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Radeon HD 2600 Pro &  XT

The HD 2600 series is probably what you guys will buy the most. It's again a fully DX 10 ready product and can do everything the 2400 series can, yet a tad better and faster. Full 1080P HD decoding? Not an issue, seriously not an issue at all! We see the Avivo HD technology for hardware HD video processing with 5.1 audio over HDMI. We'll explain this a bit better in the coming pages. Here's also where the Crossfire fun starts. Have a look at some photos and you'll see the new recently introduced Crossfire connectors (bridged just like NVIDIA's SLI connector). You insert two of these cards in a compatible mainboard, apply the two Crossfire bridges, enable it in the Catalyst driver and you are home-free.

The Radeon HD 2600 series will again be released in a two fold series again each with several configurations, a Pro and an XT version with each in that series containing submodels with 256 and 512MB configurations.

The GPU core has 390 million transistors, which is a friggin lot for a mid-range product. We see a good number of shader processors; 120 Stream Processing Units. From the numbers the cards look very interesting. Clock speeds are high, very high. The Pro is to be clocked at 600 MHz and that XT at an amazing 800 MHz. Now among board-partners and models this can and will vary a little. But again 800 MHz for a mainstream graphics card with such a large number of transistors is an all new record by itself.

As mentioned in a previous chart, there will also be a Gemini version of the XT model. We're a bit unsure what it entails, but I can say with certainty that it is either a Crossfire package or dual-gpu based card as when you look up the word Gemini in the dictionary, you find the following:

• A constellation in the Northern Hemisphere containing the stars Castor and Pollux. Also called Twins.
• The third sign of the zodiac in astrology. Also called Twins.

The memory then. I was really hoping to see AMD be the first to go for a 256-bit wide memory bus but unfortunately just like the competition they are sticking to 128-bit. This is where the cards will hurt from the most.

Configurations will differ, but you'll see 256Mb models based on DDR2, GDDR3 and even a GDDR4 memory. That memory will be clocked at roughly 400 MHz for the Pro up to 1100 MHz for the XT models. Talk about a big difference. I tell you though, the XT is going to be interesting. Prices for the Pro will likely be set at a 99-129 USD pricetag with the XT somewhere at 179-199 USD.

However these are manufacturer suggested retail prices, a week before writing this article at an online shop:

Radeon HD 2600 series:

• Radeon HD 2600XT 512 MB DDR4 PCI-e DVI TV out 179,00
• Radeon HD 2600XT 256 MB DDR4 PCI-e DVI TV out 149,00
• Radeon HD 2600XT 512 MB DDR3 PCI-e DVI TV out 149,00
• Radeon HD 2600XT 256 MB DDR3 PCI-e DVI TVout - 99,00
• Radeon HD 2600PRO 512 MB DDR2 PCI-e DVI TVout 89,00
• Radeon HD 2600PRO 256 MB DDR2 PCI-e DVI TVout 69,00

Radeon HD 2400 series:

• Radeon HD 2400XT 256MB DDR3 PCI-e DVI TVout 59,95
• Radeon HD 2400PRO 512MB DDR2 PCI-e DVI TVout 54,95
• Radeon HD 2400PRO 256MB DDR2 PCI-e DVI TVout 44,95

And that makes the prices even more interesting and with all the memory configurations even more diverse. Highlighted bold is the Radeon HD 2600XT 256 MB DDR3 is the product most of you will buy. And at 99 EUR that might not at all be a bad deal eh ?

The Radeon 2600 has native Crossfire; so does the 2400 XT.

Crossfire means that you can hook up two graphics cards in your system, connect them and double up your 3D rendering power.

Most of you know this, but the previous generation products, except the X1950 Pro and the low-end segment, had to use an Y-Cable to be able to run Crossfire. Ever since the Catalyst 6.5 drivers you'll be able to hook up similar Radeon X1000 series graphics cards from the low and mid-range segment, up to the X1600 without the need for a master card AND you do not need the Y-Cable. Just plug these cards preferably into a (2x) x16 PCI-Express lane Crossfire compatible mainboard and it should work.

Last-gen crossfireThe high-end series required that Y-cable (great name because often I asked "Why"...  Why is that cable needed ?) Well, ATI used it to composite images between the two cards. ATI is producing a digital image from the DVI output of the slave card and then sends it to the large connector (DMS-59) on the master board. The master board will, on its terms, prepare its image and then sends off both to a compositing engine that is processed on the master board. The master card is responsible for "fusion" of the images between the two boards and that can be done in a number of varieties. So that is why you needed a primary card, you have two cards rendering images and then there's is a compositing engine need which is located on the master card.

Software wise this is pretty much all you need to do to in Catalyst software is opt; Enable Crossfire.

The new situation
ATI basically natively incorporated the compositing engine that was located on the CrossFire Master card right into the GPU die. This is now effective with all Series 2600 and 2900 products.  So there's no need anymore for a master/slave card. To run the cards in a CrossFire configuration, all you have to do is connect them via a pair of ribbon cables, very similar to NVIDIA's SLI bridge. These cables for the time being will actually be bundled with the video cards and not the motherboards, because there are a plethora of Intel 975 and P965 boards already available that are CrossFire compatible that don't ship with the appropriate connector cables.

So ATI/AMD will be including that CrossFire connector with each card moving forward from now on. Some advantages over the old situation:

• plug and play setup
• no master cards needed anymore
• integrated compositing engine
• dual-link DVI inter connect
• resolutions up-to 2560x2048 supported

On the example photo below you can see the new CrossFire connectors:

Here's where we start a copy-paste from our Radeon HD 2000 reference review, DX10, Tessellation and architecture.