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My steps for HD 7750 + 8670D hybrid crossfire


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I know some people have had some trouble getting hybrid crossfire in this and similar weird unofficial configurations to work... myself included!  I want to share my steps that have led to it enabling itself while they're fresh in my mind.  Many of these might be totally irrelevant, in fact hopefully most of them are, but this is still black magic so anything that could possibly have affected it is included.

Hardware is A10-6800K, Asrock FM2A88M Extreme4+ and Sapphire Ultimate passive 7750.  Monitor is some BenQ thing connected with a passive HDMI to DVI adapter cable (HDMI on the system, DVI on the monitor).  If any hardware other than that affects it, I'm quitting OC.

  1. Set system up with iGPU, no 7750
  2. Configure bios with PCIe graphics as default but iGPU explicitly enabled, share memory set to 2GB
  3. Make fresh install of Windows 7 64-bit SP1, using a flash drive that was created with the asrock USB driver injection tool for AM4
  4. Install Catalyst Omega 14.12 (downloaded from guru3d, filename "[Guru3D]-amd-catalyst-omega-14.12-with-dotnet45-win7-64bit.exe").  Custom install was chosen and everything but the driver, CCC and mandatory components (I think only the install manager was mandatory) was unchecked.
  5. Install 3DMark06, CPU-Z 1.90.1 and GPU-Z 2.27.0
  6. Run 3DMark06 4 times testing different memory settings
  7. Notice a weird drop in CPU score, install furmark and copy portable prime95 and hwinfo64 onto system to check if there's power/thermal throttling
  8. Try to start hwinfo64, it complains it needs KB3033929 for driver signing, install KB3033929.
  9. Spend 2 hours banging your head against the wall trying to figure out why CPU score keeps getting worse (THIS STEP IS MANDATORY)
  10. Set up k15tk (it needs winring0 dlls so I unzip throttlestop 8.70.6 then move the k15tk exe into the throttlestop folder), try to use that to force max pstate
  11. Realise that asrock boards need turbo core enabled and no it won't interfere with your oc, re-enable turbo core
  12. Do a couple more 3DMark06 runs
  13. Set memory back to stock, power off system
  14. Install 7750, move HDMI cable from motherboard output to 7750
  15. Power system on.  Open the detailed 'found new hardware' information, wait patiently for it to all run and finish.
  16. Reboot, wait patiently again
  17. CCC pops up after a minute or two with dual graphics configuration

Hopefully this helps.  I imagine it can probably be boiled down to:

  1. Install OS and drivers on iGPU
  2. Spend 2 hours banging your head against the wall trying to figure out why CPU score keeps getting worse
  3. Install 7750
  4. Let windows auto-install 7750 drivers, be patient

It's also worth highlighting that nowhere in this steps is any OS stripping/optimisation.  That comes later...

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On a different board (Asus F2A85-V PRO, thanks for asking) I followed the basic steps of "Install OS and drivers on iGPU, install 7750, receive bacon" to no avail.  Being an impatient sod who was getting deeply frustrated I changed multiple things at once, but worked was one or both of;

  • Semi-blindly deleting all the registry keys for some "standard VGA graphics adapter" devices
  • Installing the 7750 while an overclock was applied on the iGPU (in addition to having iGPU multi-monitor enabled and the iGPU forced on in bios)

Checking back my notes I believe that previously when I was testing with this asus board and added the 7750, the iGPU was probably overclocked.  I guess it might force it to be enabled or something?

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