Overview AMD Radeon R9 285: worthy replacement GPU Tahiti

Overview AMD Radeon R9 285: worthy replacement GPU Tahiti


    Adapter, which will take place Radeon R9 280, based on a new GPU Tonga, has all the advantages of the second generation architecture GCN: block TrueAudio, CrossFire connection via PCI-E, optimizations for power consumption and performance. Main rival R9 285 – GeForce GTX 760.

    It has been almost a year since the last time AMD has introduced a new GPU for desktop graphics cards – it was Hawaii, which formed the basis Radeon R9 290 and 290X. Today’s launch more modest in scale and is associated with the graphic card, the second tier, counting from the most efficient models.

    AMD already has a large and well-balanced line of discrete graphics cards, so it makes sense to change anything just by replacing individual items fresher iron. Radeon R9 285 replaces the Radeon R9 280, and is known from unofficial sources, soon R9 285X will replace Radeon R9 280X. And although the R9 280 and 280X – quite successful and competitive card, there is a good reason to dismiss them.

    R9 280 and 280X based on GPU Tahiti, which debuted in the Radeon HD 7970 and will soon celebrate its third anniversary. In the line of Radeon Rx 200 Tahiti received a small modification aimed at reducing energy consumption (R9 280X products were quietly transferred to buyers manufacturers to version Tahiti XTL).

    Yet it is the same GPU, which for the first time AMD tried microarchitecture Graphics Core Next and 28 nm process technology. Nearly three years, definitely formed a space for change.

    To date, the model number of AMD GPU present two generations. Most people use the first version of GCN architecture and migrated out of the lineup Radeon HD 7000 with simultaneous renaming of the silicon. Only two graphics processors belong to the updated version of the architecture of GCN, which is informally called GCN 1.1 (although AMD has never used such a classification).

    The latest version of GCN brought a lot of innovations, including an integrated DSP TrueAudio, CrossFire without bridges and a more effective mechanism controlling the frequency and power PowerTune. In addition, gain experience with the 28 nm process technology, AMD has increased the density of transistors on a GPU to the second wave. As a result – more chips per wafer and lower the cost of production.

    Include new GPU in the current model range is also quite reasonable with the expectation that it will be reused in the following family of graphics cards. Chip Tonga, which is based on the Radeon R9 285 (X), will undoubtedly find a place in the line of Radeon Rx 300.

    Finally, we see that Tonga may be something more than GCN 1.1. AMD is not the first time trial run on relatively cheap GPU new features, which are then transferred to a more powerful chips.

    GPU Tonga, specifications Radeon R9 285

    The GPU in Tonga Radeon R9 285 Configuration execution units is fully consistent with the chip in Tahiti Radeon R9 280, and before him – in HD 7950. formula includes 28 active Compute Unit’ov with attitude shader ALU (stream processors, in the terminology of AMD ) to the texture units in the proportion of 16: 1, which gives a total of 1792 stream processors and 112 texture units.

    Peak clock frequency R9 285 and R9 280 also similar: 918 and 933 MHz, respectively, so it is not surprising that the adapters have almost equal to the theoretical performance: 3,29 and 3,3 TFLOPS, respectively.

    Unfortunately, nothing is known about the FP64-speed computing, but for a gaming video card is quite a minor figure. Claimed fillrate R9 285 was even slightly higher than that of R9 280 (102.8 vs. 92.6 Gteks / s), although it is not clear, why would: the number of texture units, then they have the same.

    According to the concept presented in the GPU Hawaii, GPU execution units are distributed among the four largest unified architectural units – Shader Engines. Each of them also has a separate geometry processor, resulting in Tonga is capable of handling four geometric primitives per clock compared to two in Tahiti.

    Tonga also has four times as much – eight – ACE (Asynchronous Compute Engine), which act as planners and dispatchers teams in the GP-GPU-computing.

    A block diagram of Tonga (from unofficial sources) includes 32 CU and 384-bit memory bus into a fully functional version of the chip

    In the rest of the device front-end processors Graphics Core Next architecture has changed little since the days of Radeon HD 7970. Readers wishing to understand how the GCN, or a refresher, refer to the review of the Radeon HD 7970 chip and Tahiti, as well as the Radeon R9 290X.

    Crystal Tonga in the R9 285 uses a 256-bit memory bus, as opposed to the 384-bit bus Tahiti. Even though the bus frequency is increased by 500 MHz compared to that of the Radeon R9 280, interface bandwidth R9 285 can not be less than its predecessor. Accordingly, the amount of memory on the reference specification reduced from 3 to 2 GB. ROP count remains unchanged – 32 pieces.

    Model Radeon R7 280 Radeon R9 280X Radeon R9 285 Radeon R9 290
    Codename Tahiti PRO Tahiti XT2 / Tahiti XTL Tonga PRO Hawaii PRO
    Number of transistors, million 4313 ND 6020
    Process technology, nm 28
    Clock frequency MHz: High State/Boost State 827/933 850/1000 918/- -/947
    Number of stream processors 1792 2048 1792 2560
    Number of texture units 112 128 112 160
    ROPs 32 64
    Bus width, bit 384 256 512
    Chip type GDDR5 SDRAM
    Clock speed: real (effective), MHz 1250 (5000) 1500 (6000) 1375 (5500) 1250 (5000)
    Volume, MB 3072 2048 4096
    I/O bus PCI Express 3.0 x16
    Interfaces (max resolution @ frame rate, Hz) VGA (2048×1536@85), DL DVI (2560×1600@60), HDMI 1.4a (4096×2160@24), DisplayPort 1.2 (4096×2160@60)
    Output ports 1 x DL DVI-D, 1 x DL DVI-I, 1 x DisplayPort, 1 x HDMI 2 x DL DVI-D, 1 x DL DVI-I, 1 x DisplayPort, 1 x HDMI
    TDP, W 200 250 190 250

    The main intrigue around Tonga is whether this is the full configuration. It is logical to assume that the composition of Radeon R9 285 used cut chips, the computing units which locked. Then the upcoming Radeon R9 285X is, apparently, a fully functional crystal, not inferior to the full version of Tahiti. In the end, it is unlikely that the differences between R9 285 and R9 285X limited to clock speeds.

    All this could be done a little more than conclusions, based on the number of transistors on a chip, but this information does not reveal AMD. Is that the power consumption Radeon R9 285 alludes to the chip, not inferior to Tahiti: 190 watts – not much less than the 200 watts Radeon R9 280.

    However, thanks to this new adapter small step closer to energy efficiency to GeForce GTX 760 and GTX 670, which are its main competitors (TDP both is 150 W).

    We measured the chip area Tonga was greater than that of Tahiti: 374,7 mm2 versus 365 mm2. Part of the area is occupied by Tonga blocks XDMA and TrueAudio, missing in Tahiti, but when adjusted for the expected seal the chip, the more likely that the full-featured version of the chip still has a 384-bit memory bus.

    Although energy efficiency AMD still have work to do, the updated version of the mechanism PowerTune, characteristic of the products based on GCN 1.1, is already a good achievement. Recall how the avtorazgon / throttling adapters AMD.

    From a minimum frequency of 300 MHz are measured several steps to 100 MHz, each of which has its own code of voltage GPU (VID). Depending on the load on the GPU PowerTune calculates the power consumption and establishes a pair of frequency / VID, so that the card remains within prescribed TDP and at the same time use this resource to the maximum.

    And since the 100 MHz – this is a very large distance between the steps, they are replaced with a period of 10 ms, forming a kind of average frequency: in the same manner as a controlled cooling fans or LED backlight monitor using PWM. Details of this mechanism is described in our review of the Radeon HD 7790.

    XDMA, True Audio, H.264 codec with support of Ultra HD

    From chips Bonaire and Hawaii, which are the first native architecture GCN 1.1, Tonga borrowed additional components of the processor uncore-absent in GPU Tahiti. First of all it blocks XDMA, allow multiple GPUs to communicate via PCI-E 3.0 instead CFBI (CrossFire Bridge Interconnect – bridges CrossFire).

    CrossFire bridges on maps without guarantees a uniform frame rate, regardless of the resolution, and simply more convenient to set up. Another component of the chip – integrated DSP TrueAudio, intended for sound processing hardware in real time. All this and more in detail in the review of Radeon R9 290X.

    As with other graphics cards based on GPU architecture GCN 1.1 (Series R7 and R9 260 290), Tonga will receive full support FreeSync – under this brand name hides the function interface DisplayPort 1.2a, which provides a variable time refresh (like NVIDIA G-SYNC). In the maps based on the first version of GCN FreeSync will only be used to play videos and to save energy.

    Tonga also has something which is no other GPUs GCN 1.1, – the updated blocks UVD (Unified Video Decoder) and VCE (Video Codec Engine), received support hardware decoding and encoding video in H.264 format with Released Ultra HD. Format H.265 manufacturers are in no hurry to lay in silicon.


    The suggested retail price Radeon R9 285 for the USA market is $ 249. Approximately the same number asking for Radeon R9 280 and GeForce GTX 670. However, if the Radeon R9 285 will not back down in the performance of the line drawn Radeon R9 280, the extra charge for the extra features it is valid.

    SAPPHIRE DUAL-X R9 285 OC: design

    Once again, the new position in the lineup is a Radeon graphics card production SAPPHIRE, modification OC with a little overclocking the GPU and video memory: up to 965 and 5600 MHz, respectively.

    The device is cooled unassuming-looking cooler with two fans of size 85 mm. Radiator fins are penetrated by four heat pipes of different diameters. Some small radiators are installed on the system power transistors.

    On a set of video interfaces and location device repeats the reference design AMD 200 series Rx: port HDMI 1.4a, DisplayPort (apparently, version 1.2a) and two Dual-Link DVI, including the analog output.


    The layout is clearly simplified with the use of 256-bit memory bus and removing connectors CrossFire. The power supply system is arranged according to a 5 + 1 + 1 (the number of phases to power GPU, memory chips and IO interface thereof).

    The controller, power supply ON NCP81022, compatible with dynamic frequency and voltage control GPU in the new version PowerTune, – exactly the same as in the Radeon R7 260 (X) on the chip Bonaire.

    2GB of memory chips recruited Elpida W2032BBBG-6A-F, designed to work in an effective frequency of 6 GHz.

    Testbed, Testing Methodology

    Testbed configuration
    CPU Intel Core i7-3960X @ 4,6 GHz (100×46) Intel Core i7-3970X @ 4,6 GHz (100×46)
    Motherboard ASUS P9X79 Pro
    Memory DDR3 Kingston HyperX 4×2 GB 1600 MHz, CL9
    ROM Intel SSD 520 240 GB
    Power Supply Corsair AX1200i, 1200 W Seasonic Platinum-1000, 1000W
    CPU Cooling Thermalright Archon
    Housing CoolerMaster Test Bench V1.0
    Operating System Windows 7 Ultimate X64 Service Pack 1
    Software GPU AMD AMD Catalyst 14.7 Beta 2
    Software GPU NVIDIA 340.52 WHQL

    Power measurement system used stand with power supply Corsair AX1200i. Energy-saving technologies in all CPU tests disabled. PCI-Express bus operates in 3.0. To activate the PCI-E 3.0 video cards series GeForce 600 and 700 in the X79 chipset applied the patch from NVIDIA.

    In the settings of the NVIDIA driver always as PhysX processor to calculate the selected CPU. In the settings AMD has always Tesselation setting shifted from the state to the AMD Optimized Use application settings. In CrossFire-enabled configurations remains optional Frame Pacing.

    Set of benchmarks
    Program API Settings Anisotropic filtering, anti-aliasing Resolution
    3DMark 2011 DirectX 11 Profile Extreme
    3DMark DirectX 11 Test Fire Strike (not Extreme)
    Unigine Heaven 4 DirectX 11 DirectX 11, max.quality, tessellation in Extreme mode AF 16x, MSAA 4x 1920×1080 / 2560×1440
    DiRT Showdown.Built-in benchmark DirectX 11 Max.Quality, Global Illumination incl.Track Shibuya, 8 cars AF, AA 4 1920×1080 / 2560×1440
    Far Cry 3 + FRAPS DirectX 11 DirectX 11, max.quality, HDAO.Starting mission Secure the Outpost AF, MSAA 4x 1920×1080 / 2560×1440
    Tomb Raider.Built-in benchmark DirectX 11 Max.quality AF 16x, SSAA 4x 1920×1080 / 2560×1440
    Bioshock Infinite.Built-in benchmark DirectX 11 Max.quality.Postprocessing: Normal AF 16x, FXAA 1920×1080 / 2560×1440
    Crysis 3 + FRAPS DirectX 11 Max.quality.Start Time Post Human AF 16x, MSAA 4x 1920×1080 / 2560×1440
    Metro: Last Light.Built-in benchmark DirectX 11 Max.quality AF 16x, SSAA 4x 1920×1080 / 2560×1440
    Company of Heroes 2. Built benchmark DirectX 11 Max.quality AF, SSAA 4x 1920×1080 / 2560×1440
    Batman: Arkham Origins.Built-in benchmark DirectX 11 Max.quality AF, MSAA 4x 1920×1080 / 2560×1440
    Battlefield 4 + FRAPS DirectX 11 Max.quality.Starting mission Tashgar AF 16x, MSAA 4x + FXAA 1920×1080 / 2560×1440
    Thief.Built-in benchmark DirectX 11 Max.quality AF 16x, SSAA 4x + FXAA 1920×1080 / 2560×1440

    Test participants

    In performance testing included the following video cards:

    • AMD Radeon R9 285 (918/5500 MHz 2 GB)
    • AMD Radeon R9 280X (1050/6000 MHz, 3GB)
    • AMD Radeon R9 280 (933/5500 MHz, 3GB)
    • AMD Radeon R9 270X (1050/4800 MHz, 2 GB)
    • NVIDIA GeForce GTX 770 (1046/7012 MHz, 2 GB)
    • NVIDIA GeForce GTX 670 (915/6008 MHz, 2 GB)
    • NVIDIA GeForce GTX 760 (980/6008 MHz, 2 GB)

    Overclocking, temperature, power consumption

    Acceleration Radeon R9 285 in the same way as in other models architecture GCN 1.1 and the new version PowerTune. This panel Catalyst Control Center gives you the hands of overclocker three tools: frequency control GPU, power limiters, and fan speed. Separately regulated memory frequency. GPU voltage changes dynamically and is not available as in the CCC, as well as through third-party utilities.

    During normal operation, the voltage under load reaches 1,163 V. Tonga satisfied with the Voltage significantly smaller compared to Tahiti as part of Radeon R9 280, which corresponds to the upper VID voltage 1,237 V.

    Assigned map SAPPHIRE limit fan speed – 50% of the maximum – more than enough to rate even under heavy load fluctuated around the upper limit of the range of PowerTune. At the same fan speed in absolute value is small, and therefore – and noise.

    VGA BIOS gives you the opportunity to raise the upper limit of the frequency up to 1150 MHz. As we know from experience, for many graphics cards based on Tahiti, the overclocking is not a problem.

    From SAPHHIRE DUAL-X R9 285 OC we were able to achieve stable operation only at a frequency of 1100 MHz, but it is compared to the nominal frequency of 965 MHz can be considered a successful outcome. Graphics memory is overclocked to 6.6 GHz effective frequency – 1 GHz higher than normal values.

    At peak power Radeon R9 R9 285 and 280 is not particularly different from each other. But perhaps, the differences are manifested in the average energy consumption. For GeForce GTX 760 NEW obviously can not compete in terms of energy efficiency.

    Cooling System video SAPPHIRE effective enough to keep the GPU temperature under load within 63 ° C.

    Performance: Synthetic Tests

    3DMark 2011

    • Radeon R9 285 has a slight advantage over its predecessor, the Radeon R9 280.
    • Novelty is also perfectly adapted to the performance of GeForce GTX 760. GTX 670 is located above a small margin.


    • As well as in 3DMark 2011, a new synthetic test Radeon R9 285 got a much higher score than the Radeon R9 280.
    • From a competing team R9 285 left behind not only the GeForce GTX 760 and GTX 670 but even on the heels of GTX 770.

    Unigine Heaven 4

    • Again R9 285 takes precedence over R9 280, more pronounced at a resolution of 1920×1080. Increased productivity affects the geometric engine. At a resolution of WQHD 384-bit memory bus R9 280 smooths the differences between the two cards.
    • Radeon R9 285 also successfully cope with the GeForce GTX 760 and reached parity with the GTX 670.

    Performance: gaming tests

    DiRT Showdown

    • The differences between the Radeon R9 285 and R9 280 compensate each other, so that the results are almost identical adapters.
    • DiRT Showdown has always been the most comfortable test for GPU AMD in our test clip. So this time Radeon R9 285 had left behind all three video cards NVIDIA, including the GeForce GTX 770.

    Far Cry 3

    • Radeon R9 285 and R9 280 do not differ from each other in this test.
    • Both are equally inferior graphics cards NVIDIA, although the absolute value of the difference between them and the nearest competitor – GeForce GTX 760 – is quite small.

    Tomb Raider

    • Again, we can say that R9 285 is virtually identical to R9 280, symbolic despite lag mode WQHD.
    • Equally – symbolically – gives new GeForce GTX 760.

    Bioshock Infinite

    • Results Radeon R9 280 and R9 285 are virtually indistinguishable.
    • Both AMD cards significantly outperform GeForce GTX 760, and a symbolic value of – GTX 670.

    Crysis 3

    • Radeon R9 280 and R9 285 are equal.
    • Approximately the same performance has GeForce GTX 760.

    Metro: Last Light

    • Compared Radeon R9 280 and R9 285 is a tiny advantage in favor of the latter.
    • R9 285 is clearly superior to GeForce GTX 760 and even on par with the GTX 770 at a resolution of 2560×1440.

    Company of Heroes 2

    • This test does not distinguish between the Radeon R9 285 and Radeon R9 280.
    • GPU NVIDIA work in CoH 2 is not as effective as the products of AMD. It is not surprising that the Radeon R9 285 left behind as the GeForce GTX 760, GTX 670 and and stands on a par with the GTX 770.

    Batman: Arkham Origins

    • This game, on the contrary, favorable to the GPU NVIDIA. Radeon R9 285 as Radeon R9 280, a small amount, but still inferior to GeForce GTX 760.
    • Virtually no significant difference between the two adapters AMD is not found.

    Battlefield 4

    • Radeon R9 285, Radeon R9 280 and GeForce GTX 760 have almost the same performance in Battlefield 4.


    • In Thief difference between Radeon R9 285 and R9 280 is greatest. Newbie significantly outperforms its predecessor, and even a hair walked Radeon R9 280X, taking the lead. Apparently, the engine Thief stronger than the other games in our testing, load geometric blocks GPU.
    • Equal to the Radeon R9 285 performance in the team has NVIDIA GeForce GTX 770. only the GTX 760, GTX 670 and provided a much lower frame rate.

    Performance: overclocking

    3DMark 2011

    • The rise of the GPU frequency to 182 MHz vividly reflected in the scores of both versions of 3DMark.

    Game tests + Unigine Heaven 4

    • In games, the effect of overclocking is not as great as in synthetics. The difference is noticeable only at high absolute values ​​of frame rate.


    Despite the 256-bit memory bus, Radeon R9 285 was a full replacement Radeon R9 280. In most games, a beginner at least not inferior to its predecessor, and in some cases significantly surpasses its performance. These advances are likely, is attributed to a more powerful engine, geometric processor Tonga.

    In addition, Tonga provides a complete set of additional functions, which acquired GPU based on Graphics Core Next architecture since the release of the chip Tahiti: TrueAudio, CrossFire by DMA, support Adaptive Sync interface DisplayPort 1.2a.

    We can not ignore the energy optimization, which have chips generation GCN 1.1. Tonga also accelerates thumbs up, although it is not a strong effect on the frame rate in the heavy graphics mode (which is quite a novelty on the shoulder of the test in many games).

    The main contenders – GeForce GTX 760 and Radeon R9 285 – the performance is almost equivalent, if we exclude the tests, particularly favorable for a particular manufacturer. They are also quite similar prices, so choosing anything from this pair, it will be difficult to miscalculate.

    Is that part of the energy GTX 760 has a distinct advantage. How are AMD, and NVIDIA’s products have acquired a certain similarity ecosystems, and the choice will ultimately depend on the habits and preferences of the user.

    [easyazon_block add_to_cart=”default” align=”right” asin=”B00N2ROPEA” cloaking=”no” layout=”top” localization=”default” locale=”US” nofollow=”default” new_window=”default” tag=”gadgethelp-20″]In general, the change of chip Tahiti to Tonga in this segment of the discrete graphics cards AMD is successful and did not require any compromises. Radeon R9 285 R9 280 is a little expensive, and besides, the stores will get rid of the stocks of the outgoing model to rest at a discounted price, so that those who are going to buy an adapter in this price range and does not need TrueAudio and other additions architecture GCN 1.1, yield R9 285 still benefit.

    But note that the Radeon R9 285X, the launch of which is also not far off, purely from a technological point of view is more interesting product, as soon as he will answer the question: Is the GPU Tonga composed Radeon R9 285 is a simplified version?

    If the chip is in full configuration will not give Tahiti by number of execution units and memory bandwidth, and in addition will optimize the architecture GCN 1.1, this is clearly exacerbate competition among high-performance graphics cards of the second tier. Soon we will find out it was true or not.

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