Here is the pic: http://imgur.com/a/cuxlr

And where do you find the "S3 Video Repost" option in CVFZ?

I tried changing those settings in the bios to no effect. Both in Win 10 and Pro. Still get the BSoD (atikmpag.sys)

Though I have to note that in Win 10 (not Pro) it was able to update the driver for the 5th gpu without touching the bios. It went to BSoD (atikmpag.sys) when trying to install the 6th. Where as in Pro I didn't even get past the 5th before reaching BSoD (atikmpag.sys). So I guess that's progress. When should I use 6xGPU_mod, after installing Win 10 with one gpu plugged in and not updated the driver?

Update 10/28/16: I have now been able to boot into windows 10 with all 3 gpus using crimson 15.12. But the 3rd 295 is not recognized. And after a few min of being connected to the internet I get BSoD, lol. Oddly enough if I disconnect from the internet its all good. I'll try and upload an image of what 6xGPU_mod wrote later today (I did not apply its settings yet cause I wanted your feedback of it).

Wholly smokes... 4 295X2s? Wowzers! Looks awesome

Thank you for your assistance. I will try changing the BIOS settings you have suggested on my CVFZ with this version of Win 10 before trying on a regular Win 10.

This is what mine looks like. The case is Lian Li's DK-01 Desk/Computer: http://tinypic.com/r/2ztldzr/9
Don't mind the cable management, lol. I'm ordering custom cables from ensourced.net so it will look all neat and tidy.

I have read through the entire thread confirming that this mod works with 6 R9 290s as well as in windows 10. I have a Crosshair V Formula-Z and 3 R9 295X2s on Windows 10 Pro. I know its basically 6 R9 290s. But just wanted to confirm if anyone is able to get 3 of these working.

So far...

1. Plugin one 295X2 closest to the CPU.
2. Disconnect Ethernet cable.
3. Install Windows 10 Pro.
4. Check Device Manager and see that Microsoft Display Driver is installed for both GPUs.
4. Shutdown.
5. Plugin two more 295X2s.
6. Boot.
7. Check Device Manager and see that Microsoft Display Driver is installed on one more GPU. But now two of the GPUs have a yellow triangle exclamation mark (error code 31). The other three are labeled "Video Controller" each with a yellow triangle exclamation mark (also error code 31).
8. Right-click on 6XGPU_mod and run as an administrator.
9. Select Force, Modify Registry, and Reboot, options. Then ran.
10. When finished Reboot.
11. Nothing has changed. See Step 7.
12. Manually update driver (latest Crimson) on the GPU without the exclamation mark. But it applied the driver to all three "Microsoft Display Drivers" replacing it with "Radeon R9 200 series" and are in good working order.
13. I proceed to manually update driver (latest Crimson) of one of the "Video Controller" with yellow triangle exclamation mark replacing it with "Radeon R9 200 series" and is in good working order.
14. I proceed to manually update driver (latest Crimson) of one of the remaining two "Video Controller" with yellow triangle exclamation marks. Computer reboots and I get BSoD: SYSTEM_SERVICE_EXCEPTION (atikmpag.sys)

I have tried this twice already. 1st time I forgot to clear the CMOS before plugging in the remaining two 295X2s. 2nd time I cleared the CMOS before installing the remaining two 295X2s. Both ending with the same result, Step 14. I will be trying Crimson 15.12 next. (Did they rename Catalyst 15.12 to Crimson 15.12?)

I have also tried installing Windows 10 Pro with all 3 from the get go but it doesn't pass the loading initialization screen. Only until I unplug one of the 295X2s does it proceed past it.

I have also tested each individually to make sure they meet the reference model standard. All three do.