Bonaire’s Microarchitecture - What We’re Calling GCN 1.1

With our introduction out of the way, before looking at the cards and our performance results we would like to dive into a technical discussion and a bit of nitpicking. Specifically we would like to spend some time talking about architectures and product naming, as it’s going to be a bit confusing at first. As AMD has stated numerous times in the past, Graphics Core Next is a long-term architecture for the company. AMD intends to evolve GCN over the years, releasing multiple microarchitectures based on GCN that improve the architecture and add features while still being rooted in the design principles of GCN. GCN is after all the other half of AMD’s upcoming HSA-capable APUs, the culmination of years of AMD’s efforts with HSA/Fusion.

So where does Bonaire fit in? Bonaire is of course a GCN part; it’s a new microarchitecture that’s technically different from Southern Islands, but on the whole it’s a microarchitecture that’s extremely close in design to Southern Islands. In this new microarchitecture there are some changes – among other things the new microarchitecture implements some new instructions that will be useful for HSA, support for a larger number of compute work queues (also good for HSA) and it also implements a new version of AMD’s PowerTune technology (which we’ll get to in a bit) – but otherwise the differences from Southern Islands are very few. There are no notable changes in shader/CU efficiency, ROP efficiency, graphics features, etc. Unless you’re writing compute code for AMD GPUs, from what we know about this microarchitecture it’s likely you’d never notice a difference.

Unfortunately AMD has chosen to more-or-less gloss over the microarchitectural differences altogether, which is not wholly surprising since they will be selling Bonaire and previous generation products side-by-side. Bonaire’s microarchitecture has no official name (at least not one AMD wants to give us) and no version number. The Sea Islands name we’ve been seeing thrown around is not the microarchitecture name. Sea Islands is in fact the name for all of the GPUs in this wave – or perhaps it would be better to say all of the products created in this development cycle – including both Bonaire and it’s new microarchitecture, and Oland, AMD’s other new GPU primarily for mobile that is purely Southern Islands in microarchitecture.

In fact if not for the fact that AMD released (and then retracted) an ISA document called “AMD Sea Islands Instruction Set Architecture” last month, we would likely know even less about Bonaire’s microarchitecture. The document has been retracted at least in part due to the name (since AMD will not be calling the microarchitecture Sea Islands after all), so as a whole AMD isn’t particularly keen in talking about their microarchitecture at this time. But at the same time from a product standpoint it gives you an idea of how AMD is intending to smoothly offer both Southern Islands and Bonaire microarchitecture parts together as one product family.

Anyhow, for the sake of our sanity and for our discussions, in lieu of an official name from AMD we’re going to be retroactively renaming AMD’s GCN microarchitectures in order to quickly tell them apart. For the rest of this article and in future articles we will be referring to Southern Islands as GCN 1.0, while Bonaire’s microarchitecture will be GCN 1.1, to reflect the small changes between it and the first rendition of GCN.

Ultimately the differences between GCN 1.0 and GCN 1.1 are extremely minor, but they are real. But despite our general annoyance in how this has been handled, for consumers the difference between a GCN 1.0 card like the 7770 and a GCN 1.1 card like the 7790 should be limited to their innate performance differences, and of course PowerTune. GCN 1.1 or not, Bonaire fits in nicely in AMD’s current product stack and is in a position where it’s reasonable for it to be lumped together with GCN 1.0 parts as a single family. It’s really only the technical enthusiasts (like ourselves) and programmers that should have any significant reason to care about GCN 1.0 versus GCN 1.1. For everyone else this may just as well be another Southern Islands part.

Introduction The New PowerTune: Adding Further States
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  • Death666Angel - Friday, March 22, 2013 - link

    "pulling 7W more than the 7770, a hair more than the 5W difference in AMD’s TBP"
    That 5W is not at the wall though. Factoring in rounding PSU efficiencies, it's very possible that the cards are only drawing 5W more. :)
    "The Sapphire card, despite being overclocked, draws 6W less than our reference 7790."
    Seeing how the Sapphire runs cooler in Furmark, that might explain a Watt or two in reduced power draw, coupled with the efficiency of the PSU, it might explain three or four even. :)
    Reply
  • pandemonium - Saturday, March 23, 2013 - link

    "NVIDIA has for a long time set the bar on efficiency, but with the 7790 it looks like AMD will finally edge out NVIDIA."

    What is your definition of a long time? As far as efficiency standards, I consider AMD to be better for the end result when looking at the full definition and application of the word. See the spreadsheet I created here about 16 months ago to understand what I mean: http://forums.anandtech.com/showthread.php?t=21507...
    Reply
  • silverblue - Saturday, March 23, 2013 - link

    You just called Ryan a "dummy", did you, without even checking the statement further down which reads:

    "For anyone looking to pick up a 7790 today, this is being launched ahead of actual product availability (likely to coincide with GDC 2013 next week). Cards will start showing up in the market on April 2nd, which is about a week and a half from now."

    If YOU had read the article, blah blah dumb idiot blah blah. As you've not replied to anybody in particular, your mistargeted rants could be construed as being directed toward the staff themselves, so keep it up and you won't HAVE to worry about what AT is reviewing in future.

    Bottom line - it's faster than the 650 Ti, it's looking to be more efficient than the 650 Ti, and oh look, both have 1GB of GDDR5 on a 128-bit memory interface, which you seem to have forgotten when you leapt down AMD's throat about the 7790, and when you went on your childish tirade about the 5770's 128-bit memory interface earlier.

    As far as I recall, Ryan didn't mention anything about when Titan was available to buy, only that it had launched. Pretty much blows your theory of Ryan hating NVIDIA out of the water, doesn't it?

    I'm not sure if I've said this before, and apologies to everybody else if I have, but I'm done with you, full stop. I can only hope everybody else here decides that not feeding the ignorance you perpetuate on every single AMD article would save them time they could be devoting to something far less boring instead.

    To the staff - is there anything you can do to introduce an Ignore List? Thanks in advance for your response.
    Reply
  • silverblue - Saturday, March 23, 2013 - link

    A note about threading - doesn't look to be stepping in consistently, so sometimes it's a little difficult to see whom replied to whom. Reply
  • CeriseCogburn - Sunday, March 24, 2013 - link

    You got eveything wrong again, and you failed to read the article not I, and you failed to read my reply addressing half your idiotic non points, so you're the non reader, fool.
    Now I have to correct you multiple times. And you're a waste.
    650TI overclocks and it's only faster in a few amd favor games which are here, of course.
    Strike one for tardboy.
    650Ti runs fine OC'd too, which it does well: " We pushed Gigabyte's GeForce GTX 650 as far as it'd go and achieved a maximum core overclock of 1125 MHz, with the GDDR5 memory operating at 1600. All it took was a 1.15 V GPU voltage. "
    http://www.tomshardware.com/reviews/geforce-gtx-65...
    The 128 bit bus - REPAYMENT for you FOOLS SQUEALING prior, what's so hard to understand ?
    Did you forget all your WHINING ?
    Did you forget your backing up the FAILED theorists with the nVidia dual speed memory ?
    ROFL
    You're up to strike 4 already.
    " Ryan didn't mention anything about when Titan was available to buy, only that it had launched. Pretty much blows your theory of Ryan hating NVIDIA out of the water, doesn't it?"
    NO, so why would it be mentioned if he didn't want anyone to buy it ? Why mention it, that would key in to save for release date, right ?
    Instead we get this gem first off in BOLD to start the article: " Who’s Titan For, Anyhow? "

    Guess that just crushed your idiot backwards bullhockey forever.
    For all you know Ryan mentioned release date anyway.

    You're not "done with me", you get everything WRONG, so you'll be opening your big fat piehole forever, that's how people like you do it. Idiot amd fanboys, all the same.

    Also a beggar child for extra "control", since you "can't be an adult and control yourself" - please give me an ignore button ! I'm a crybaby who can't handle it !
    ROFL
    Reply
  • philipma1957 - Sunday, March 24, 2013 - link

    One question does your 650Ti pays for itself? this amd will pay for itself via bitcoin. even with the asics. especially if you heat your home with electrical heat.

    nuff said
    Reply
  • Rajan7667 - Sunday, March 24, 2013 - link

    @form @LinusTech This is new New app for intel lovers. http://www.intel.com/content/www/us/en/gamers/vip-... Reply
  • colonelclaw - Sunday, March 24, 2013 - link

    To Ryan and staff
    As a long-time admirer of AnandTech, I always enjoy reading pretty much every article you post, and have immense respect for all your writers.
    However, I am now utterly fed up with the direction the comment discussions have taken. The general pattern is they start out as debates and end up as pretty nasty personal attacks that have nothing to do with the articles. You may say 'don't read the comments', to which I reply that they used to be an extension of the articles themselves, and were always a source of valuable information.
    It pains me to say this, but if you don't start removing the trolls I will no longer come to this site at all, and I would guess I am not alone in having this opinion.
    Reply
  • haze4peace - Sunday, March 24, 2013 - link

    I agree 100% and actually sent off a few emails to the staff earlier in the day. I urge others to do so as well so we can put this problem behind us. Reply
  • KnightRAF - Monday, March 25, 2013 - link

    I agree the trolls are out of control and need some pruning back. They have massively lessened my enjoyment of the site the last couple of times I've visited. Reply

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