Driver software to be tweaked to reduce Radeon frame latencies in series of updates
To our surprise, we recently found that the GeForce GTX 660 Ti generally outperforms the Radeon HD 7950 in our latency-focused tests in many of the latest games, despite the fact that the Radeon is based on decidedly beefier hardware. Although the Radeon cranked out conventionally respectable FPS averages, it often produced a number of long-latency frames interspersed throughout our testing sessions. Follow-up testing confirmed the problem isn't confined to Windows 8, and we even posted a slow-motion video illustrating the issue. We concluded that AMD has work to do in optimizing its drivers for the latest games.
Earlier today, in my blog post, I noted that AMD's David Baumann had posted in a thread at Beyond3D, stating that a host of different software-related issues are potentially responsible for the Radeon's latency issues. He claimed the slowdowns in Borderlands 2 are a buffer-sizing issue that could be addressed via a Catalyst Application Profile (CAP) update.
After seeing my blog post, Baumann contacted us to provide some additional insight into the situation, including word of a series of driver updates in the works intended to smooth out frame latencies. He writes:
The comment that you quote was just one update that highlights that some things can be tweaked fairly easily (although since coming back today I learn that it is not quite as easy as the BL2 fix does actually need to be implemented in the driver so we will have to QA a new build rather than releasing a CAP). Over the early part of the year you'll see a few driver updates help this across a variety of games.
We're pleased to see that AMD will be addressing these issues soon, even if Borderlands 2 can't be patched via a CAP update.
The most intriguing revelation in Baumann's correspondence, though, concerns one specific technical contributor to the frame latency problems on HD 7000-series Radeons based on the GCN architecture: less-than-optimal memory management in software.
Additionally, when we switched from the old VLIW architecture to the GCN core there was a significant updates to all parts of the driver was needed – although not really spoken about the entire memory management on GCN is different to prior GPU's and the initial software management for that was primarily driven by schedule and in the meantime we've been rewriting it again and we have discovered that the new version has also improved frame latency in a number of cases so we are accelerating the QA and implementation of that.
So a specific portion of AMD's driver code needs some additional attention in order to perform optimally on the year-old GCN architecture—and AMD has accelerated an overhaul of it after discovering that the new revision can alleviate frame latency issues. Wow.
Although we're not happy about the situation facing current Radeon owners, we're gratified to see that AMD has taken notice of the problems and is working to resolve them. We're also thrilled by the possibility that our latency-focused game testing may have helped nudge one of the major GPU makers into making changes that could result in improved gameplay fluidity for PC gamers going forward. Stay tuned to TR for additional updates on this situation as they become available.