Final Thoughts

Throughout our entire review we’ve been calling the Radeon R9 285 a lateral for AMD, and as we’ve seen in our results this is for a good reason. Despite all of the architectural and feature changes between the R9 285 and its R9 280 predecessor – everything from the GCN 1.2 feature set to color compression to the smaller VRAM pool – the R9 285 truly is a lateral for AMD. At the end of the day it brings a very minor 3-5% performance increase over the R9 280 with virtually no change in price or power consumption. Functionally speaking it’s just an R9 280 with more features.

To that end laterals like the R9 285 are currently an oddity in the video card landscape, but it’s something that we should expect to see more of in the future. As GPU architectures mature and the rate of progress on new manufacturing nodes continues to slow, we no longer have the same yearly or even biennial shakeup in the GPU landscape. Tahiti at this point is nearly three years old and is still going strong, and the 28nm process it’s built on is going to be with us for a while yet. Which means newer generations of video cards are going to be farther apart, and a new opening is created for smaller refreshes such as Tonga and GCN 1.2.

From a feature standpoint then, Tonga and the underlying GCN 1.2 architecture is a small but nonetheless impressive iteration on what AMD has already done with GCN 1.1. I think it’s going to take some time to really see the impact of the newer ISA, but the improvements to geometry performance and color compression are very immediate and very potent. The fact that AMD has been able to offset a roughly 30% bandwidth reduction just through the use of color compression is certainly a feather in AMD’s cap, and this is only going to get more important over time as we have hit a wall on GDDR5 clockspeeds and memory bus widths, especially on the high-end. Meanwhile AMD’s upgrades to their video decode and encode capabilities should not go unnoticed; AMD has finally caught up to NVIDIA on video decoding – especially in 4K H.264 compatibility – and the ability to encode 4K H.264 in hardware may yet prove advantageous.

As for R9 285’s customer base and its competition, AMD’s product positioning continues to be straightforward. AMD has continued to undercut NVIDIA on a price/performance basis across the entire Radeon 200 family, and R9 285 upholds this tradition. If we’re just looking for the card with the best performance for the price, the R9 285 solidly outperforms NVIDIA’s GTX 760 by 12-15%, and it’s by no mistake that GTX 760 prices have slid in the last week in response.

The ramification of this is that AMD no longer holds a real price/performance advantage – the price gap just about matches the performance gap at this point – but this does mean that the R9 285 is in its own little performance niche as a more powerful but more expensive video card compared to the GTX 760. The end result is that we have a tossup: you could buy either and be satisfied for the price.

AMD’s lineup on the other hand is a bit more volatile and will remain so until R9 280 stocks run out. With AMD’s partners selling off their remaining R9 280 cards at clearance sale prices, the R9 280 is a very strong value proposition at $210-$220, offering virtually identical performance to the R9 285 for $40 less. However like all GPU discontinuation clearance sales this situation will be fleeting, and at some point R9 280 will go away and $250 R9 285 will be the status quo. In the meantime however one is also left with the harder choice of picking price or features; the R9 285 has a few features that in the long run are going to make a difference, such as full support for DisplayPort Adaptive-Vsync (Freesync) and a 4K capable video decoder, but whether that’s worth a $40 premium is going to be very situational if not outright difficult to justify.

All things considered then the R9 285 is a solid card, however I remain unconvinced that AMD has equipped it with the right amount of memory. From a GPU performance perspective I feel that AMD is overshooting in promoting the R9 285 as a 2560x1440 card, as the raw performance to run at that resolution with high quality settings just isn’t there, but even as a 1080p card 2GB for $250 is tough to swallow and is made all the worse by the 3GB R9 280. 2GB for 1080p is enough for now, but whether that will still be true in 2-3 years seems unlikely. A 4GB R9 285 would be a much safer bet as a result, however it doesn’t necessarily follow that it would be worth a price premium at this time.

Switching gears for a moment, second-tier cards like the R9 285 are often not the strongest showing for a new GPU like Tonga. Given all the similarities between Tonga and Tahiti, it seems like it’s only a matter of time until R9 280X gets the Tonga treatment. And even though it would be the second Tonga card, I think it could prove to be just as interesting as the R9 285 (if not more so), as it will give us a chance to see just what an unrestricted Tonga product can do. To that end, I hope AMD doesn’t leave us waiting too long to release a fully enabled Tonga SKU.

Power, Temperature, & Noise
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  • Alexvrb - Tuesday, September 16, 2014 - link

    "if other GCN 1.1 parts like Hawaii are any indication, it's much more likely the 280 maintains its boost clocks compared to the 285 (due to low TDP limits)"

    This is what you said. This is where I disagreed with you. The 285 maintains boost just as well as the 280. Further, GCN 1.1 Bonaire and even Hawaii reach and hold boost at stock TDP. The 290 series were not cooled sufficiently using reference coolers, but without any changes to TDP settings (I repeat, stock TDP) they boost fine as long as you cool them. GCN 1.1 boosts fine, end of story.

    As far as Tonga goes, there's almost no progress in performance terms. In terms of power it depends on the OEM and I've seen good and bad. The only additions that really are interesting are the increased tessellation performance (though not terribly important at the moment) and finally getting TrueAudio into a mid-range part (it should be across the board by next gen I would hope - PS4 and XB1 have the same Tensilica DSPs).

    I would hope they do substantially better with their future releases, or at least release a competent reference design that shows off power efficiency better than some of these third party designs.
  • chizow - Wednesday, September 17, 2014 - link

    Yes, and my comment was correct, it will ALWAYS be "more likely" the 280 maintains its boost over other GCN 1.x parts because we know the track record of GCN 1.0 cards and their conservative Boost compared to post-PowerTune GCN1.x and later parts as a result of the black eye caused by Hawaii. There will always be a doubt due to AMD's less-than-honest approach to Boost with Hawaii, plain and simple.

    I also (correctly) qualified my statement by saying the low stated TDP of the 285 would be a hindrance to exceeding those rated specs and/or the performance of the 280, and we also see that is the case that in order to exceed those speed limits, AMD traded performance for efficiency to the point the 285's power consumption is actually closer to the 250W rated 280.

    In any case, in another day or two, this unremarkable part is going to become irrelevant with GM104 Maxwell, no need to further waste any thoughts on it.
  • etherlore - Thursday, September 11, 2014 - link

    Speculating here. The data parallel instructions could be a way to share data between SIMD lanes. I could see this functionality being similar in functionality to what threadgroup local store allows, but without explicit usage of the local store.

    It's possible this is an extension to, or makes new use of, the 32 LDS integer units in GCN. (section 2.3.2 in the souther islands instruction set docs)
  • vred - Thursday, September 11, 2014 - link

    And... DP rate at last. Sucks to have it at 1/16 but at least now it's confirmed. First review where I see this data published.
  • chizow - Thursday, September 11, 2014 - link

    It has to be artificially imposed, as AMD has already announced FirePro cards based on the Tonga ASIC that do not suffer from this castrated DP rate. AMD as usual taking a page from Nvidia's playbook, so now all the AMD fans poo-poo'ing Nvidia's sound business decisions can give AMD equal treatment. Somehow I doubt that will happen though!
  • Samus - Thursday, September 11, 2014 - link

    If this is AMD's Radeon refresh, if the 750Ti tells us anything, they are screwed when Maxwell hits the streets next month.
  • Atari2600 - Thursday, September 11, 2014 - link

    The one thing missed in all this - APUs.

    As we all know, APUs are bandwidth starved. A 30-40% increase in memory subsystem efficiency will do very nicely for removing a major bottleneck.

    That is before the move to stacked chips or eDRAM.
  • limitedaccess - Thursday, September 11, 2014 - link

    @Ryan

    Regarding the compression (delta color compression) changes for Tonga does this have any effect on the actual size of data stored in VRAM.

    For instance if you take a 2gb Pitcarin card and a 2gb Tonga card showing the identical scene in a game will they both have identical (monitored) VRAM usage? Assuming of course the scenario here is neither is actually hitting the 2gb VRAM limit.

    I'm wondering if it possible to test whether or not this is the case if unconfirmed.
  • Ryan Smith - Sunday, September 14, 2014 - link

    VRAM usage will differ. Anything color compressed will take up less space (at whatever ratio the color compression algorithm allows). Of course this doesn't account for caching and programs generally taking up as much VRAM as they can, so it doesn't necessarily follow that overall VRAM usage will be lower on Tonga than Pitcairn. But it is something that can at least be tested.
  • abundantcores - Thursday, September 11, 2014 - link

    I see Anand still don't understand the purpose of Mantle, if they did they wouldn't be using the most powerful CPU they could find, i would explain it to them but i think its already been explained to them a thousand times and they still don't grasp it.

    Anand are a joke, they have no understanding of anything.

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