.
4. I use GPU-z and can notice large drops in GPU Core Clock (when im using the game) and smaller drops in Voltage. Temperature is not an issue, 65c-68c when working fine (as in no problems with gpu) but when the problem appears it doesn't go over 55c.
Main problem is that if I shut it down and start it without battery, it sometimes may again struggle (hence the attitude problem). When I hear the fan kicking in and it starts to make noise I feel relieved.
I've tried allot of solutions - power options, switchable graphics settings, driver reinstallation (clean), driver roll back, etc.
PS - I've noticed an annoying thing regarding battery and AC performance, as soon as I unplug the AC the screen dims a bit, but my power setting is always set to maximum performance.