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ATI's Radeon X1650 XT graphics card


Trick or treat?
— 5:00 AM on October 30, 2006

DON'T LET THE Radeon X1650 XT's name fool you. Although the amalgamation of letters and numbers behind "Radeon" might lead you to believe this card is a direct heir of the notoriously poky Radeon X1600 XT, this puppy is much more potent than its predecessor. In fact, its GPU is more like two X1600 XTs fused together, with roughly twice the graphics processing power in nearly every meaningful sense. The X1650 XT has 24 pixel shader processors instead of 12; it has eight texturing units rather than four; and it can draw a healthy ocho pixels per clock, not just an anemic cuatro like the X1600 XT before it.

Those numbers may be the recipe for success for the Radeon X1650 XT, making it a worthy rival of the GeForce 7600 GT at around $149. If so, this product arrives not a second too soon. It seems like ATI hasn't had a credible offering in this segment of the market since hooded flannel shirts were all the rage. Can the Radeon X1650 XT break the red team's mid-range curse? Let's have a look.


The Radeon X1650 XT

Meet the wild child
The Radeon X1650 XT's unassuming appearance conceals its true personality. Under that pedestrian single-slot cooler lies a wildly transgressive graphics card, driven by a GPU that refuses to honor the boundaries of class or convention. The X1650 XT is part of the Radeon X1600 series, yet its graphics processor is not the RV530 silicon that has traditionally powered cards in that product line. The intrigue gets even deeper when you examine this mysterious GPU, code-named RV560. Truth be told, this is actually the same graphics chip behind the Radeon X1950 Pro that we reviewed a couple of weeks ago, the R570. For the X1650 XT, though, ATI has disabled portions of the chip and assigned it a new code name. If I recall correctly, this is the first time ATI has fabricated two code names for the same piece of silicon. So basically, ATI has chucked the conventions for both video card names and GPU code names in recent weeks, and the Radeon X1650 XT is the result.

Not that there's anything wrong with that.

In fact, the X1650 XT benefits from its upper-middle-class heritage. Its RV570 GPU (sorry, but I'm not calling it RV560) has had a portion of its on-chip resources deactivated, either because of faults in some parts of the chip or simply for the sake of product segmentation. This hobbled GPU can still take on the GeForce 7600 GT with its one good arm, though, thanks to 24 working pixel shaders, eight vertex shaders, and eight texture units/render back-ends. These rendering bits and pieces run at a GPU core clock of 575MHz. To keep card costs down, the Radeon X1650 XT has only a 128-bit path to memory (like the GeForce 7600 GT) and not 256 bits (like its big brother, the X1950 Pro.) The X1650 XT's 256MB of GDDR3 RAM runs at 675MHz.


Dual dual-link DVI ports flank the X1650 XT's TV-out port

The X1650 XT's cluster of ports befits a brand-new graphics card. The two dual-link DVI ports come with full support for HDCP, so they can participate in the copy-protection schemes used by the latest high-def displays.

If you're driving a big display at high res with an X1650 XT, you may want to give it some help in the form of additional X1650 XT cards that run alongside it. That's a distinct possibility thanks to the pair of internal CrossFire connectors on the top edge of the card. We've tested the X1650 XT in a dual-card CrossFire config, and ATI has confirmed for us that they plan to enable support for more than two cards in CrossFire using staggered connectors at some point in the future, although we don't know much more than that.

That's pretty much it for the Radeon X1650 XT's basic specifications. Of course, it's based on very familiar Radeon X1000-series GPU technology, with features and image quality that match everything up to the Radeon X1950 XTX. ATI says to expect cards at online retailers the week of November 13. The big remaining question is performance.