Rumour control – ATI Radeon HD 4850 and 4870 specs leaked

Posted at: 3:15am 23rd April 2008 by Ben Hardwidge

Specs of Radeon HD 4000-series GPUs are apparently leaked by German tech site, showing the GPUs' shaders clocked higher than the core clocks

It’s been a long time since ATI / AMD launched a brand new GPU architecture. The Radeon HD 3000 cards were better than the 2900-series cards in terms of bangs per buck and power consumption, but they didn’t add anything new in terms of the number of stream processors and basic architecture. This could soon change, though, if the latest rumours about the Radeon HD 4000 GPUs are to be believed.

The German tech site Hardware-Infos has apparently got hold of the specs for the Radeon HD 4870 (codenamed RV770XT), 4850 (codenamed RV770Pro) and 4850 GDDR3, and has published them online. If the specs are to be believed, then the new 55nm chips will feature 480 stream processors, rather than the 320 found in the 3850 and 3870.

One of the most interesting claims on the site is that the GPUs’ stream processors will apparently be clocked at a higher frequency than the core clock, much like Nvidia’s DirectX 10 GPUs. Hardware-Infos claims that the 4870 will be clocked at 850MHz, with a stream processor clock of 1,050MHz and a GDDR5 memory clock of 1,935MHz. Meanwhile, the 4850 will have a core clock of 650MHz, a stream processor clock of 850MHz and a GDDR5 memory clock of 1,728MHz. At the bottom of the pile, a GDDR3 version of the 4850 is also claimed to be in the works, with a memory clock of 571.5MHz (1,143MHz effective).

If the table is to be believed then the 4870 will come with 1GB of memory as standard, while the 4850 will come in 512MB GDDR5 and GDDR3 versions, with a further 256MB GDDR3 flavour at the cheaper end of the scale. Interestingly, Hardware-Infos says that all three GPUs will feature a 256-bit memory interface, just like the interface found in Nvidia’s new GeFOrce 9-series GPUs. All the GPUs will also have 16 ROPs and 32 texture units, according to the site.

Hardware-Infos claims that a 4870 card will have a TDP of 150W, while 4850 cards will have a TDP of 110W. If the table is correct, then the GPUs are scheduled to be announced next month.

Of course, as with any Web rumours, this could all be a load of fluff to rack up a few hits, but the specifications look pretty plausible to us. The only bit that sticks out is the GDDR5 memory, just because we haven’t seen a GDDR5 graphics card yet. However, ATI also surprised us by being the first company to introduce us to GDDR4 memory with the Radeon X1950XTX back in 2006, and it may have similar plans for GDDR5.

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