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In 2009-2010, AMD launched the entire 4 chip Evergreen series in 6 months. By previous standards this was a quick pace for a new design, especially since AMD had not previously attempted a 4 chip launch in such a manner. Now in 2012 AMD’s Southern Islands team is hard at work at wrapping up their own launch with new aspirations on quickness. Evergreen may have launched 4 chips in 6 months, but this month AMD will be completing the 3 chip Southern Islands launch in half the time – 3 chips in a mere 3 months.

To that end today AMD is taking the wraps off the final piece of the Southern Islands puzzle: Pitcairn. The middle child of the family, it will be the basis of AMD’s $250+ enthusiast segment Radeon HD 7800 series. We’ve seen AMD capture the high-end with the 7900 series and struggle to control the mainstream market with the 7700 series, but how does the 7800 series fare amidst AMD’s lead in deploying 28nm GPUs? Let’s find out.

AMD GPU Specification Comparison
  AMD Radeon HD 7870 AMD Radeon HD 7850 AMD Radeon HD 6970 AMD Radeon HD 6950 AMD Radeon HD 5870
Stream Processors 1280 1024 1536 1408 1600
Texture Units 80 64 96 88 80
ROPs 32 32 32 32 32
Core Clock 1000MHz 860MHz 880MHz 800MHz 850MHz
Memory Clock 4.8GHz GDDR5 4.8GHz GDDR5 5.5GHz GDDR5 5.0GHz GDDR5 4.8GHz GDDR5
Memory Bus Width 256-bit 256-bit 256-bit 256-bit 256-bit
Frame Buffer 2GB 2GB 2GB 2GB 1GB
FP64 1/16 1/16 1/4 1/4 1/5
Transistor Count 2.8B 2.8B 2.64B 2.64B 2.15B
PowerTune Limit 190W 150W 250W 200W N/A
Manufacturing Process TSMC 28nm TSMC 28nm TSMC 40nm TSMC 40nm TSMC 40nm
Architecture GCN GCN VLIW4 VLIW4 VLIW5
Price Point $350 $250 N/A N/A N/A

So what exactly is Pitcairn? In a nutshell, take Cape Verde (7700) and double it, and you have Pitcairn. Pitcairn has twice the number of CUs, twice the number of ROPs, twice the memory bandwidth, and of particular importance twice as many geometry engines on the frontend. This works out to 1280 SPs among 20 CUs – organized as a doubling Cape Verde’s interesting 4/3/3 configuration – 80 texture units, 32 ROPs, 512KB L2 cache, and a 256-bit memory bus. Compared to Tahiti, Pitcairn still has 12 fewer CUs and as a result less shader and texturing performance along with the narrower memory bus, but it has the same number of ROPs and the same frontend as its bigger brother, which as we’ll see creates some very interesting situations.

On the functionality side of things, the Cape Verde comparisons continue. As with all Southern Islands family parts, Pitcairn supports things such as DX10+ SSAA, PowerTune, Fast HDMI support, partially resident textures, D3D 11.1 support, and the still-AWOL Video Codec Engine (VCE). FP64 support is once again present, and like Cape Verde it’s a performance-limited implementation for compatibility and software development purposes, with FP64 performance limited to 1/16th FP32 performance.

AMD’s Pitcairn cards will be the Radeon HD 7870 GHz Edition and the Radeon HD 7850. The 7870 is a full Pitcairn, clocked at 1000MHz core and paired with 2GB of GDDR5 running at 4.8GHz. It has a PowerTune limit of 190W while AMD puts its typical board power draw closer to 175, meanwhile idle power consumption is around 10W with a long idle of 3W like the rest of Southern Islands. As for the 7850 it’s the typical lower tier part, featuring 16 active CUs (1024 SPs), an 860MHz core clock, and the same 2GB of GDDR5 running at 4.8GHz as its counterpart, giving it roughly 68% the shading/texturing performance and 86% of the ROP & frontend performance of the 7870. The PowerTune limit is 150W with a typical board power of 130W, and the same 10W/3W idle power consumption as the 7870.

Altogether the 7800 series isn’t just the successor to the Barts based 6800 series in name but also the successor to the 6800 in design. This includes not only power consumption, with one card being a sub-150W part, but also with regards to things such as CrossFire, where it features a single CF connector. Interestingly enough even though Barts was already a fairly small chip for its performance, Pitcairn takes this one step further with a die size of 212mm2, which in turn contains 2.8B transistors, only 160M more than Cayman. As we’ll see when we get to our benchmarks, this makes Pitcairn a surprisingly small chip given its 6970+ performance.

Speaking of the 6970, let’s talk about the 7800 series’ competition. As AMD began winding down Cayman (6900 series) almost immediately with the launch of the 7900 series, at this point the 6900 market has effectively dried up. Having taken themselves out of competition with themselves, AMD’s only competition is NVIDIA’s lineup. From a performance and price basis the 7870 and 7850 don’t map particularly well to any specific NVIDIA products, but generally speaking they’re targeted against the GTX 570 and GTX 560 Ti respectively.

With AMD targeting the ~$320 570 and ~$210 560 Ti and given their conservative pricing on the rest of Southern Islands, it should come as no surprise that the 7800 series is priced equally conservatively. The 7870 will have an MSRP of $350, while the 7850 will have an MSRP of $250. With the 7800 series completing the launch of Southern Islands, this gives AMD a consistent price structure for the entire family: $550, $450, $350, $250, $159, and $109.

Finally, as far as availability goes this will be a delayed launch. AMD is formally unveiling the 7800 series today, but it will not go on sale until the 19th, 2 weeks from now. AMD has said that this is due to both CeBIT and the Game Developers Conference; AMD and their partners want to be able to show off the 7800 series to their respective attendees at those events, with both events being far too large to keep the 7800 under wraps. This delayed launch also means that partner cards aren’t quite ready yet, so we only have AMD’s reference cards on hand. We’ll be taking a look at partner cards later this month.

Spring 2012 GPU Pricing Comparison
AMD Price NVIDIA
Radeon HD 7950 $450 GeForce GTX 580
Radeon HD 7870 $350  
  $330 GeForce GTX 570
Radeon HD 7850 $250  
  $200 GeForce GTX 560 Ti
  $179 GeForce GTX 560
Radeon HD 7770 $159  

 

Meet The Radeon HD 7870 & Radeon HD 7850
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  • rburnham - Monday, March 05, 2012 - link

    I tend to skip one or two generations of video cards before upgrading, but the 7850 looks like a fairly respectable upgrade over my current 6850. I love that low power draw, although I might wait until someone like MSI comes out with a quieter version. Reply
  • CeriseCogburn - Thursday, March 08, 2012 - link

    Your 6850 is 2 watts higher power draw at idle. But you're a gamer, so load draw is important. The 7850 is 14 watts higher power draw on normal load, and 26 watts more on high load. Powertune slider only increases that. Reply
  • smoka - Monday, March 05, 2012 - link

    A lot of people are saying power draw is not important, but it is for some of us upgrading. I have been running a GTX460 for about a year now and I'm finally thinking about jumping on the Eyefinity bandwagon. I was eying the 6950 a few weeks ago, but I decided to wait for the 78xx to come out. My plan is to move to a single card and run at a lower resolution (3072x768 or 3840x1024) until I can upgrade to a CF setup and run at 5760x1080.

    Also keep in mind that I have a 600W PSU, which would need an upgrade a 69xx CF or GTX570/580 SLI setup. Many people who are in the mid-high end gaming market (which the 78xx is aimed at) don't have a 1000W PSU. Upgrading to these top-tier PSUs is also another expense to add to an already expensive graphics card overhaul.

    The 7870 series fits the bill exactly for me, except for the $350 price-point. I really wanted the it to be priced at $300 or less. I am hoping it will hit this price either due to brand competition, store promotion, or after kepler release.
    Reply
  • kallogan - Monday, March 05, 2012 - link

    Actually i care about power consumption more than stupid power hungry raw performance.

    You are not responsible citizens when buying nvidia stuff. Buy amd and save the planet.

    HAHA
    Reply
  • compvter - Monday, March 05, 2012 - link

    Sure performance/price matters most, but what i find interesting in current amd generation cards is zerocore that allows me to keep my computer running with low power draw when i don't use it. I don't really care about power draw when i am using computer, but i do care about noise, and those are kind of related. Still most of the cards are silent enough for me, but most of the time my coputer is on idle (or long idle) with software running that i can't turn off (irc client), so zerocore would save me a lot of money compared to Nv offerings. Still i am interested to see what nv offers, but at the moment im considering 7870 to replace my 3870x2. Would go 79xx, but don't want to buy new case =/ Reply
  • mattgmann - Monday, March 05, 2012 - link

    save the planet...lol. Though saving on the electricity bill would be nice. The power hungry 4890 tandem in my rig surely adds a few tens of dollars a month to my bill. Reply
  • pieguy - Monday, March 05, 2012 - link

    In the paragraph about 7800 series voltage, you mention 7950 voltages but I think you mean 7850 voltage, else I am not understanding...

    Also, a question about these voltages of 1.213 - 1.219. I don't know much on the subject. If these are the voltages under load, what are they actually set to (before vdroop)? If this voltage is standard for these cards, does it mean that we shouldn't be concerned about using this voltage on other 28nm 7XXX series cards for extra OC headroom and 24/7 usage? I'm just trying to figure out a max "safe" 24/7 voltage for my 7950 since the overclocking scales really well with voltage increases.

    Thanks for the great review!
    Reply
  • Ryan Smith - Monday, March 05, 2012 - link

    Hi Pie, thanks for the correction. As for the voltages, those are the VIDs, so it's without vdroop. As for what a safe voltage is, there's no easy answer to that. Though 1.21v is likely safe for 7900 cards that are already in the 1.17v range. Reply
  • ObeseMaurice - Monday, March 05, 2012 - link

    I bought a 2GB 6950 2 weeks ago for $240 and $20 mail in rebate. The 7870 is worse on all resolutions of Battlefield 3 and priced significantly higher. Very unimpressive product launch from AMD. Reply
  • silverblue - Monday, March 05, 2012 - link

    Has anybody stopped to think how much extra performance you might get from these cards when AMD has proper drivers for them, or is this considered a moot point? Needless to say, nowhere on the BF3 benchmarks in this review is the 7870 slower than the 6950, rather it's a consistent 20% faster. Throughout the review the 7870 ranges from about 15% (Batman 1920x1200) - 70% (Civ5 1920x1200) faster depending on the title. Granted, the gap isn't always this large at 2560x1600 but it's still sizeable in a good number of cases. Are you in fact referring to the 7850?

    AMD are pricing these cards at that level because they can. It's certainly not going to last forever.
    Reply

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