Introduction

Back when we first got our hands on the HD6970 from AMD we found it to be a good performing card, but intolerably noisy and hot. To be one or the other is not good, but acceptable. To be both isn't so fancy.

Of course there are two major ways to be cool and quiet. Either have a third-party cooler with a much better design and array of fans or, as is the case here, put the whole thing into a watercooled loop.

Watercooling has moved a long way from the early days and with non-conductive liquids and much higher quality fittings it's no longer the scary upgrade it once was. The major problem is the voiding of your warranty should you choose to fit a waterblock to your graphics card.

PowerColor have helpfully got around those problems by fitting a full-cover EK water-block to their HD6970 to give us the LCS HD6970 and that's what we're taking a look at today.

Technical Specifications

Beneath that Acetal top beats a standard HD6970 overclocked just shy of the 940MHz that we find on the PowerColor PCS+. If there is one thing that the watercooling should ensure it's much greater overclocking headroom than we saw on the PCS+.

Time to get up close and personal with the LCS.

Up Close

Stripped of its plastic shroud the HD6970 looks much better in our opinion. There certainly are enough screws keeping the waterblock tight to the PCB.

As you can see there is plenty of room "left over" as the waterblock is only a single-slot deep but with the twin DVI connections it's still a two slot card.

The looks and quality of the waterblock are both fantastic. Outputs are handled by the standard combination of DVI, DisplayPort and HDMI.

The LCS is provided with fittings for both 1/2 and 3/8 tubing. For our testing we're using 1/2" hose. But I'm getting ahead of myself.

Test Setup

There is a little extra needed to install a watercooled GPU into your system, but whether you have a pre-existing loop or this is your first time dipping your toes in, it's still a simple procedure. For testing we used an XSPC Radiator and, for simplicity, their Drive-Bay mounted pump and reservoir combo. We did not use a CPU block in testing so that the GPU temperatures were able to be accurately read as a best case scenario.

All the watercooling parts used in this review are available from our friends over at www.specialtech.co.uk

PowerColor LCS HD6970
XSPC RS360 Radiator
XSPC 750 Drive-Bay Reservoir and Pump
1/2" Barbs and Hose
Catalyst 11.3 Drivers
Intel Core-i7 950 @ 4GHz
ASUS Rampage III Extreme
Muskin Joule 1200w
6GB Mushkin Redline
Noctua NH-D14
Windows 7 Ultimate x64

Overclocking and Temperatures

Overclocking the PowerColor LCS HD6970 is a joy. Because of the waterblock and our big radiator we know that neither heat nor noise should be the limiting factor.

So it proved.

Loading up Afterburner we could max the slider to 1000MHz on the core without trouble. A .025v bump also enabled us to push the memory up to 4500 MHz effective.

With a little bit of behind the scenes hacking we got the core all the way up to 1096 MHz whilst still 100% stable in all testing. However this was the point at which the old silicon lottery won and the scores were actually starting to drop. So we backed it down to 1050 MHz which is the speed we'll test at.

The temperatures were mind-blowing. After spending the day with Unigine endlessly looping with the settings at maximum the the LCS reached was only 48°C! Cool, quiet and faster than a greased greyhound, this truly is outstanding stuff.

Time for some benchmarks.

3D Mark 11

With the freedom for overclocking that the watercooled LCS brings the performance is excellent. It's a fair whack ahead of a standard overclocked HD6970 and indeed is the best scoring card in our graph.

3D Mark Vantage

Vantage always prefers nVidia cards and their PhysX so while the LCS doesn't top our graph it's still the best of the rest, beating its air-cooled brother pretty handily.

Unigine

The Heaven Benchmark absolutely loves the HD6xx0 cards from AMD and the LCS is no exception. With our phenomenal overclock it once again takes pride of place as the best performing card amongst those on test.

With zero anti-aliasing..

And 8xAA :

Alien vs Predator

Such is the shader performance of the HD6970 and the overclock available from the PowerColor LCS that in Alien vs Predator the LCS HD6970 is up there with the GTX570 Overclocked. Mighty performance indeed.

Crysis Warhead

As Crysis 2 has turned out to be a hideous console port that is only just starting to be patched up to PC Spec, we're stuck with Warhead for much longer than we'd like. However the LCS HD6970 really rocks hard here. That monster GPU Core overclock taking it to new heights.

Far Cry 2

The games change, but the story remains the same. The LCS HD6970 is the HD6970 performance king.

Metro 2033

Even the ever harsh Metro 2033 bows under the weight of performance available from the PowerColor LCS. Not only does the LCS beat the air-cooled HD6970 but it's up there with the outstanding GTX570.

Conclusion

It's no secret that when we reviewed the HD6970 we were disappointed. After the lofty heights of the HD5870, the HD6970 was too loud, too hot and kinda ho-hum performance.

Improved versions fixed the performance issues, but the heat and noise were still intolerable.

Now thanks to PowerColor we have a card that in one fell swoop has decimated the competition and placed itself atop the AMD single-GPU charts.

Out of the box it's fast enough, but with water keeping everything chilled, even in this glorious weather we're experiencing, the overclocking limit ended up being the chip itself rather than a thermal issue. Even then we got right up to a hair shy of 1100 MHz and the performance just kept on coming. It's easily the fastest HD6970 we've tested.

Speed, impressive though it is, isn't the star of the show. No Sir. The most impressive factor is how well the full-cover block works at keeping everything frosty. A whole days running of Unigine at maximum settings couldn't push the temperature past 48°C which, we're sure you'll agree, isn't warm at all. Hell we've seen cards that idle at around that.

Noise is equally suppressed because you're not attempting to keep a tiny bit of copper cool with a single fan. Instead, with the enormous surface area available in radiators and thermal benefits of liquid cooling, you just need a breeze across your radiator so can use quiet 120mm fans.

Obviously there is a price to pay for a factory fitted waterblock, but whereas most companies know that only the enthusiasts will have a water-loop and price their products at a level where you feel they need a pistol and a mask, the PowerColor LCS HD6970 is only £20 more than the price of buying a card and block and doing it yourself would be, at £360. Not only is the hassle of fitting the waterblock taken out of your hands but because it's factory fitted you still get the excellent PowerColor warranty to give you piece of mind. Maximum kudos to PowerColor for not taking the Highwayman approach to the pricing on the LCS.

It's a stunning product and one we happily give our OC3D Gold Award to.

Thanks to PowerColor for providing the LCS HD6970 for review. Discuss in our forums.