ATI 69xx Series launches - Crocodile Dundee beware

Wednesday 15th December 2010, 12:26:00 PM, written by Rys

Today, on a rather enjoyable December the 15th, ATI decided it could not procrastinate any more and launched the 69xx family of cards, codenamed Cayman (B3D codename to be disclosed at a later date). And geek senses tingled everywhere, because it marks the most significant departure from the R6xx lineage we can remember (one could argue the RV7xx was that, but we digress).

Since Rys is in rehab over the disappointment, I'll drop the news: the RysUnit is gone! So, VLIW width moves from the perennial 5 to 4, giving room for some amusing claims like "DP throughput improved, now quarter rate", "higher utilisation"...well yeah guys, keeping the numerator the same and reducing the denominator tends to have that effect, you know? The texturing and cache hierarchy seem to be a direct port from Cypress, with some probable tweaks here and there.

Annoyed at the constant trolling over crucial gaming titles like Unigine: Heaven or Stone Giant, ATI's architects decided it was time to move to fully parallelise the triangle setup stage, so Cayman is capable of ideally spitting out two fully setup triangles per cycle. Early data shows this to be a rather consistent improvement.

Finally (well, not quite, but this is just a newspiece!), we get PowerTune, or in other, simplified words, dynamic clock adjustment to maintain TDP. Dynamic clocking based on TDP limits is not that new for CPUs, Intel having dabbled with in many instances, for example the ill-fated Foxton, or the rather succesful Turbo, but as far as we know this capability is an absolute novelty for GPUs. The main difference is that ATI marketing decided to go for a top-down approach (here's the maximum clock, we may take it down to maintain the set TDP), versus what the CPU guys are doing (here's the minimum non-powersaving clock, we may take it up if we're under the set TDP). That's a significant simplification, and you'll have to wait until our article for a more in-depth look, but for what it's worth we think PowerTune falls into the "good idea" category.

Speaking of the actual hardware, the chip is claimed to pack 2.64B transistors in 389 squared mm, which translates into a density hit slight density win versus Cypress, and still nicely petite compared to the competition. The SKUs you'll be able to buy from the store are the 6970 and the 6950, with the 6970 clocking in at 880MHz E/1375 (5500)M. It packs 1536 ALUs, 96 TUs, 32 ROPs and an ample 2 GB of GDDR5 on a single, long-ish PCB. The 6950 drops down to 1408 ALUs, 88 TUs, with clocks at 800MHz E/1250 (5000)M, all else being equal. We're not sure about pricing, so you'll have to figure that one out.

The really good news is that, in an unexpected twist, we should be getting a Cayman based GPU sooner rather than later, and by way of consequence we should have an architectural investigation out in actually reasonable time (fingers crossed). Until that happens though, we can wholeheartedly recommend our friend Damien's work, as well as the ever excellent Tech Report coverage for a first date with the hardware.

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