I'll try and be brief: I've just swapped my Asus Radeon HD4670 512Mb for a VTX HD6670 2Gb, to use on my Windows 8 PC.  Reason was basically to avoid having a legacy card, so I'd still get updates and programs like Firefox wouldn't have the card on their blacklist etc.

Anyway, after I put the new card in, Windows wanted to re-run the Experience Index, and to my surprise, Desktop Graphics dropped from 6.7 (which it was with the 4670) to 5.9, and 3D Graphics dropped from 6.7 to 6.6.  I could stomach the same score, given that it's really a more recent version of the same card, but not one much lower.

The 4670 had been using the Windows 8 legacy driver (12.6), and I tried both 12.10 and now 12.11 b7 with the 6670, but no change.  I've tried Novabench as well, and the score for graphics comes out lower with the 6670.

I've had the 4670 back in and retried, and it still scores better.  I've sort of assumed it's a driver issue, so I've uninstalled everything AMD (ran its uninstaller from Add/Remove, choosing Express Uninstall of all AMD software), followed that up by removing anything AMD/ATI related using CCleaner and Driver Sweep, and reinstalling from scratch.  Same result every time.

So I'd say that there are 3 possibilities:

1. The 6670 is not as good as the 4670 (seems unlikely - I'd expect at least the same performance)

2. The Catalyst driver for Windows 8 / Radeon HD 5/6/7/8000 doesn't work properly for the 6670 (likely)

3. Something I don't know about (also likely).

Anyone out there suggest anything?  Does it seem like drivers to you? If I run the 6670 with legacy driver 12.6 I still get the same by the way.

PC mobo is ASUS M4A785TD-EVO, Phenom II X4 810 2.4Ghz, 8Gb DDR3, Win 8 Pro 64-Bit, 450w FSP Group power, no overclocking or messing around of that nature.

Thanks in advance...

Try going to the AMD VISION control center > Gaming> 3d App settings > Use AMD pre-defined and choose which program/game to use on>Apply

Wait what? Is this yet another thread about that damn WEI? Ignore it and get on with your life, Jesus...

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Crosshair IV Formula, Phenom II x4 965 w/ Corsair H60, 8 GiB OCZ Platinum DDR3 1600, XFX HD 7970 Ghz, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, HP ZR2440w, Win 7 Ultimate x64

If it were only WEI maybe that would be fair enough, but I also said that Novabench gave a lower score for graphics and for FPS, which is why I think something's up.

How about actually playing a game and seeing if there are any differences, which there will be since Windows 8 hasn't been out a month?

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Crosshair IV Formula, Phenom II x4 965 w/ Corsair H60, 8 GiB OCZ Platinum DDR3 1600, XFX HD 7970 Ghz, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, HP ZR2440w, Win 7 Ultimate x64

Well I managed to acquire an Asus 6670 to use for comparison purposes.  And guess what: WEI is back up to 6.7 for both graphic types, and a Novabench test ranks its performance above both the 4670 and the VTX 6670, same 12.11 b7 driver.

So the VTX is going back.