AMD (ATi) HD 5970 The New Undisputed Champion

Did you ever think ATi would ever wrest that title from nVidia? I certainly did not, simply because I tend to believe in the superiority of nVidia. Oh, sure, ATi has had good designs, but as I have stated here before, ATi for many years could not produce a competent driver to save their collective soul.

Now we are having an almost complete change of scenery. nVidia can’t deliver the top performer right now, and ATi is delivering (at least) acceptable drivers for their hardware.

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PC is calling the new Radeon HD 5970 Dual GPU card the Undisputed Champion and gives the exegesis below -

You can forgive AMD for stealing a line from Nvidia’s playbook. From the name and marketing materials, it’s not obvious that this card is a dual GPU card. One AMD chart even refers to the card as the “ATI Radeon HD 5970 GPU,” much like Nvidia’s 295 GTX is a dual GPU card that’s sold as if it were a normal graphics card.

Most features simply double, since there are two identical GPUs with the same memory per GPU. However, note the memory bandwidth is lower, since the memory clock is lower. Also, overall compute performance isn’t quite double, since the engine clock for each GPU defaults to 725MHz, rather than the single GPU 5870’s 850MHz.

In addition to the paired GPUs, the card maximizes performance with a new second generation PLX PCI Express 2.1 bridge chip. This speeds up communications between the two GPUs

As someone who started using computers when they used 8088 chips, the fact that a graphics card could hold this much performance is astounding, and the need for just shy of 300W for its proper powering is almost beyond belief.

The older Radeon HD 4870 X2, AMD’s last dual GPU card, often suffered from serious overheating problems, so ATi has taken steps to improve overall thermal efficiency. The first step is to used specially screened GPU chips with the minimum amount of leakage current. The thermal system consists of a vapor chamber, with heat dissipation via a fully vented exhaust system. Finally, a multipoint, programmable PWM fan controller ensures fan speeds consistent with overall thermal output. The whole affair is rated to dissipate 400W, or over 100W of headroom.

This is truly excellent, because so many people I know have had problems with overheating, though the build was so carefully planned from the start. I have seen many $400 purchases become $700 ones because there was no way to use the graphics card successfully without the use of liquid cooling. Then there is always the fear of problems with those setups. The extra cooling headroom means that with a roomy case, and a few 120mm fans, it might be possible to keep within the thermal envelope of the card, and thereby staying within the limits for the entire system. (Many times the heat from a power hungry video card shoves the entire system [CPU, hard drives, RAM] off the thermal cliff.)

The use of low leakage GPUs suggests that the core clock speeds could be pushed higher than the default 725MHz. Given that the card can dissipate 400W of overall thermal output, ATI has decided to leave the card unlocked, letting users overclock it to their heart’s content. The company is even making available an overvoltage tool, and suggests that the card has enough headroom to push the engine clock to above the 850MHz of the single GPU HD 5870 and the memory speeds up to the 1200MHz of the 5870. In The HD 5970 also sports sophisticated digital voltage regulators, real time power monitoring and Japanese pure ceramic capacitors, which facilitate higher clock speeds. (The reason for the more conservative default clock speeds is that the company needs to make allowances for the thermal environment inside PC cases, which may be less optimal.)

What about power efficiency? The HD 5970 offers the same clock gating capability as the single GPU variant. In addition, the card offers an ultra low power state that puts one GPU to sleep, which cuts the overall power draw of that GPU by half the normal idle performance. The card idles at 42W, only 15W higher than the 27W of the HD 5870. Of course, the card sucks 294W at full throttle – and that’s at the default clock speeds. So you’ll need a power supply with the later PCI Express 8-pin power connector – the HD 5970 uses one eight pin and one six pin connector from the PSU.

I have yet to see a mention of the ability to power any of these cards down from that idle draw, though the Hybrid CrossfireX capability of Windows Vista and Windows 7. Dropping it lower than 42W would be very nice.

The HD 5890 seems much better behaved than its predecessor, the HD 4870 X2. Although the HD 5970 fan noise became quite audible at high loads, it seemed much quieter than the 4870 X2. More telling was our experience removing the cards immediately after completed benchmarking runs. The 4870 X2 was extremely hot to the touch – we had to handle it carefully to avoid burnt fingers – while the 5970 was cooler to handle (though still very warm.) Much of this was no doubt due to the vapor chamber covering the back side of the card.

It would seem that this card is going to stay within the rated power, which unlike several predecessors would make planning for proper heat dissipation much easier than before.

My driver research team (my son and a couple of his game playing friends) states that nVidia has been slipping lately, and that their drivers are not as solid as they should be, and ATi has come up in the world, with better solidity to theirs. (What a turn of events that is!)

The article continues after showing some graphics detailing specifications and performance with -

There’s no question the Radeon HD 5970 is the fastest single desktop graphics card you can buy today. The real question is if it’s worth $200 more than a single Radeon HD 5870. Certainly if you’re running a 1920×1200 display, we’d recommend the single GPU card. But if you’re running triple displays, or a 30-inch, 2560×1600 monitor, and you want to push polygons at full resolution, you should consider the Radeon HD 5970. But make sure you’re willing to pay the cost.

Not many are, or these cards would be much cheaper than they currently are. But with Eyefiniti, the chances of these cards becoming much more popular is there, so we can hope for that price decrease.

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Technorati Tags: AMD. ATi,HD 5970,DDR5 memory,speed,lowered heat,better cooling solutions,bests nVidia GTX 295,Eyefiniti,multiple display capability,Display Port

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Day: A period of twenty-four hours, mostly misspent.

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