ATI Radeon HD 4890: Playing To Win Or Played Again?

Building A Radeon HD 4890

Architecturally, the RV790 graphics processor is identical to RV770. The vital specs haven’t changed one bit. It’s still a 55 nm component, though transistor count is up just slightly to approximately 959 million transistors (from 956 million). The GPU is still made up of 800 stream processors, 40 texture units, and 16 ROPs. It still sports a 1 GB GDDR5 frame buffer on a 256-bit memory bus, too.

Where it differs most is clock speed—on its core and memory bus. Stock Radeon HD 4870s employed a 750 MHz engine and quad data rate memory running at 900 MHz. This new offering cruises at 850 MHz with 975 MHz GDDR5 memory.

In order to get those elevated frequencies, ATI had to do some work to the GPU’s core. In short, the RV770 consistently had issues clocking beyond a certain point—a fact that was evident in many of our System Builder Marathon overclocking attempts, which generally fell short at the same frequency range.

The company’s engineers went in looking for slow electrical paths and re-wired them in such a way that they wouldn’t inhibit faster frequencies. Physically, the GPU is fractions of a millimeter larger due to additional capacitors that clean up power to the chip. But it remains the same ol’ design popularized mid-2008. As you can see from the table above, clock-for-clock RV770 and RV790 perform nearly-identically clock-for-clock.

Radeon HD 4870 X2
Radeon HD 4890Radeon HD 4870
GeForce GTX 285
GeForce GTX 260 Core 216
Manufacturing Process55 nm TSMC55 nm TSMC55 nm TSMC55 nm TSMC55 nm TSMC
SPs1,600 (2 x 800)
Core Clock750 MHz850 MHz
750 MHz648 MHz
576 MHz
Shader Clock750 MHz850 MHz750 MHz1,476 MHz
1,242 MHz
Memory Clock900 MHz GDDR5
975 MHz GDDR5
900 MHz GDDR51,242 MHz GDDR3
999 MHz GDDR3
Frame Buffer2 x 1 GB
1 GB
1 GB / 512 MB
1 GB
896 MB
Memory Bus Width2 x 256-bit
ROPs2 x 16

Not surprisingly, the 4890 card itself is easily mistaken for a Radeon HD 4870. They’re the same length; they both employ dual-slot coolers and the same dual-DVI plus video output configuration. Subtle differences set the two cards apart, giving away the fact that these two boards are indeed based on different GPUs.  And despite the slight increase in load power consumption as a result of the 4890’s higher clock speed, ATI still gets away arming the card with two six-pin auxiliary power connectors.

As of right now, ATI doesn’t have plans for a Radeon HD 4890 X2 variant, as it likely wouldn’t offer much more than a Radeon HD 4870 X2. And the chip’s extra full-load power consumption would create additional heat that’d need to be cooled.


The principal benefit from moving from HD 4870 to HD 4890 would, in our minds, be overclocking headroom. Stock-to-stock, you’re looking at a 100 MHz frequency increase. However, right out of the gate, ATI’s board partners will be shipping juiced models running a 50 MHz-faster core clock. According to AMD, the new GPU layout should be capable of going even faster than that.

The driver’s Overdrive sub-routine now offers a maximum frequency of 1 GHz, suggesting ATI is fairly comfortable with its enthusiast customers running at that speed. Rather than push our card that high and run the risk of misrepresenting performance with a hand-picked sample, however, we ran our HIS Radeon HD 4890 Turbo sample at its stock 900/975 MHz speeds and compared it to the reference clocks ATI is officially launching.

Upping the core clocks to 900 MHz is good for gains between five and 10% at 2560x1600. One of these factory-overclocked boards undoubtedly enhances the value of ATI’s Radeon HD 4890 versus the 4870 1 GB. However, there will undoubtedly be an additional price premium over the reference cards, too, softening the worth of that extra performance to some degree.

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  • skeptic_27
    Where are the HD4890 OC benchmarks, because that is where this card was made for.
  • mi1ez
  • Anonymous
    afaik far cry 2 has nothing to do with crytek anymore but was developed by ubisoft who bought the license
  • Anonymous
    Why aren't there any X3 Terran Conflict benchmarks?
    Surely one of the most power demanding games ever should be a benchmark to show us how these cards react to realkly demanding games.
  • wild9
    With prices on GeForce GTX 260 Core 216s hovering between $180 and $190 online (with rebates dropping that to $160 in many cases), this isn’t June of 2008, where a surprise attack from ATI rocks Nvidia’s world.

    Cheapest I have seen a GTX260 in the UK is £181.00 or $266.00. Forget rebates as well, they're non-existent.

    We're paying an increase of around 66% more and I think that's disgraceful. It's holding the industry back, denying people access to new technology and ripping people off who can barely afford it. Looks like globalisation doesn't extend to harmonising graphics cards specs or prices. Thus, the UK consumer has no choice but to go back to June 2008 or earlier in order to get a graphics card they can afford.

    I am sorry to go, it's just that I would very much like to have access to this technology (nVidia or AMD), and I realise there are different tariffs to take into consideration but this is simply ridiculous. These prices are bound to come down in the US and even before they do they are drastically cheaper than those in the UK. Short, sharp shaft again.
  • tstebbens

    Amazon have the GTX 260 for ~£150. That's still $220 I know, but better than £181. I did find it for as little as £139 but, unsurprisingly it was out of stock.
  • waxdart
    @Wild9 - Blame the government! You’ll just get told - The cost of just doing business in the UK is a lot higher. Also the exchange rates are crap for us right now. And E.U. Law blar blar - and trade agreement- blar blar.

    @ everyone in the UK
    People have been bending over and taking it for far too long. Down with rip-off Britain. Write to your MP. I'll do it too. everyone join in!
  • Reynod
    This article like the previous is a bit too pro NVidia for my liking.

    The ATI cards just waste the current NVidia cards and the X2's are awesome.

    The respin of the 4870 core also allows for much higher overclocking due to the changes to the timings in the core.

    I'd like to see what XFX and some of the others are going to do wit hthis little baby .... expect bigger things than the standard benchies your showing.

    Reviews on a number of other sites are showing the ATI cards in a much more favourable light than here today ...

    Balance ...
  • wild9
    I like the fact that AMD is rolling in GDDR5, instead of sticking to slower, older memory like GDD3. if only AMD could produce a chipset with say, 256MB of the stuff dedicated to the IGP :)
  • wild9
    GDD3..I meant GDDR3, sorry.
  • robbins
    tstebbens that's the old 260.
    You can get the old one for ~ £130

    This is by far the best core 216 to get. £151, factory overclocked, 2 fans... Just ordered one.
  • t-track
    The article is comparing a ATI's 4890 with Nvidia's 260 and 285 by using a driver for the new 4890 that actually does not support fully this card and a well updated and well tested driver for the Nvidia's counterparts.

    That is why the conclusions about the cards' performance are ill founded.

    Wait until the release of the new catalyst 9.4 and you will see that 4890 does not only kill NV 280, but also NV285 at this price range.
  • yourma2000
    this benchmark needs to be retaken with the 9.4 drivers which officially support the 4890
  • Anonymous
    Lawl, vantage.. Vantage counts PhysX support, so you gave nVidia a lead in the synthetic benchies already, and guess what, the 4870 still matches the 285... Let alone what the core update'll do on the 4890. Besides that, like many people before me: Use the damn supportive drivers, then get a bench.