Verdict: Solid performance in current games, but cutting-edge titles trip up the X1900-series.

The X1900-series was launched just three months after the X1800-series, much to the annoyance of ATi fans, who had coughed up top-dollar prices to get ATi's first Shader Model 3 GPU when it launched. The X1900-series was much better than the X1800-series, however, and was designed to take on the GeForce 7900 GTX.

The high-end X1900XTX and X1900XT cards debuted in early 2006, although ATi eventually launched several lower-priced models, all of which are still available.

As the X1900-series is broadly based on the same architecture as the X1800-series, it supports DirectX 9c, Shader Model 3 and HDR lighting with anti-aliasing. However, the big change with the X1900-series is that it has many more pixel processors than texture processors and ROPs. For example, the X1900 All-in-Wonder, X1900XT and X1900XTX all have 48 pixel processors, but only 16 texture processors and ROPs. Even the cut-down X1900GT has 36 pixel processors.

ATi's reasoning behind this is that it believed (and still does) that future games will rely more on shader processing power than texturing performance and fill rate. This was a good bet, as many games, particularly recent titles such as The Elder Scrolls IV: Oblivion, require masses of shader horsepower.

The X1900-series also features a ring bus memory controller similar to that of the X1800-series, which is made up of eight 32-bit channels. This is more efficient than the four 64-bit channels of the X800GTO2. With a redesigned shader core the X1900-series can handle processing tasks other than playing games, such as Folding@home.

The only difference between the X1900XT and X1900XTX is the clock speed. Both cards are equipped with 512MB of GDDR3 RAM, which runs at 725MHz (1.45GHz effective) on the X1900XT, and 775MHz (1.5GHz effective) on the X1900XTX. The GPUs run at 625MHz and 650MHz respectively. This small difference in clock speed means that the X1900XT and X1900XTX perform almost identically. Both cards were capable of playing F.E.A.R. and Need for Speed: Carbon smoothly at 1,680 x 1,050 with some AA and AF, but they struggled with S.T.A.L.K.E.R., which was playable only at 1,024 x 768. Both cards are fitted with the same very noisy HSF, and work in CrossFire only if you buy a dedicated (and more expensive) Master card.

The X1900 All-in-Wonder is the media PC model of the X1900-series and, as such, it includes a digital TV tuner and is bundled with PVR software, a remote control, and multiple video inputs and outputs. Although it has the same GPU as that of the X1900XT and X1900XTX, it's clocked at just 500MHz, and also has just 256MB of GDDR3 clocked at 480MHz (980MHz effective). Due to its lower specifications, the X1900 All-in-Wonder was only able to play Need for Speed: Carbon smoothly at 1,280 x 1,024 with 2x AA and AF enabled, and F.E.A.R. at 1,680 x 1,050 with 2x AA and 8x AF, while S.T.A.L.K.E.R. wasn't even playable at 1,024 x 768. As such, despite the X1900 All-in-Wonder's price more than halving over the past year, you'd be better off buying a dedicated TV tuner and separate gaming graphics card.

The X1900GT was the last of the X1900-series GPUs to see the light of day, and was positioned as a lower-priced, mid-range model. With fewer pixel processors than other models in the series, a lower GPU frequency (512MHz) and 256MB of GDDR3 RAM running at 655MHz (1.31GHz effective), the X1900GT performs considerably worse than its higher-specified siblings. For example, while it was able to play F.E.A.R. smoothly at 1,680 x 1,050 with 2x AA and 8x AF, it couldn't manage S.T.A.L.K.E.R. at all, and Need for Speed: Carbon was playable at only 1,280 x 1,024 with 2x AA and AF enabled. Until a couple of months ago, the X1900GT was still in production, which meant that it was available for a bargaintastic £108, but with stock running out, the price of the few remaining cards has jumped up to £145 or more. As such, we can no longer recommend buying the X1900GT despite its X1900-series credentials.

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