Radeon HD 2600 XT is the new mid-range video card from AMD/ATI, supporting Shader 4.0 unified architecture (i.e. DirectX 10) and competing directly with GeForce 8600 GT from nVidia, both costing around USD 150. In this review we will compare Radeon HD 2600 XT to GeForce 8600 GT and also to several other mid-range boards from both ATI and nVidia. Check it out.

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Figure 1: AMD reference model for ATI Radeon HD 2600 XT.

The main difference between Radeon X1000 and the new Radeon HD 2000 families is the adoption of DirectX 10 on Radeon HD 2000 family. What this means is that they will support the next generation of games to be released starting this year. It also means that instead of using separated shader units for each kind of shader processing (pixel, vertex, physics and geometry) video cards from this family use a unified shader architecture, where the shader engines can process any one of these tasks. On nVidia side, this unified architecture is used on GeForce 8 family – of course implemented differently inside the chip. On our ATI Radeon HD 2000 Series Architecture article you can find a more in-depth explanation about this.

There are two big problems with Radeon HD 2600 XT – and, for that matter, also with other members of the Radeon HD 2600 and HD 2400 families.

First, it isn’t available on the market yet. During AMD’s technical sessions to present Radeon HD 2000 to the media in April, they said that Radeon HD 2600 and Radeon HD 2400 would be available in late June. All we got was a paper launch on June 28th, 2007 announcing the two families, however we are already in July and no sign of these cards on the market. Unfortunately this is an old habit from ATI that AMD still couldn’t get rid off yet. According to AMD, Radeon HD 2600 XT will reach the market 2 weeks after its paper launch, so if everything goes fine we should see this video card on the stores by the end of the next week.

The second problem is that AMD there are two basic versions of Radeon HD 2600 XT, one using GDDR4 memories running at 2.2 GHz (1.1 GHz DDR) and another using GDDR3 memories running at 1.6 GHz (800 MHz DDR). And for Radeon HD 2400 they allow the manufacturer to set any clock rate they want. The problem is that the reference models we got for reviewing were running at the top clock speeds and other Radeon HD 2600 and HD 2400 boards you will find at the market may be running at lower clock rates and thus achieving a lower performance.

We think this is really nasty to the customer, as customers can be easily deceived. One can buy a Radeon HD 2600 XT card based on a review to discover later that the model he or she bought has a performance lower than the model featured on the review, for example.

We think that in name of transparency AMD should require all their partners to add some extra info on the product name to clarify what clocks and/or memory technology that particular product is using, for example Radeon HD 2600 XT xxx/yyy, where xxx is the chip clock and yyy is the memory clock. Or even use a different product name (e.g. 2600 XT for the model with GDDR3 and 2610 XT for the model with GDDR4). But of course we don’t live on a perfect world.

And another thing that is confusing is the future of ATI brand itself. All ATI employees are now officially AMD employees, the website is from AMD, AMD refers ATI products as being AMD products but they are still red and using ATI stickers.

On the Radeon HD 2600 XT reference board we got for reviewing the graphics chip was running at 800 MHz and had 256 MB GDDR4 memory chips running at 2.2 GHz (1.1 GHz x 2), using a 128-bit memory interface. This provides a maximum theoretical memory transfer rate of 35.20 GB/s. Here we must explain that both ATI and nVidia are now referring to their memory clocks with their correct clock rates, not the doubled clock rate – DDR and similar memory technologies work transferring two data per clock cycle and usually their clock rates are labeled with double their real clock rates. In order to make it easier to compare current products to older ones, we are keeping the old way to label memory clock rates.

As we mentioned, the suggested price for this video card is of USD 150, the same price range GeForce 8600 GT currently has. Another question is whether Radeon HD 2600 XT will really reach the market costing that. From our experience the prices of all products rise when they are launched, dropping after some weeks.

For a full comparison between Radeon HD 2600 XT and other chips from ATI, please read our tutorial ATI Chips Comparison Table. On nVidia Chips Comparison Table you can compare them to competitors from nVidia.

On Figures 2 and 3 you can see the reviewed reference model from AMD/ATI.

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Figure 2: AMD reference model for ATI Radeon HD 2600 XT.

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Figure 3: AMD reference model for ATI Radeon HD 2600 XT, back view.