[Andrew Lauritzen]

Originally Posted by 3dilettante

The otherwise steady-state nature of the graph and zero real improvement beyond frames whose submission is held up by the engine makes me think that this isn't a case of trying to optimize the next few frames for benchmark numbers, but some kind of glass jaw in whatever the system is doing to maintain the average performance numbers.

Completely agreed, see my clarification to caveman-jim above. I didn't mean to imply that or attempt to explain what's going on in this specific case... it was just another example of why measuring and optimizing for frame rates is a bad plan.

Originally Posted by 3dilettante

Is something being juggled over the PCIe bus, or some kind of memory buffer issue?

Could be any number of things for that one specific case really, and it should be easy for AMD to track down as it's almost certainly a CPU-side issue. But my point is really not about this specific case, but rather than stuff like this shouldn't ever get through QA/review and it has in the past and still does simply because of using bad performance metrics like FPS.

Originally Posted by Dave Baumann

There is no one single thing for, its all over the place - the app, the driver, allocations of memory, CPU thread priorities, etc., etc. I believe some of the latency with BL2 was, in fact, simply due to the size of one of the buffers; a tweak to is has improved it significantly (a CAP is in the works).

Great, and that's exactly the desirable outcome for everyone really. No need to freak out about stuff like many commenters have, but we definitely want to catch and correct issues like this, and I'm sure there are many more and lots of blame to spread around; let's just get to fixing it all To be clear, I'm not picking on AMD or anyone else here... there's lots of issues to go around. This is more a call to action for the whole industry to improve how we measure and optimize for gamers.

Originally Posted by caveman-jim

I understand and agree, although FPS still has an important place in reviewing. Smoothness at specific settings and FPS rate needs to be known for consumers to get a balanced idea of the performance.

"Smoothness at particular settings" sure, and frame latencies are a good place to start to measure that. Certainly you can argue over whether 99% percentile, time beyond some threshold, quartile graphs, etc. are the best way to present the data, but averaging successive frames is pretty clearly not a good way to present it. FPS is really only meaningful and interesting if it's metered like on many console games (i.e. a "30fps" or "60fps" game), and even then you still want to measure "dropped" frames and such. FPS really does not add any interesting information over frame times, and I don't think there's a compelling reason that it needs to be used in reviews other than legacy. I'm convinced that the enthusiasts who read these sorts of reviews (don't kid yourself, regular people do not...) can understand and adapt.

But hey, more data is all good in my books I just don't ever want to see only FPS numbers for any review that claims to tell me how smooth my gameplay experience is going to be with a specific game, set of hardware, etc.