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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fingerbob69 - Tuesday, March 6, 2012 - link
It ain't, the 7870 is faster by 25-33% depending on the res. Price wise it's about 30% more (UK) but that fits with the bump in performance. So, you're wrong.Houdani - Monday, March 5, 2012 - link
Hey! My mom was born on Pitcairn. It's the top of a blown off volcano, only 1x2 miles large. No correlation, I'm sure. Interesting.AlB80 - Monday, March 5, 2012 - link
It beats 6950. 6970 and 7850. Is it correct?haukionkannel - Monday, March 5, 2012 - link
Well these are good card even at this moment! Ofcource we can hope cheaper prizes, but that need at least two competitors and at this moment there is none...And I would not wonder if Kepler will be prices accordingly. Those kepler chip are bigger, if leak are true, so they should be faster and they definitely will be more expensive (if not counting those renamed low end cards tha allso AMD is releasing this time)
AMD is not getting profit (in total) and Nvidia has a lot of new staff going on that need a lot of money to develop, so there seems to be zero reason to both company to reduce the prices... pity but true.
If you have good 5000 or 6000 series card you don't need these (same as if you have good 6600 serieas cpu you don't need ivy...) at this moment. But if you need a lot of power for little power usage these are extremely good and allso as someone said, these are very small chips! So there is a lot of room for a little bit bigger for 8000 series. Tick tock... Seems to be a lot like Intel Ivy vs Hasvell. Ivy does not offer a much compared to sandy, only smaller power usage and a little bit better speed. Like someone else said, very similar situation.
Hubb1e - Monday, March 5, 2012 - link
The upgrade from a 5800 to a 7800 may be only 20-40% on stock clocks, but add in the extra headroom the 7800 has when overclocking and you're looking at a decent upgrade. Once the prices come down on these I'm sure you'll see quite a few folks dropping their 5800 for a 7800.PurpleMoose - Monday, March 5, 2012 - link
The 7850 (usually) slightly outperforms the 6950 despite having only 1024 shaders compared to 1408, with a ~7% core overclock (and a slight memory underclock). Even being conservative, that would make the GCN shaders about a third more efficient than the VLIW4 ones. But if we assume that a VLIW4 cluster performs more or less the same as a VLIW5 cluster, as does seem to be the case, then we can compare a hypothetical VLIW4-based 5770 with 640 shaders to the 7770. In this case the 7770 outperforms the 5770 basically by its clock speed difference, in other words clock for clock, shader for shader, VLIW4/5 vs GCN seems to be a wash.So why doesn't the 7700 series show as much (ie any) improvement?
The most obvious deficiency is the memory bus and memory bandwidth, but if thats the case why not add more? Alternatively, if you're happy with the performance as is, why not cut away a few more shader groups as it seems the card really can't use them, and save even more space? I had a very brief look for overclocked results and couldn't really find any - what I'd find really interesting is if anyone has benched a stock 7770 against a 7750 running at 7770 frequencies. I wonder how much the loss of shaders would hurt.
jesh462 - Monday, March 5, 2012 - link
Whenever I read an article on the new 7xxx series, I can't help but wonder if people remember what they're looking at. AMD moved to 28nm with this series. They also introduced a completely new architecture. They did so with no complications and without going overtime on the release date.This hasn't been done before. Even Intel doesn't attempt to do this with their CPUs. Tick, then tock, right?
Not only did AMD manage to get their new line up out, but the new cards have performance that exceeds their Nvidia counterparts on both the gaming and compute levels, in most cases. People who buy actual retail samples of the 7xxx series are pleased with the great overclocking headroom. It's obvious that there is a lot of room, even in the 7xxx series current iteration, for growth.
Despite all this, I still see people talk about how a 7xxx card isn't worth it, and how AMD is a sh*t company. Really? Ok.
Disclaimer, I own an i7 laptop with a geforce 560 blah blah.. fanboy whatever. Just think about this before you post. Yeah the new cards could use a price drop. We all know they will, sooner or later. That's why it's called the waiting game.
arjuna1 - Monday, March 5, 2012 - link
a 7xxx card is not worth it and AMD is not a sh*t company.I tend to agree with you for the most part but, there are no NVIDIA's counterparts for the 7xxx series, yet, and when there is, the 7xxx will go down in prices and then their value will increase.
CeriseCogburn - Thursday, March 8, 2012 - link
I'm sorry, we were promised southern islands for the 6000 series, and then, all that changed...What we really have here is a release that is like 2 years late.
Apparently once AMD re-announces it's new release schedule after admitting it missed it's last release target... all you people suddenly get a gigantic case of perfect amnesia.
To put it simply this is AN ENTIRE GENERATION LATE ON THE PROMISED RELEASE.
mattgmann - Monday, March 5, 2012 - link
Where is this misconception that the pricing is anywhere near acceptable on these new parts coming from? So they fit right in with the current price/performance ration. So what? AMD has basically put out a new line of cards that match their competitors previous generation and cost SLIGHTLY less.Aren't technologies supposed to get better? What's the point in upgrading if you get basically the same amount of performance for your dollar today as when you bought you last part?
Intel's new top end processors cost the same as last generation's, and the generation before that. New products replace old ones in pricing structures. AMD is raking in cash on these cards. They're less expensive to produce than last generation and retail for MORE money.
AMD is taking full advantage of their current market position, and instead of passing on ANYTHING to the consumer, is milking every profitable drop.
These cards' performance is impressive when compared apples to apples against last generation's equivalents. But since they basically all occupy a price slot a full tier higher than their predecessors, the comparison is moot.
Too bad the only 2 companies in the graphics card race are so ill equipped to advance the industry. AMD, Nvidia, get a clue.