These instructions are as good as it gets, windows 10 has somewhat tighter driver security then windows 7 or 8 (or 8.1), read through these instructions carefully, take your time, if you still can't get it, tell me
what specific step your stuck on:
For starters, go to nvidias' site and download the official windows 10 64 bit 355.82 driver installer here ->
http://www.geforce.com/drivers
install these drivers normally.
Then follow these instructions carefully and 1 step at a time:
So, the process is as follows for us Windows 10 users.
1. Install drivers from Nividia
2. Check for Windows Updates. Let Windows download 355.82 display driver form Nvidia
3. Restart your computer (Usually windows will prompt you to restart upon installing this driver)
4. Download DifferentSLIAuto (1.3.1 as of today) and then extract it wherever:
https://github.com/EmberVulpix/DifferentSLIAuto/releases
5. Download Jbailey8's 355.82 patched Nvidia driver:
http://www.gamefront.com/files/25201868/nvlddmkm2-35582-win10-64bit.rar
6. Put the patched Nvidia driver into your DifferentSLIAuto folder.
7. Locate the Install.cmd file, then right click it and run it as administrator
Once it's finished, it should look like this:
http://i.imgur.com/u5KDvSC.png
However, sometimes it's not able to copy the driver into your system, resulting in this:
http://i.imgur.com/2D5l09x.png (0 files copied)
If it did not copy the driver over, move to the next step. If it did, move to step 10
8. Navigate to C:\Windows\System32\drivers and locate the file named nvlddmkm.sys
9. Rename this file, doesn't mater what you rename it. But keep in mind, you can use it as a backup. I renamed mine nvlddmkmBACKUP.sys
9. Copy the nvlddmkm.sys patched driver in your DifferentSLIAuto folder to the same folder where you renamed nvlddmkm.sys
10. This part is a little tricky. Click Restart while holding shift until you see "Please Wait". You'll get an advanced menu.
a. Click on Troubleshoot
b. Advanced Options
c. Startup Settings
d. Then click Restart
This guide may help and the process is the same for Windows 10:
http://www.howtogeek.com/126016/three-ways-to-access-the-windows-8-boot-options-menu/
11. When shown the advanced startup menu, press number 7 on your keyboard. (NOT F7, which doesn't seem to work for me)
12. Windows will start with Driver Signature Enforcement disabled. (You must repeat step 10, every time you boot windows, otherwise windows will NOT load the patched driver. Even with Test Mode on)
13. Right click on your desktop and click on NIVIDIA Control Panel, then check to see if you can enable SLI and then enable it, of course. (Not all motherboards will work with this, it's a hit or miss)
14. Verify it's working. In the Nvidia Control Panel, click 3D Settings (NOT Manage 3D Settings) at the top, next to Help and Desktop and click Show SLI Visual Indicator.
15. Run a SLI compatible game of your choice. You should see a bar on the left side of your screen. The greener the bar, the better SLI is performing. Do these same steps to disable it.
If you need help on a specific step, let me know.