Product: AMD Radeon HD 6990
Company: AMD
Authour: James Prior
Editor: Charles Oliver
Date: March 15th, 2011
Design Characteristics & Warranty

VISION Black
VISION Black
The cancellation of TSMC's 32mn manufacturing process in 2009 has some knock on effects for the HD 6000 series. Besides the Ibiza design becoming Cayman, Antilles is a rethink of what AMD can do with their technology. The ATI Radeon HD 5970 was a sub 300W part (just), by dint of clock speeds and voltages - it used the full 1600 STREAM core part from the HD 5870 but ran HD 5850 clock speeds, using cherry picked ASICs for lowest leakage; lowest power. Additionally, the traditionally conservative overclocking limits in CCC were raised, for the HD 5970 to be all it could be when you ramp up the core and memory clock voltages using the included voltage tool for overclocking.


With the HD 6970 already running 250W max board power, with an average max gaming load of 190W, sticking to 300W TDP for the dual-GPU 6000 series part was unfeasible. Sure, two Cayman Pro specification ASICs with cherry picked cores, lean memory and tighter PowerTune limits could have delivered a product, but would it be worth it? AMD apparently decided no - we're not wasting our tasty high-yield awesome Cayman XTs as gimped Pros in our flagship; AMD equipped the AMD Radeon HD 6990 with clocks to max out the 375W power budget offered by dual 8-pin power inputs. Next they cranked it up to 11, by including the full Cayman XT engine clocks and a core GPU voltage bump, using the dual BIOS feature. Both settings feature higher CCC Overdrive limits, for more overclocking action.

Our Antilles Came In A Silver Briefcase
Our Antilles Came In A Silver Briefcase

AMD's cooling solution again uses vapor chamber technology, with a phase change thermal paste. This paste is good for one application only, and hardens after heating. Once you pull the heatsink you'll have to replace the thermal paste - standard operating practice for seasoned computer builders - but you might get higher temperatures, as AMD estimate 8C of the cooling capacity is from the use of this advanced thermal paste. There's no easy way to get to the fins on the vapor chambers, so regularly cleaning with a compressed air can to keep them free of fornicating dust bunnies is probably a good idea.


The rear of the HD 6990 is cleaner than the HD 5970 product it replaces in AMD's stack, with a full slot exhaust and a single line of display outputs. A single Dual-Link DVI output is provided, with four mini-DP outputs. Included with the card are a set of mini-DP adapters, offering another DVI output, a HDMI 1.4a output, and an active Single-Link DVI adapter. These adapters provide for 3-display DVI Eyefinity, and 5-display Eyefinity out of the box. AMD estimates these adapters to be worth $60 - a nice added value for those planning on multi-panel gaming.

Symmetric Board Design
Symmetric Board Design

The Warranty Debate

The AMD Radeon HD 6990's warranty has been the subject of some debate. The problem is with who gets warranty support and by whom. End users, consumers, have rights that vary from locale to locale. Almost universally, you can't sell a product with a shipping configuration you don't offer warranty. Consumers, for the most part, get support for a limited amount of time from the store they purchase from, and then from the manufacturer. AMD has not manufactured their own graphics cards in several years - all cards are made by partners. This is a little disingenuous though, as AMD controls who buys how many GPUs, and what boards and specifications they can use, but ultimately the manufacturer is the Add-In Board (AIB) partner and not AMD, who remains a fabless design company.

So, do you get warranty on your HD 6990 in both BIOS modes? Yes, you do, but you'll have to deal with the AIB support department for them to approve your RMA should you have problems - just as you do now. Likely they are going to want to know about your PSU and case cooling, to ensure you have the basic minimum requirements. Depending on how diligent the RMA department want to be, they may ask you about overclocking, too. AMD, and AIBs, do not guarantee parts that are overclocked, be it via their software or other means. The problem is, that's the point of this product: the overclocking potential.

Dual 8-pin Power Connectors with PowerTune = 450W?
Dual 8-pin Power Connectors with PowerTune = 450W?

The ATI Radeon HD 5970 came similarly specified. Shipped without PowerTune technology, AMD loaded it with 725MHz core clocks and 1000MHz memory clocks, and lowered voltages for both to stay within 300W TDP and board power. An included software tool allowed the end user to bump up voltages for higher overclocking - something AMD facilitated with much higher Overdrive limits in CCC. Users of the ATI Radeon HD 5970 were warned that if you damaged the card by overclocking it, you were not covered by any warranty. This was despite the fact the Cypress XT cores on the HD 5970 were cherry picked full 1600 STREAM core chips, fully capable of running 850MHz at full voltage. Likewise the RAM chips had no issues with running 1200MHz, their rated speed, once the voltage was increased. The difference was the AIB couldn't tell if you'd done that or if you'd bumped GPU core voltage to 1.25v and tried to run the GPUs at 1GHz. They just got a dead $600+ card back to replace. Times change, and with the HD 6990's BIOS switch sticker, it is now obvious if the OC mode was used and more voltage applied.

For the consumer, if all you did was move the BIOS switch, you should be covered by warranty (depending on terms of your local laws, that may turn into a 'must be covered'). You might have to argue with the AIB's RMA department to get them to perform the RMA, should you need one. Which, if you run stock configuration (either BIOS), with a suitable PSU and cooling solution, shouldn't be needed in our opinion. The problems lies with how much effort the AIBs will make to ensure only genuinely defective cards are returned to them, and not ones where the PEBKAC killed it. This is likely to be 'a lot of effort', as AMD is not supporting the AIBs on cards that have been returned with the BIOS switch moved. Considering these cards feature screened ASICs selected for their tested operation, there should be few reasons to worry about a bad card at stock speeds with appropriate power and cooling. The PLX bridge chip connecting the two ASICs is the same from the HD 5970, the memory chips are also used in the HD 6950 and 6800 series, leaving the Volterra digital high power VRMs as the main new part.

Given the trouble AMD went to, with a dual-BIOS, 450W cooling solution, raised PowerTune limit and Overdrive core clock limits, it seems somewhat ridiculous to consider that this configuration is not covered by warranty from AMD to AIB. The AIB that slapped their sticker on it will likely have to provide warranty support the card to the consumer, even if you use the OC BIOS. Then the AIB has to wrangle with AMD and the component vendors about who is eating the cost of the defect. As a consumer, you still get warranty support, but the manufacturer you pick is going to be critical to how pleasant your RMA experience is going to be, should you have issues.


If you think about who might buy this card, it generally comes down to two types - the boutique buyer, looking for as little hassle for the most performance as possible; and the balls out performance enthusiast. The boutique user is less likely to overclock - they don't care to mess with two cards, multi-GPU bridges, configuring drivers, lots of cables plugging into cards inside: they just want a simple plug'n'go powerhouse solution and they're willing to pay for the convenience. These guys won't be affected by the warranty foibles as they won't peel off the BIOS sticker.

It's the second kind, the ultra performance enthusiast, attracted by the compact form factor and higher overclocking limits that will most likely be affected by the warranty shenanigans. Some of them won't care, as they're just going to slap whatever watercooling or triple slot replacement heatsink and fan cooling kit they can make work on their card and be happy. The remaining souls, the majority of people who buy the HD 6990, are going to be pissed that they can't even try out the BIOS OC mode without worrying about wrangling with RMA support monkeys and possibly flushing $700+ down the toilet. $700 ought to buy excellent performance and support, not worries.

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