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AMD to Tweak GCN Latency Issues with Driver Updates

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Driver software to be tweaked to reduce Radeon frame latencies in series of updates
by Scott Wasson — 2:56 PM on January 2, 2013
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.'


http://techreport.com/news/24136/dr...e-radeon-frame-latencies-in-series-of-updates

Thought I would put up a dedicated thread for discussion after reading matt's post on the BM thread.
 
Good to see AMD acknowledge the problem. I guess this is why some say Nvidia feels smoother even though AMD GPU's are giving more fps.

It's always nice to know when significant improvements are on the way :) It's especially nice to see a big company listening to the users (or at least tech sites).

Changed days for AMD, they are listening to feedback, which can only be a positive thing, provided they do the work needed in said titles.

Good work tommy.

I don't think we are going to see too many changes as from what ive seen it only affects a small number of titles.

Baumann himself said in a post afterwards

"You can also pick another set of titles and you may find very different results between the two companies as well.

You also have to question whether these things are going to affect you. I play a lot of Borderlands 2 (Lvl 50 baby!) on a 8 core Bulldover + Tahiti XT2 or a 4 core Phenom 2 and Picairn XT and can't say that I've ever noticed the effects of this in playing; the only thing that I did notice was the lag in displacement map loading, but that is common thing with UE titles."

Good on TechReport for raising the issue, but i do question some of their results based on what i found out myself by running a similar frame time benchmark.

I saw your results matt and took notice:).

TR, may/not have an agenda, but they did report last gen on the 56/70's having terrible frametimes while having faster fps, here's looking at you BF3(although it was a higher much more noticeable difference last gen in more titles), but, there was very little fanfare in comparison to this gens dedicated frametime article(considering the high/low number of fps in comparison to what Skyrim/BF3 can individually pump out)- whether that was to not fall out of bed and feel the wrath of Nvidia(it is that bad with Nvidia btw) or not can be left to the individual to decide.

I should throw in that the only 2 titles I have noticed any jitter was Skyrim in 3D(beta driver though) and FC3 until the caps came out, as the fps are so high@1080p in my setup, it's very hard to notice any jitters.



On the flip side of the coin, it is possible that AMD were well aware of the frametimes but pushed beyond what the driver could give for BM results in order to be the champs this gen, but I will stress that it doesn't happen in every title, AMD still have lower frametimes in other titles too, so it's not an AMD specific problem.

As matt pointed out, play within settings/gpu capabilities in some titles and the frametimes get back to an acceptable tolerance.
:)
 
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The question is, can you see the difference?

This.

The video Gregg posted although shows what's up, is shot at essentially 4x@60Hz or 2x120Hz(that's the way I see it anyway) and slowed way down on a barren landscape, what happens when both AMD/Nvidia get into a stramash ingame with a few ncp's battling it out?

Do they both still stay the same or would there be no dramatization and less PR(either way)@TR?


Happy New Year Rusty and to Humbug too if I missed you out-I'm loosing track now that auld age is taking over:eek:.
:D
 
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