Does this problem only affect Dual Graphics?
As far as we can tell, yes. We tested multiple games, including Skyrim, Orcs Must Die 2, Torchlight 2, Civilization V,and Metro: Last Light using only the integrated graphics aboard the APU. None of these games exhibited performance degradation of any kind whether Turbo Core was active or not. If anything, performance was slightly better with Turbo Core active, as you’d expect with higher clock speeds.
Discrete GPUs that don’t support Dual Graphics or aren’t rendering in that mode are not affected by this issue.
Why is Dual Graphics mode affected?
This is unclear and AMD is still working to understand the problem. Our theory — and it’s truly just a theory — is that the Advanced Power Management block’s clock speed adjustments throw off AMD’s frame pacing driver in some fashion. It’s not clear why this would be the case, but it might explain why some titles are affected and others aren’t. According to Anandtech, AMD’s frame pacing driver runs an adaptive algorithm that looks at a “window” of rendering times and uses this data to enforce a a minimum frame time, adjusting itself on the fly as necessary.
This kind of operation depends on low latencies — which means that clock speed changes caused by APM could be throwing off the driver. Hopefully we’ll know more soon.
>How widespread is the Dual Graphics problem?
Battlefield 4 is unaffected by the Dual Graphics bug
This is difficult to pin down. Games like Torchlight 2, Metro: Last Light, and Metro 2033, all of which are DX11 titles, are affected. Other games, like Skyrim and Orcs Must Die 2, aren’t. This seems to point to a link between the DirectX version and the game in question, which would make sense — AMD’s frame pacing driver is currently only compatible with DX10 and DX11 titles. But again, not every DX11 game is impacted – Battlefield 4 and Batman: Arkham City performed identically whether Turbo Core was enabled or not.
Right now, there are two ways to deal with the issue. First, you can download and install AMD Overdrive, and disable Turbo Core in software. Note that you’ll have to restart your system in order to bring Turbo Core back online.
The other method is to disable AMD’s Master APM and CPB Mode settings from within your motherboard’s UEFI / BIOS. This will run the CPU at a constant clock speed. We tested both methods and found them equally effective in terms of resolving the problem. Note that simply setting a manual CPU multiplier will not fix the problem — our A10-7850K at 4.2GHz would still pull down to 3GHz when the GPU was loaded.
How soon can we expect a fix?
We don’t have a clear timetable on that, but AMD has taken the issue extremely seriously. I’ve had multiple conversations with company staff and sent over a great deal of data detailing exactly how and when the bug occurs. AMD has been very responsive on this issue — it’s been taking driver updates extremely seriously over the last 12 months — and hopes to know more soon.
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