AMD Radeon HD 7870 GHz Edition & Radeon HD 7850 Review: Rounding Out Southern Islands
by Ryan Smith on March 5, 2012 12:01 AM ESTIn 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 | ||||
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Exodite - Tuesday, March 6, 2012 - link
I have absolutely no problem with that.The apt comparison would be the 7900 series though, and those only really fail on price.
Which will likely change if Nvidia brings something competitive to the high end with Kepler.
Lets face it, until the current consoles die in a fire and/or display makers see fit to bring sensibly priced >1080p panels to the desktop there's really no need for more performance in the desktop space.
SlyNine - Monday, March 5, 2012 - link
The fact the things are sitting still.I'm running a 5870 which is basically 75% the performance of a 7970, and I paid 379 for the 5870. Which is also 75% of the cost of a 7970. The price of a 7970 is basically the exact same price structure as the 2 1/2 year old 5870, So we are stuck where we were in 2009, yay.
This is NOT how the computer world is supposed to work, and as big geek, I don't like it.
morfinx - Monday, March 5, 2012 - link
75% performance of 7970 would mean that it's 33% faster than a 5870. And that's just not accurate. I have a 5870 as well, so I was paying a lot of attention on how much faster the 7970 is in various reviews. Everything I've read indicates that it's anywhere from 70-110% faster at 2560x1600 resolution (I run 3600x1920, so likely even even more of a difference). That's not even even considering the massive overclocking headroom of the 7970 vs barely any OC headroom of the 5870. Overclocked, a 7970 is easily twice as fast as a 5870.Alpert - Tuesday, March 6, 2012 - link
The 6950 retailed for $299 and the 6970 retailed for $369 when they were released. 10-25% performance increase for every new series of cards is what to expect. Now we can clearly see these card perform better then the 6950/6970, hell a 7850 overclocks to what a GTX580 is capable of.The value of what was a $600 GTX580 card more then a year ago, The value of a $499 GTX580 today, you get a $300 7850.
The price you pay for performance is always going down just not in big steps.
Logsdonb - Monday, March 5, 2012 - link
These should be excellent cards for crossfire solutions, especially when combined with the new PCI 3.0 bus system. They represent significant improvements in heat, power, and noise at their performance levels. I think these would work well in small form factor gaming PCs, especially when combined with the upcoming Ivy Bridge CPUs, which max out at 77 watts. I don't want a loud, space heater that sucks down massive power for a computer. I have also noticed that cooler systems tend to last longer and have few problems. I feel confident that the prices will come down once the competition from Nvidia comes out next month.I am thinking that we are approaching a really nice time to upgrade if you like balanced systems that deliver excellent gaming performance in reasonable portable packages that wont disturb your personal environment with excess heat and noise. I intend on waiting for Ivy bridge and Kepler before pulling the trigger, but I am eagerly awaiting upgrading evertyhing.
claysm - Monday, March 5, 2012 - link
The price point on the 7xxx series cards seems to be a little too high at the moment, the only advantage they have is that that do outperform the GTX 5xx series cards in a number of ways (power consumption, performance, temps). The biggest problem with the 7xxx series is that they just don't perform that much higher at each price point than AMD's current 6xxx series cards. Why get a 7770 when you can, for the same money and MUCH more performance, get a 6870? The prices will drop when Kepler rolls around I'm sure, but for now, a little too high, given that most of the increases at each price point don't come in the realm of performance.CeriseCogburn - Thursday, March 8, 2012 - link
AMD has been listening to their little screaming fans who wailed that electric usage and core temps are all the rage....So now the amd fans need to PAY UP SOME $$$ for the nice electric consumption and core temp reduction... let's face it - they have told us all for years now those two things alone are well worth a purchase decision, PERIOD.
I guess it's time for them to dig down deep since their Master has responded with everything they declared of utmost importance.
What's wrong AMD fans ?
BrightCandle - Monday, March 5, 2012 - link
I would love to see Anandtech start to look into the stutter/inconsistent frame problems with these modern graphics card reviews. The techreport has been doing a good job in blowing the lid on the problem, but you guys should be able to start to apply pressure to AMD/NVidia to improve the situation. The minimum average is not the worst it can be, the worst frame time is what you need to worry about. Averages over a second just aren't accurate enough.loeakaodas - Monday, March 5, 2012 - link
These look like great performing cards that need a $50~$100 price drop & hopefully nVidia's new offering will force AMD to compete like they did with the legendary 4800 & 5800 series. I was hoping for a sensible upgrade path from my 2x5850's but it doesn't look like that exists yet, at least not at these price points. I'm better off of putting that money towards a large SSD upgrade, otherwise this midrange 2.5 year old system doesn't really beg for an upgrade.ET - Monday, March 5, 2012 - link
The OC 7850 beats everything hands down at the 2560x1600 resolution, which doesn't look right considering the rest of the benchmarks.Also, on the Skyrim benchmark page the writeup has "GPUs GPUs" on it.