Posted 08/03/09 at 09:00:00 AM by Will Smith

It’s no secret that ATI’s RV770 GPU, which first appeared in the Radeon 4870 and 4850 last year, is a performance beast. The spring refresh of the GPU, which offers increased core and memory clocks, along with a slight redesign of the GPU, tells an interesting story to anyone who isn’t yet running a second-gen DirectX 10 card (GeForce 2xx series or Radeon 48xx series). However, if you’ve already upgraded, there’s not much to get excited about here.

The Radeon 4890 is built on a 55nm process, just like the 4870 and 4850, but the company made significant tweaks to the architecture to accommodate higher clock speeds, which is evidenced by the fact that Diamond overclocks this board from 850MHz to 925MHz out of the box. Diamond also overclocks the card’s 1GB of memory 100MHz faster than the default, to 1,050MHz. The Radeon 4890 sports quad-pumped GDDR5 memory running on a 256-bit bus. The real stars of the Radeon 4890’s show are its pixel shaders, though, with 800 shader units running at the GPU’s core clock speed. The massive number of shader units gives the 4890 a significant advantage over comparable Nvidia cards in shader-limited benchmarks like Crysis.

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Posted 07/23/09 at 09:30:00 AM by Michael Brown

We’re constantly on the hunt for top-shelf PC performance—you’re not reading Bottom-Feeder PC, after all. When rendering our review verdicts, we do factor in price, but recommending a subpar product just because it’s cheap is sacrilege to us. Pricing can be relevant, but when it comes to videocards, we typically anchor our opinions on the toughest criteria we know of: 3D performance in the most demanding games on the market, at resolutions of 1920x1200 and higher and with all eye candy enabled.
 
While our editorial mantra might best be expressed as “better, faster, stronger” (hey, we should do a cover story on that!), there’s no escaping the fact that the videocard market boasts a broad spectrum of inexpensive—and intriguing—alternatives. In fact, as AMD and Nvidia have been battling for supremacy at the top of the market, we’ve watched the entry points for penultimate-performance videocards gradually but consistently come down to earth. Sure, playing Crysis on a 30-inch panel might be out of the question if you’re running one of the lower-priced cards, but we still wanted to discover the 3D tipping point—the point at which you’re better off giving up PC gaming altogether because the card you’re running is horribly, utterly lacking in horsepower.

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Posted 07/22/09 at 10:35:00 PM by Michael Brown

The Radeon HD 4830 at the heart of this card is a cut-down version of AMD’s second-best graphics processor, the RV770. The 4830 has 640 stream processors, compared to the 800 processors in a higher-end card such as the Radeon HD 4870.

The 4830 is designed to run at slower clock speeds, too, and PowerColor sets this model to operate its core at 575MHz and its 512MB of GDDR3 memory at 900MHz. These are pretty hobbled specs compared to those of the reference-design Radeon HD 4870, which boasts core and memory clock rates of 780MHz and 1GHz, respectively.

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Posted 07/22/09 at 10:34:00 PM by Michael Brown

Whereas AMD’s Radeon HD 4830 resembles a Radeon 4870 after a partial lobotomy, the Radeon HD 4850 that sits between these two cards comes with a full complement of 800 stream processors. But don’t make the mistake of thinking you can overclock a 4850 board to achieve the same performance as one based on the 4870: The latter uses GDDR5 memory while the former is limited to GDDR3.

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Posted 07/22/09 at 10:33:00 PM by Michael Brown

Nvidia’s GeForce 9800 GT is really just a rebadged GeForce 8800 GT, which makes it the only card in our roundup based on a previous-generation GPU architecture: Nvidia’s 65nm G92. Despite its age, however, the G92 helped EVGA’s GeForce 9800 GT best PowerColor’s Radeon HD 4830—at least in terms of gaming performance.

EVGA runs the 9800 GT’s core at 600MHz, but takes full advantage of its 112 shader processors’ capacity for operating at much higher frequencies: 1,500MHz in this implementation. The card has a 256-bit memory interface to a full gigabyte of GDDR3 memory running at 900MHz.

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Posted 07/22/09 at 10:31:00 PM by Michael Brown

The 55nm RV770 is one of the best arrows in AMD’s GPU quiver, so it’s a good thing the part has proven to be both versatile and powerful. As deployed in the Radeon HD 4870, the RV770 has a full complement of 800 stream processors—just like the Radeon HD 4850—but in this design, the GPU is paired with GDDR5 memory.

GDDR5 memory boasts a very high data rate (ranging from 3.6Gb/s to 6.0Gb/s, compared to GDDR3’s 1.0Gb/s to 2GB/s). This enables AMD to deliver nearly the same memory bandwidth through a relatively narrow and inexpensive 256-bit bus as it would with a much wider and costlier 512-bit bus.

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Posted 07/22/09 at 10:30:00 PM by Michael Brown

Nvidia pretty much owns the top end of the GPU market, thanks to the mighty, dual-GPU GeForce GTX 295. But no manufacturer can survive by selling low-volume parts, no matter how pricey they may be. Selling oodles of moderately priced products is where the real money is made. And that’s where the GeForce GTX 275 comes in.

Nvidia would never have concocted the GTX 275 had AMD not launched the Radeon HD 4890. Competition is the consumer’s friend.

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Posted 07/16/09 at 11:45:52 AM by Will Smith

The videocard industry typically works on an 18-month cycle for each GPU design. Last year, Nvidia released the GT200 and ATI launched the RV770. Both are speedy, DirectX 10-capable parts, packed with shader processing power and capable of running the most demanding games at top speed. We tested Nvidia’s first refresh of the GT200 last month (the GeForce GTX 285); now it’s time to put ATI’s first re-spin of RV770 under the microscope, with Asus’s Radeon EAH4890 TOP.

The 4890’s RV790 GPU is built on a 55nm process, just like its predecessors; however, ATI made fairly significant tweaks to the GPU’s structure in order to accommodate higher clock speeds. Asus’s stock overclock is a testament to that revamp. The Asus board’s stock clock is 900MHz (the default stock clock for 4890 boards is 850MHz). Likewise, the board’s quad-pumped GDDR5 memory sits on the same 256-bit bus but runs at 1,000MHz (the stock speed for 4890 boards is 950MHz). The star of the Radeon 4890’s show remains the GPU’s 800 shader units, which handle the heavy lifting in shader-heavy modern games, such as Crysis.

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