[TechReport] Re-examining the unusual frame time results in our Radeon RX 470 review

[Bacon1]

http://techreport.com/blog/30506/re...rame-time-results-in-our-radeon-rx-470-review

It's never fun to admit a mistake, but we made a big one while writing our recent Radeon RX 470 review. That piece was our first time out on a new test rig that included an Intel Core i7-6700K CPU and an ASRock Z170 Extreme7+ motherboard. Once we got that system up and running, it delivered some weird-looking frame time numbers with some games. For example, the spikiness of the frame-time plot below didn't match any test data we had ever gathered before for Grand Theft Auto V, and we puzzled over those strange results for some time. We decided to go ahead and publish them anyway after doing some extended troubleshooting without seeing any improvement.

The fallout
Having solved the underlying problem, I now had to contend with the fact that I had published a very public and widely-read review that contained what seemed like reams of contaminated data. To see just how wrong I had been in my conclusions, I retested every title we had slated for our RX 470 and RX 460 reviews on our ASRock test rig, using the same settings we had initially chosen for our reviews.

As it turns out, high DPC latency doesn't affect every game equally, or at least not in a way that shows up in our frame-time numbers. While GTA V, Hitman, and Rise of the Tomb Raider all showed significant changes in average FPS and 99th-percentile frame times after a retest on the updated hardware, Doom, Crysis 3, and The Witcher 3 did not. That second trio of games certainly felt more responsive to input after the critical firmware update, but the data they generated wasn't meaningfully different.

Good to see they took the time to research the issue and fix it, as well as providing updated test results.

This also shows why its good to use multiple reviews for your information as we've seen two sites now have major issues with their results (Techpowerup being the other) recently.

 

[Phynaz]

Props to them, it takes balls to own up to your mistakes in public. Glad I'm a supporter.

 

[nerp]

They obviously rushed. And why they'd be using a beta BIOS for a testing platform is beyond me. Good for them fixing it though.

 

[Erenhardt]

I don't want to be that guy, but... their results still look very strange. The gap between 470 and 480 is some games is huge! Is it because of 4GB mem?

 

[raghu78]

I don't want to be that guy, but... their results still look very
strange. The gap between 470 and 480 is some games is huge! Is it because of 4GB mem?

yeah. 8GB is making a big difference in GTA V according to techreport

http://techreport.com/review/30473/amd-radeon-rx-470-graphics-card-reviewed/3

"The somewhat furrier frame-time graph for the RX 470 versus the RX 480 in GTA V is one case where we might be observing the difference that 8GB of memory makes on the beefier Polaris card, as well. With GTA V's "extended distance scaling" maxed, the RX 470, the R9 380X, and the GTX 960 all appear to be swapping data in from main memory often, while the RX 480 appears to be able to keep all the assets it needs in its pool of GDDR5. I'm guessing that keeping that data local has a noticeable impact on smoothness and performance."

Right now custom Rx 470 4GB makes sense at USD 179. custom Rx 480 8GB is worth getting at USD 250-USD 260.