Review Index:

AMD Radeon R9 285 2GB Graphics Card Review - Tonga GPU Debut

Manufacturer: AMD

Tonga GPU Features

On December 22, 2011, AMD launched the first 28nm GPU based on an architecture called GCN on the code name Tahiti silicon. That was the release of the Radeon HD 7970 and it was the beginning of an incredibly long adventure for PC enthusiasts and gamers. We eventually saw the HD 7970 GHz Edition and the R9 280/280X releases, all based on essentially identical silicon, keeping a spot in the market for nearly 3 years. Today AMD is launching the Tonga GPU and Radeon R9 285, a new piece of silicon that shares many traits of Tahiti but adds support for some additional features.

Replacing the Radeon R9 280 in the current product stack, the R9 285 will step in at $249, essentially the same price. Buyers will be treated to an updated feature set though including options that were only previously available on the R9 290 and R9 290X (and R7 260X). These include TrueAudio, FreeSync, XDMA CrossFire and PowerTune.

View Full Size

Many people have been calling this architecture GCN 1.1 though AMD internally doesn't have a moniker for it. The move from Tahiti, to Hawaii and now to Tonga, reveals a new design philosophy from AMD, one of smaller and more gradual steps forward as opposed to sudden, massive improvements in specifications. Whether this change was self-imposed or a result of the slowing of process technology advancement is really a matter of opinion.

Continue reading our review of the AMD Radeon R9 285 Tonga GPU!!

The New AMD Tonga GPU 

By addressing the $250 market first with Tonga and the Radeon R9 285, AMD is hoping to bring a significant portion of its product line up to par when it comes to the feature set it made available in the Radeon R9 290/290X last fall. Looking at raw specifications of the R9 285 will likely induce a case of deja vu for most PC Perspective readers.

  Radeon R9 280X Radeon R9 280 Radeon R9 285 GeForce GTX 760
GPU Cores 2048 1792 1792 1152
Rated Clock 1000 MHz 933 MHz 918 MHz 980 MHz Base
1033 MHz Boost
Texture Units 128 112 112 96
ROP Units 32 32 32 32
Memory 3GB 3GB 2GB 2GB
Memory Clock 6000 MHz 5000 MHz 5500 MHz 6000 MHz
Memory Interface 384-bit 384-bit 256-bit 256-bit
TDP 250 watts 200 watts 190 watts 170 watts
Peak Compute 3.4 TFLOPS 2.9 TFLOPS 3.29 TFLOPS 2.2 TFLOPS
MSRP Price $289 $239 $249 $239

View Full Size

With 1792 stream processors, 112 texture units and 32 raster operation units, the GPU core specs essentially mirror that of the Radeon R9 280 that this new offering is replacing. The "up to" frequency of the GPU however changes from 933 MHz to 918 MHz, a slightly lower speed however peak theoretical performance goes from 2.96 TFLOPS to 3.29 TFLOPS. Clearly the newer architecture has allowed AMD engineers to spend some time tweaking the organization of the Compute Units in a way to improve overall efficiency.

View Full Size

The TDP of the Radeon R9 285 is 190 watts, 10 watts lower than the R9 280 was rated at when it launched. That might seem pretty minor (and it is) but considering that AMD is able to outperform the R9 280 with Tonga with lower power consumption, while on the same architecture and the same process technology, is a good sign.

View Full Size

AMD updated the instruction set on Tonga as well to improve both parallel processing performance and power efficiency for GPU compute and media processing tasks. While details on the sharing improvements between SIMD lanes is sparse, we can assume that some additional cache was setup to allow better communication between Compute Units.

Easily the biggest change is the move from a 384-bit memory bus and a base 3GB of frame buffer on the R9 280 to a more modest 256-bit memory bus and 2GB of memory on the new Radeon R9 285. AMD has stepped up the memory frequency from 5.0 GHz to 5.5 GHz on the R9 285 though it's clear that raw memory bandwidth is lower on Tonga. To make up for this, AMD has improved compression on frame buffer color data, improving bandwidth efficiency by as much as 40% over Tahiti.

The die size of Tonga compared to Tahiti actually goes up slightly, from 352mm2 to 359mm2. Transistor count is much more impressive though - Tonga clocks in at 5.0B transistors; Tahiti just crossed the 4.3B mark. Even though Tonga has 700M more transistors than Tahiti, AMD was able to maintain a comparative die size with that memory controller bus change and some clever engineering.

View Full Size

The Tonga GPU is improved in other ways as well; it would seem the lack of pressure to get a 20nm GPU out the door has allowed AMD's teams opportunity to tweak GCN. The tessellation system in Tonga can now handle 2-4x the total throughput of Tahiti helping to make up for the performance deficit it has had to Kepler. 

View Full Size

The display controller technology has been updated for all six supported outputs with better filters and scaling support all way up to and down from 4K.

View Full Size

Another change for Tonga is that it supports 4K video encoding/decoding, something that even Hawaii doesn't include. By enabling support for 4K h.264 content in fixed function hardware, AMD claims to have as much as a 47% performance advantage over NVIDIA's GeForce GTX 760 using applications like Cyberlink Media Espresso and Arcsoft Media Converter 8.

View Full Size

The best way to think of the new Radeon R9 285 is that it combines the price point of the R9 280 and the feature set of the R9 290X. That includes improved Mantle support, TrueAudio technology, FreeSync support, the improved PCIe-only XDMA CrossFire technology and updated PowerTune.

View Full Size

While TrueAudio and XDMA support are important for the Radeon R9 285 I think support for FreeSync is the most crucial point here. With AMD attempting to counter NVIDIA's G-Sync technology with Project FreeSync, the biggest hurdle was the lack of compatible GPUs on the market. Until this release, only the R9 290X, R9 290 and R7 260X were going to be able to run FreeSync monitors when they become available. That isn't even close to the majority of the market and NVIDIA can claim G-Sync support for any GPU back to the GTX 650 Ti Boost. AMD needs to refresh the remaining product line to make sure that FreeSync has the best possible chances for adoption upon launch.

View Full Size

Pricing on the R9 285 will start $249, just about $20-30 lower than what the Radeon R9 280 launched at, fitting right between the R9 270X and the R9 280X, for as long as those two parts actually last.

September 2, 2014 | 08:24 AM - Posted by Charlie Pearce (not verified)

Ryan - is the 250w TDP listed in the table on page one, for the 280 correct? I thought it was 200w?

As soon as the Asus Strix version of this hits, I think I'm finally upgrading.

September 2, 2014 | 08:51 AM - Posted by Ryan Shrout

Ooops, yep, you're right!

September 2, 2014 | 02:54 PM - Posted by JohnGR

A few days back I was really confused with power consumption of 280 with others mentioning 250W and others 200W. From a little search 280 is indeed 250W, 7950 Boost was 225W and the first 7950 was 200W.
Maybe have another look about these numbers?

September 3, 2014 | 04:35 AM - Posted by JohnGR

AMD's slide

September 3, 2014 | 05:28 PM - Posted by fade2blac

Also in the same table the values listed for the "Peak Compute" seem potentially misleading. The quoted values for Tahiti GPUs are for the minimum/base core clock speeds, not the "Rated Clock", boost, "up to", max, or whatever you want to call them clock speeds. I would question using "Peak" to classify these values. Do you happen to know if the compute value for the R9 285 is also at it's base/minimum clock speed? If so, what is it's minimum clock speed?

If we interpret "Peak Compute" to be theoretical single-precision FLOPS at max/"up to" clocks, then a Tahiti PRO, aka. 7950/R9 280, @827MHz = 2.964 TFLOPS, but @933MHz = 3.344 TFLOPS. Similarly, a Tahiti XT, aka. 7970/R9 280X @850 MHz = 3.481 TFLOPS, but @1000MHz = 4.096 TFLOPS.

This points to a bit of detail that is not usually provided in GPU reviews even after the whole R9 290X/290 launch drama over thermal/power throttling, UBER mode, etc. This was a real problem with my Sapphire 7950 Boost card too. Do you know if the R9 285 was throttling during testing or if it was able to maintain boost clocks throughout? Do you know what voltages are being used?

My 7950 Boost BIOS pumped 1.25V into the GPU in boost mode which caused obvious clock speed throttling under stock settings. Maxing out Power Tune cured most of the throttling but it still ran hot due to the (excessive) voltage. Switching to a non-Boost BIOS allows me to specify a lower 1.169V and run 150MHz over stock (1075MHz) without any throttling. This also lowers max temperatures and noise.

September 2, 2014 | 08:40 AM - Posted by Anonymous (not verified)

Tonga is very inefficient.

September 2, 2014 | 08:49 AM - Posted by still waitin (not verified)

Is it? According to GURU3D, it consumes 52 Watts less than the 280x despite being almost as fast.,5.html

September 2, 2014 | 08:51 AM - Posted by Ryan Shrout

This is the problem with power consumption numbers. Depending the game and HOW you measure the power draw, the variance in results can be HUGE.

September 5, 2014 | 07:59 PM - Posted by fade2blac

I think AMD model numbers and re-branding are as much to blame as anything for the confusion. The R9 285 (190W TDP spec) performs on par with (and is meant to replace) the R9 280 (250W TDP spec). A 60W drop in TDP would appear to be a vast improvement in efficiency, but reviews seem to imply that the difference at the wall is much smaller (~20W) once you account for OC vs stock clock versions.

In general, TDP is proportional to electrical power used, not equal to it. Could this difference in TDP spec compared to power at the wall imply that Tonga generates proportionately less waste heat rather than consumes less electrical power compared to Tahiti?

Few review sites have comparable numbers for all incarnations of Tahiti-based products. For example, there is a noticeable difference in power usage between a 7950, a 7950 Boost, and an R9 280 due to voltages and clock speeds. At least they are all based on the same silicon with the same amount of VRAM so power comparisons are easier to make. Now add Tonga to the mix which has a similar die size, 700M more transistors, 33% smaller memory system, and requires lower voltages to achieve higher clock speeds from what I have seen. There are many variables. Some should reduce power needs and some increase power needs.

AMD seemed in no hurry to release the R9 280 in the first place. With Tonga, AMD is essentially back filling their product stack to bring feature parity (FreeSync, XDMA, TrueAudio, etc.) to this price point. It is disingenuous for AMD to promote these features and then keep re-branding old GPU's that don't support them. Being stuck at 28nm for this long probably forced some awkward/bad release cycles. Tonga feels like a careful balance of compromises which are unfortunately late to the party. At least it provides a way to fill some pot holes and test out additional tweaks to the GCN architecture.

September 2, 2014 | 09:15 AM - Posted by Anonymous (not verified)

tomshardware reports around 178w on typical gaming and maintains below 200w when overclocked

September 2, 2014 | 09:57 AM - Posted by Anonymous (not verified)

Why is not registered if the DP 1.2a supports ???

September 19, 2014 | 12:08 AM - Posted by arbiter

displayport 1.2a was thing for AMD's adaptive sync which nvidia won't support.

September 2, 2014 | 10:02 AM - Posted by General Lee (not verified)

While it might be slightly more power efficient, it's nowhere near what Nvidia achieved with the 750 Ti. Granted these are two different performance classes so it remains to be seen if Nvidia will achieve the same in a performance class card.

The bandwidth efficiency and tessellation performance increase is nice to see, and promising for future cards. But if AMD can't improve power efficiency I don't think that's going to help much.

That said, Nvidia's offerings at this price point suck pretty bad, so I guess 285 wins by default. I say get a 280 while there's still stock left. I'm guessing they'll also bring out the full Tonga 285X soon that'll beat the 280X in a similar way.

September 2, 2014 | 08:40 PM - Posted by arbiter

Less you are dieing for a gpu now, likely best to wait for nvidia's new cards to come out and see what performance comes outta then before making a choice. Worst case drives prices down some.

September 2, 2014 | 11:52 AM - Posted by beckerjr

3 years later and we are still getting the same 28nm parts. Meanwhile Intel has stopped increasing in performance because AMD can offer nothing anymore. This has got to be the worst stretch of stagnation for the PC hardware world I can remember...

September 2, 2014 | 01:42 PM - Posted by spiced (not verified)

it is true that intel and amd have stopped reducing size in chips but this is mostly do to the fact that at the area of 8-10 nm quantum tunneling occurs and chips become more and more inefficient.until they come up with another material like graphene to replace silicon we will not see chips much smaller than 10-15 nm.this being said AMD still has some way to go befor 18nm. the main reason they have not done so yet is the fact that amd chips (gpu and cpu) are underrated by most people. meaning they don't have as much funds to pay for R&D and nvidia as well as intel dont have a reason to push R&D as AMD is still trying to catch up.(AMD made 83 mil last year in the cpu and gpu market, intel made 10 bil).thought nvidia is planning a 18nm acturture for 2015-16 ish this being maxwell.IBM is doing R&D right nor for graphene chips although it seems its a far way off 2020 maby.
sorry for all the shitty grammar.

September 2, 2014 | 08:38 PM - Posted by arbiter

intel is working on smaller die's AMD well not so much they rely on big fabs to do it.

September 2, 2014 | 02:33 PM - Posted by ZoA (not verified)

Dude double patterning is hard, give them time. It is not conspiracy, it is just that hard to manufacture at that level when key technologies as UV lithography are not available.

September 2, 2014 | 08:00 PM - Posted by Anonymous (not verified)

Even Intel will hit the Gigabucks process node wall before the laws of physics put an end to Moore's law/observation, it's costing almost geometrically more with each new process node shrink, so the R&D costs curve verses the ability to amortize these costs over total units sold, is going to rapidly approach the untenable, even for Intel's big wallet. Why do you think Intel is slowing the Tick Tock, well that and some lack of competition in the x86 desktop market. Going below 14nm, and not having a large enough market for its x86 based parts in the mobile market, is making those amortization curves say no, that and Intel's Internal bean counters/quants in the accounting division, and stockholders/investors, and the big institutional investors, that hold Intel's stock(big institutional investors that are accustomed to high dividends at the expense of R&D/whatever, or they will leave for greener pastures).

Intel is coping with an x86 based ISA ecosystem that has hardly any share of the Mobile devices market, and the future licensed Power8s coming in the server market, watch Intel's share price, once Google announces a firm commitment with the Power8 systems that Google is currently evaluating, that along with the ARM server SKUs beginning to arrive, and compete(no worries there for the ARM based server SKU makers) with Intel's Avoton(Discontinued/rebranded). Intel is facing a loss of market domination(more so because of different ISAs, used in mobile, and future high power non x86 ISA competition coming to the server room, along with non high powered ARM based densely packed server SKUs), and the x86 based unit sales, that allowed Intel to spend its way to process node leadership are now stagnating, see the empty chip fab buildings.

Intel's x86 still dominates in the PC/Laptop market, but the ISA that will/continue to dominate the netbook/chromebook, and tablet market is non x86, and comes with better graphics, and Apple, Nvidia, and soon AMD will be introducing more powerful Custom wide order ARMv8 SOCs, with better graphics, the Tegra K1's graphics is the leading example currently, of why Intel will not be able to sell enough of x86 to make the investments in below 14nm process node pay off as quickly as 22nm, or 32nm before that. The entire silicon based economy is rearranging around dedicated foundries providing fab services for the entire industry, and Intel is one of the last CPU manufacturer holdouts that will still be holding its own fab capacity, and the affordable process node lead for even Intel is drying up fast, without the total unit sales to keep those expensive chip fabs (Uber expensive at 14nm and below) running at full capacity. The GPU makers will be getting the most out of 28nm, before they go to 20nm, as the costs to go below will have to be shared by more companies, than just AMD, or Nvidia, to make it cost effective to go below 20nm. Look for more FINFET and die stacking, and less shrinking, going forward.

September 2, 2014 | 01:15 PM - Posted by Lithium (not verified)


missing old Anand

bzzzzZZZ DIE AMD just die frrrrrfrrrr

September 2, 2014 | 08:17 PM - Posted by Anonymous (not verified)

AMD will never die, they will just go 3 ISAs, ARM, x86, and Power8(Rory still has that IBM time under his belt), And SeaMicro(AMD owned) sells Xeon server SKUs, to go along with the Opteron(ARM, and x86 based), and SeaMicro will be selling Power8 based systems too, once those licensed Power8s start hitting the market, Most likely AMD will license the Power8, like the ARM, and profit more than 3 ways. AMD's SeaMicro selling Xeon based Kit! business is funny that way, when that's what the customer wants, and there's money to be made.

September 2, 2014 | 02:45 PM - Posted by ZoA (not verified)

Thanks for the review. I was just looking for a card to upgrade form my old HD7770, this seems like a reasonable choice, good value for the money. But I'm a bit concerned about somewhat poor performance of this card with mantle I've seen in other reviews, hope it is only driver issue that will be resolved. Have you done any testing with mantle?

September 2, 2014 | 03:16 PM - Posted by Anonymous (not verified)

Wait for Nvidia Maxwell GTX 960 in October.

September 2, 2014 | 08:37 PM - Posted by arbiter

well rumors say end of this month if holds true well.

September 3, 2014 | 08:05 AM - Posted by Anonymous (not verified)

Ryan Shrout
You do not know how to ask the right questions

" AMD said that the only the newest GPU silicon from AMD will support FreeSync displays "

" the Hawaii GPU that drives the Radeon R9 290 and 290X will be compatible with FreeSync monitors "

what is compatible ???

September 4, 2014 | 05:43 AM - Posted by Jabbadap (not verified)

All AMD Radeon™ graphics cards in the AMD Radeon™ HD 7000, HD 8000, R7 or R9 Series will support Project FreeSync for video playback and power-saving purposes. The AMD Radeon™ R9 295X2, 290X, R9 290, R7 260X and R7 260 GPUs additionally feature updated display controllers that will support dynamic refresh rates during gaming.
AMD APUs codenamed "Kaveri," "Kabini," "Temash," "Beema" and "Mullins" also feature the necessary hardware capabilities to enable dynamic refresh rates for video playback, gaming and power-saving purposes. All products must be connected to a display that supports DisplayPort Adaptive-Sync.

Tonga will support it too.

September 4, 2014 | 09:26 AM - Posted by 631111

I asked AMD
Customer Service says not support DP 1.2a

Video card can connect to the screen with DP 1.2a
But not working full standard

what is compatible ???
Sit on a chair is compatible

September 3, 2014 | 07:07 PM - Posted by Anonymous (not verified)

What lenovo laptop is that Ryan is using?

September 4, 2014 | 08:03 AM - Posted by Anonymous (not verified)

Inteel make approx 60% margin om chips why eat into that to salve a few noddy enthudiasts wprth at most 100m in sales?
they have tofillcoffer to pay big fines

September 4, 2014 | 06:48 PM - Posted by Anonymous (not verified)

Are you guys gonna test this card in crossfire?

September 5, 2014 | 07:57 PM - Posted by Trevin (not verified)

Ryan don't forget that according to AMD. The R9 280 will have DirectX 12 support and more hardware support for future updates. AMD was implying something more was coming during the interview with ORIGIN PC and AMD.

September 8, 2014 | 05:39 PM - Posted by Anonymous_not t...

Direct X what???

Just sayin.....

Direct X?? lol haha *cough *ahem ahhhhh lol

Edit.. Im happy that Devs are finally gonna START using Dx11. Thx M$, Sony, AMD, x86, and the entire Console Ecosystem as a whole lol. Preciate the love....FINALLY

September 5, 2014 | 08:08 PM - Posted by Trevin (not verified)

Sorry the R9 285 will have DirectX 12 support and more goodies are coming.

September 5, 2014 | 10:03 PM - Posted by Anonymous (not verified)

FreeSync...the Sync that Sunk

September 8, 2014 | 07:10 AM - Posted by lott11

I was wondering if you are thinking of doing a review on AMD R9 285 with 2 cards in XDMA mode.
To compare similar cards in Crossfire and Nvidia SLI, when you get more samples of R9 285.
And when or if there’s going to be any monitors with FreeSync, or at least of any rumors.
Also I seen a few photos of a new AMD Socket & CPU At 5.233 MHz with 6 cores do next year.
6 Mg. L2 and 24 Mg L3 cache & rated at 190 W and thermals at 24 C. and it is not a Piledriver.
Is this just a rummer or is it in the works.

December 2, 2014 | 06:57 PM - Posted by Rock (not verified)

What should I buy R9 270x @ 169.99 or R9 285 $249.99
I play Diablo 3 and I am upgrading from HD 5770 :)

Please help.


April 28, 2015 | 04:26 PM - Posted by Anonymous (not verified)

My R9 285 is constantly dropping GPU core clock and GPU usage when gaming or testing, this is normal?

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Lines and paragraphs break automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd> <blockquote><p><br>
  • Web page addresses and e-mail addresses turn into links automatically.

More information about formatting options

This question is for testing whether you are a human visitor and to prevent automated spam submissions.