FPS low when I turn on M18x, fine after restart

When I turn on the M18x and load up a game, fps is really low until I restart the machine. I don't know what is causing this. Seems to be fine on 1 GPU but not on SLI - 1 GPU is near 100% usage and the other about 20%.

Things I have tried:

Original OS (Windows 7) - I'm no on Windows 10
Different GPU drivers
Blown any dust off SLI connectors
Reflash BIOS
Reflash VBIOS's - they are on stock clock speeds
Switched to Integated Graphics (HD 3000) then back to GPU's (2 GTX 580M's)
Unplugged everything
Holding the alt key when I turn the machine on and run the Hardware Assessment, to which it passed.

Heat is not the issue as I've only just turned the system on. Also I can play hours on end with no fps drop.

I used Call of Duty Black Ops main menu for my test. I should get 40fps in the menu but I get between 6 and 14 fps. After restart, I'm back to 40 fps.


Almost sounds like your machine thinks it's running off the battery instead of the power brick. It's a bit hard to work it out without the machine in front of me. Sounds like you've tried just about everything. Have you tried changing your power settings or doing a battery drain? Simple things I guess but you never know.
Just pulled off the battery and left the machine off for a while, turned it on and I've got low fps again! Seems like something is not right when the machine starts up but is fine upon a restart?

This started a few months ago when I was on Windows 8.1 connected up to an external TV and Surround Sound System via HDMI. Since then, I got a desk so I'm not connected up to any external devices, I'm on a fresh install of Windows 10, partitioned my drive and put Windows 7 on it, to which all have the problem.

I shall do a static discharge on the laptop and power supply whilst the battery is off now and I will report back later if it worked or not.

Many thanks for your help, it is much appreciated!
Okay so I set forced the game to load without SLI and FPS is much higher than it is with it on! I mean the difference here is with it off I hit 60fps but with it on I get about 14fps... GPU1 at 20% utilization and GPU2 at 90% utilization. Could this be an issue with SLI not being initialized properly on boot or a GPU slowly dying?
Sorted it! I took the whole laptop apart including the CPU and GPU's, blowed out any dust, cleaned off SLI connectors and put it all back together. Works perfectly now!
DUST is a huge killer! but once you fix dust:

priority of performance enhancements (where you ought to spend $ from top to bottom):
1. SSD
2. GPU
3. RAM
4. CPU