AMD Frame Pacing Explored: Catalyst 13.8 Brings Consistency to Crossfireby Ryan Smith on August 1, 2013 2:00 PM EST
In an off year that hasn’t seen too many new product releases thus far, this has been anything but a dull time. For the better part of a year now the technology journalist community – spearheaded by The Tech Report’s Scott Wasson – has been investigating the matter of frame pacing and frame timing on GPUs. In applying new techniques and new levels of rigor, Scott found that frames were not being rendered as consistently as we had always assumed they were, and that cards that were equal in performance as measured by frame rates were not necessarily equal in in performance as measured by frame intervals. It was AMD in particular who was battered by all of this work, with the discovery that both their single-GPU and multi-GPU products were experiencing poor frame pacing at times. AMD could meet (and beat) NVIDIA on frame rates, only to lose out on smoothness as a result of poor frame pacing.
Since then we have seen both some progress and some new revelations on these matters. AMD was very quick to start working on resolving their single-GPU issues, and by March when they were willing and able to fully engage the tech community, they had already solved the bulk of those single-GPU issues. With those issues behind them, they also laid out a plan to tackle the more complex issue of multi-GPU frame pacing, which would involve spending a few months to write a new frame pacing mechanism for their cards.
At the same time NVIDIA also dropped a small bombshell with the public release of FCAT, their long in development frame interval benchmarking tool. FCAT could do what FRAPS alone could not, capturing and analyzing the very output of video cards to determine frame rates, frame times, and frame intervals. Though FRAPS was generally sufficient to find and diagnose single-GPU issues, FCAT shed new light onto AMD’s multi-GPU issues, painting a far more accurate – and unfortunately for AMD more dire picture of Crossfire frame pacing.
Perhaps as proof that there’s no such thing as coincidence, since then we have seen the release of AMD’s latest multi-GPU monster, the Radeon HD 7990. Packing a pair of high clocked Tahiti GPUs, the 7990 was AMD’s traditional entry into the realm of $1000 multi-GPU super cards. A capable card on paper, the 7990 has been at the mercy of AMD’s drivers and lack of a frame pacing mechanism, with the previous revelations and FCAT results causing the 7990 to suffer what can only be described as a rough launch.
Ultimately when AMD engaged the community back in March they had a clear plan for addressing their multi-GPU frame pacing issues, developing a new frame pacing mechanism for their cards. AMD stated outright that this work would take a few months, something of an arduous wait for existing Crossfire users, setting a goal that the new frame pacing mechanism would “come in or around a July driver drop.” July has since come and gone by a day, but at long last AMD has completed their initial work on their new frame pacing mechanism and is releasing the first public driver today at 2pm ET as Catalyst 13.8 Beta 1.
As part of today’s launch activities, AMD seeded the beta driver to the press a week in advance to give us a chance to put it through the necessary paces, give AMD feedback, and write up about our experiences with the new driver. Over the next several pages we’ll be going over what changes AMD has made to their drivers, how they impact the 6 games we do frame interval testing with, and ultimately whether AMD has made sufficient progress in resolving their frame pacing issues. Make no mistake: AMD wants to get past these frame pacing issues as quickly as possible and remove the cloud of doubt that has surrounded the 7990 since its launch, making this driver launch an extremely important event for the company.
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waldoh - Thursday, August 1, 2013 - linkIts unfortunate it a competing company to shine light on an issue for another to address it.
waldoh - Thursday, August 1, 2013 - linktook*
tackle70 - Thursday, August 1, 2013 - linkI'd say it's more like expected than unfortunate. This is why competition is a good thing and why you never want one company to blow away another - competition makes all companies serve their customer better.
Big time kudos to AMD for their work on this; it's nice to see real competition available again in the $500+ market.
Rezurecta - Thursday, August 1, 2013 - linkExcellent and well said.
HisDivineOrder - Thursday, August 1, 2013 - linkI think he was referring to the fact that this issue was present for many years and not only did reviewers not catch on despite common complaints (and HardOCP) discussing the issue, but the company making the card was apparently completely blindsided by it after years and years of Crossfire sales. That's why people who own only one company's cards should try the other side to see that sometimes when someone says something like, "The nVidia cards are smoother in SLI than CF," sometimes--just sometimes--that's not fanboyism. Sometimes, it really is just smoother.
No, I think the, "it took a competing company to shine a light on an issue," was more in reference to the fact that nVidia had to basically take AMD by the hand and slowly walk them through how to detect a problem highly prevalent on their products after years and years of waiting for them to get it.
They had to take out their own measurement software they built custom in-house and actually hand it over to the other team just to help them get it. This isn't typical competition teaching the other guy what to do.
This is like Pepsi-Cola taking Coca-Cola by the hand and saying, "Okay, so soda is supposed to have sugar and caffeine. Here is where you get it. Here is our supplier. Try it."
That's why he's saying it's sad. If AMD had figured it out on their own and fixed it, then yeah, that's competition because they FIGURED IT OUT. Instead, they didn't. It took TechReport slamming them on it with DATA after years of HardOCP just slamming them without data and thousands upon thousands of users saying, "Crossfire is not very good compared to SLI" and then nVidia hand delivering them FCAT for them to get it.
Before that, they were clueless. AMD is a company that produces discrete GPU's for the gaming market and not only did they have no clue how to test for this problem, they didn't even know there WAS a problem they were so clueless.
And that truly is very sad.
Galidou - Thursday, August 1, 2013 - linkNot sure that it was as much present in past products, I owned crossfire 6850s for a while then switched to a single 660ti to gain not much except lower temps and a little more FPS. Only game I could tell there was a real noticeable difference in smoothness was Skyrim and that was mainly because of thextures taking more than the mere 1gb my 6850s had.
chizow - Friday, August 2, 2013 - linkCan't really agree with this, microstutter was documented and covered significantly in the German press for years, largely ignored by the NA press. 4870X2 microstutter problems were the first time the issue was really brought to light by PCGamesHardware, there's tons of documentation about it about if you search, here's the original test by PCGH:
Death666Angel - Saturday, August 3, 2013 - linkMulti GPU stuttering was well known about pretty much a few months into having multi GPU solutions. The issue with single GPUs also experiencing uneven frame pacing is much newer. And the believe among AMD was that it was an issue that affects AMD and nVidia equally, which is why they never thought about changing it in their drivers. Until Scott made the revelations.
taltamir - Monday, August 5, 2013 - linkI personally documented single GPU multistuttering years ago (caused by lack of CPU power (C2D 8400, problem resolved going to a Q6600; using nvidia GPU), with hard data. (fraps individual frame render times record).
I posted it on anandtech forums and there was a brisk discussion of it. It wasn't well known, but it shouldn't have completely blindsided the so called professionals. HisDivineOrder really said it best
chizow - Wednesday, August 7, 2013 - linkYes I remember, there was a lot of user testing that stemmed from the initial reports on PCGH and the FRAPS frametime methodology became standard in allowing virtually any user who could download FRAPs and work a spreadsheet illustrating microstutter.
I do agree though, the pros and press kept ignoring and sweeping it under the rug as if it didn't exist despite countless requests from end-users asking for more detail on it.