AMD's HD6990 might be a frame rate-crunching monster of a card, but its dual cores are kept cool by the same old wee AMD Red reference design fan. That may be fine for a single card, but is really pushed trying to keep two serious graphics cores cool – especially when the card is being ridden hard by the polygon cowboys.

Although it may sound like a vacuum cleaner, that reference fan's cooling capabilities don't match up to the decibels. And you can stop sniggering at the back too, Nvidia's reference cooling fans are just as bad. Even though it's right at the top of the food chain, and out of a great many people's financial reach, the HD6990 has desperately been in need of some love from third party cooling ever since it was released.

Enter the Arctic Cooling with its Accelero Twin Turbo 6990 cooler. As you might have guessed from the name, it uses two 120mm fans and a 10 heat pipe design heatsink to keep the AMD beast cooler and quieter than the reference design.

Banshee to whisper

When you first see the size of the Twin Turbo 6990 and its dual 120mm fans (adding another 820g to the weight of the PCB) you might have an inkling about what it can do, but nothing can quite prepare you for the difference it makes.

When the 6990 is under 100 per cent load it goes from a screaming banshee you can hear across the other side of the room to something that's barely audible, even when you're standing next to it. It really takes some listening to believe it.

To test the cooler, we ran the card at the stock 830MHz core speed and the overclocked 880MHz core speed available via the card's BIOS switch to really push it under load. As you can see from the test results, the fans occasionally peaked at 1,102rpm under full load but were generally running in the region of 828-834rpm.

In a stroke, that accounts for how quiet the cooler is in general gaming use. The fans not only quieten everything down, they also help transform the thermal dynamics of the card.

With the standard cooling the card gets to a very toasty 88ºC at 880MHz under full load and the single reference fan struggles to cope – hence the noise. The Accelero Twin Turbo drops this by some 16ºC though, which is quite some feat.

TechRadar Labs

100% load cooling performance
Core temp: Degrees centigrade: Lower is better
Accelero Twin Turbo (830MHZ): 68
Reference cooler (830MHZ): 81
Accelero Twin Turbo (880MHZ): 72
Reference cooler (880MHZ): 88

100% load fan performance
Fan speed: RPM: Lower is better
Accelero Twin Turbo (830MHZ): 1,092
Reference cooler (830MHZ): 2,870
Accelero Twin Turbo (880MHZ): 1,102
Reference cooler (880MHZ): 3,103

The result is that you still get a frame-crunching monster, but one that's now so quiet in operation that pushing the card to its maximum no longer needs the addition of ear plugs.

When it comes to ripping apart £500 plus graphics card to replace the cooler, you want the replacement cooler to come with a decent set of instructions to help calm your nerves if nothing else, and here Arctic Cooling has excelled. The instruction sheet supplied with the Accelero Twin Turbo is superb. At first glance it may look too simple, but everything you need to know is clearly explained with the aid of illustrations – both for the dismantling of the original cooler and the fitting of the new one.

Yes, it might be expensive, but this is also amazingly good at what it does, changing a screaming banshee of a graphics card at full load into something barely audible.

Overview

It may look like a jet turbine on top of your CPU, but can the Deepcool Fiend Shark live up to its platform cooling claims?

Right then first things first, we must be honest, we don't get the name either. But someone at Deepcool obviously has an attraction to sea life as there is a Tiger Shark and a couple of Killer Whale's in their product line-up too.

You just know by the sheer size of the box it comes in that the Fiend Shark is a bit special, but even so, its size may still surprise you, as will the care taken with the way the contents are packed.

It certainly puts most other cooler manufacturer's to shame in that respect, with its fixing components all having their own separate space in the two plastic packing trays.

It's a beast of a thing and certainly the biggest top-cooler we have seen for quite a while, and it certainly looks the part with its bright blue 140mm cooling fan and nickel plated heat-pipes and cooling fin array.

Unfortunately though, when it comes to its performance, it doesn't quite live up to that billing.

Benchmarks

To test the coolers we used an Asus P8Z68-V motherboard and an Intel i7 2600K which we overclocked to 4.6GHz for overclocked part of the testing.

To stress the CPU we ran the Small FFT's test of Prime95 for 20 minutes using the RealTemp utility to measure the core temperature's, averaging out the temperature for all the cores.

Standard clock performance

Overclocking performance

Peak to idle performance

Verdict

Despite the enormity of the cooler, the Fiend Shark is surprisingly easy to install and the clear instructions help with this.

Unusually instead of the usual tiny screws to fix the mounting brackets to the heatsink there are just two hefty thumbscrews, one each side to do the job.

It can though prove a little tricky to get started if you aren't blessed with thin fingers...

In the marketing spiel for the Fiend Shark you might notice it claims to be able to cool the surrounding motherboard components down. But don't be overly sucked in by all this, as all top flow chillers cool surrounding areas to a certain extent.

Because of its sheer height of the device (131mm), and its 140mm cooling fan, it is a little more effective and noticeable than most. Or to put it another way, if you put your hand under the cooling fin array you can certainly feel the draught, but only when the fan is being seriously pushed.

Under normal conditions the slightly tweaked UBF140 fan is pretty dammed quiet, with a quoted noise level of just 18.2dBA 700rpm, which rises to a much more audible 32dBA at 1400rpm when it is shifting an impressive 80cm3 of airflow.

When it comes to performance though the Fiend Shark, despite its size and comparatively huge 140mm fan, is a bit disappointing.

This is especially true when it's compared to the tower coolers we've recently reviewed. But then most top fan coolers do seem to lack a little when compared to their tower brethren.

Adding to the problem with the Fiend Shark is the price tag, which makes you feel that it really should be performing better than it does.

We liked:

The Fiend Shark certainly looks the part and its installation should be a lesson to all those cooler manufacturers who seem to revel in making fitting a CPU cooler to a motherboard as complicated and as tortuous as possible.

It's also tall enough to allow the fitting of some fairly hefty heatsink equipped memory modules into the DIMM slots.

We Disliked:

It has to be said that given its size we were hoping for more from the Fiend Shark, yes it's quiet at stock speeds but then if you want a quiet cooler there are plenty around for a lot less money.

Given its size it looks like a cooler aimed at overclockers, but given our test results if you are looking for air cooling for some pretty extreme overclocking your probably better off looking elsewhere.

Final word:

Looks impressive but unfortunately suffers, like most top-coolers do, in comparison with their tower cooling competitor's.

This might be Enermax's first venture into the world of the CPU cooler, but from the build quality and performance of the ETS-T40- TA you would never guess that. It outperforms every other cooler in this round up, and as you might expect from a company that's been cooling PSUs for years there's also some interesting design work.

The ETS-T40-TA has a fin design that helps improve air flow especially around the dead zone behind the heatpipes.

Installing the ETS-T40-TA is straightforward although like most of the coolers, it requires that you fit a motherboard backplate. Enermax has clearly spent time on the mounting – even down to providing a spanner – and it's one of the quickest to fit.

The 120mm cooling fan used with the Enermax is quiet but only in terms of its spin performance; the appearance it gives is one of real bling. Usually when you talk about LED fans you'll find an LED in each corner, not so with this one, it had a row of them around the frame.

Just in case that hasn't quite got your attention the fan blade edges have a chrome strip applied to them. Its a credit to Enermax that it also offers a version of the cooler without all the bling.

It should come as no real surprise that a company that has been producing some excellent PSU designs for over two decades should produce a winning CPU cooler design first time out of the box.

Apart from screwing on either the AMD or Intel fixing plates to the heatsink contact base, the rest of the mounting kit for the Gelid GX-7 comprises fitting four bolts which run through the motherboard base plate. Securing them in position with nuts works okay, but we ran into a slight snag with our Asus motherboard in so far as the board layout.

There are two passive heatsinks cooling the power components by one of the cooler mounting holes, which makes it slightly tricky for anybody with sausage fingers to get the locking nut tight.

In any case the cooler itself is fixed to the bolts with a second set of threaded locking pins which have springs to prevent over tightening. Keeping everything cool is one of Gelid's own, very efficient 120mm wing fans, which spins from 600rpm up to 1,800rpm with a rated noise level of between 10 and 26.8dBA.

The cooler can, in fact, take two fans, Gelid supplying the wire mounts for a second fan in the box bundle. Gelid has also extended the edges of the cooling fin array to make a clever fan holder.

TechRadar Labs

CPU standard clock (2600K @3.4GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 24
Cooler Master GeminII M4: 25
Cooler Master Hyper TX3 EVO: 22
Gelid GX-7: 22
Enermax ETS-T40-TA: 21

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 52
Cooler Master GeminII M4: 61
Cooler Master Hyper TX3 EVO: 63
Gelid GX-7: 55
Enermax ETS-T40-TA: 50

CPU Overclocked (2600K @ 4.6GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 25
Cooler Master GeminII M4: 26
Cooler Master Hyper TX3 EVO: 24
Gelid GX-7: 22
Enermax ETS-T40-TA: 22

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 72
Cooler Master GeminII M4: 83
Cooler Master Hyper TX3 EVO: 85
Gelid GX-7: 78
Enermax ETS-T40-TA: 70

Performance-wise the GX-7 sits comfortably in the middle of the pack for all the tests, which marks it out as a bit of an all-rounder. It's good to see Gelid try something different to make a mark in a crowded market space, in this case it's the neat and tidy way it's incorporated seven heatpipes into the design.

Apart from the new fan, the other major change with the Cooler Master Hyper TX3 Evo is that this latest version doesn't support the oldest AMD Sockets; 754, 939 and 940 have dropped off the list.

It will support every AMD socket up from them with all Intel sockets from the 775 up to, and including LGA 1155 are also supported.

The cooler comes with a 92mm fan attached but should you require more cooling then Cooler Master includes mounts in the box for a second 92mm fan. The fan mounts are made of plastic and look rather like the fan mounts you find in some PC cases. This makes a nice change from the usual sprung wire mounts, often a source of irritation when it comes to sticking the fan on the cooler.

Performance-wise the Evo keeps up the family tradition by offering very good result at a very keen price point. Although it's not quite as efficient as some of its more expensive rivals when it comes to keeping the CPU cool when worked hard or overclocked.

TechRadar Labs

CPU standard clock (2600K @3.4GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 24
Cooler Master GeminII M4: 25
Cooler Master Hyper TX3 EVO: 22
Gelid GX-7: 22
Enermax ETS-T40-TA: 21

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 52
Cooler Master GeminII M4: 61
Cooler Master Hyper TX3 EVO: 63
Gelid GX-7: 55
Enermax ETS-T40-TA: 50

CPU Overclocked (2600K @ 4.6GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 25
Cooler Master GeminII M4: 26
Cooler Master Hyper TX3 EVO: 24
Gelid GX-7: 22
Enermax ETS-T40-TA: 22

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 72
Cooler Master GeminII M4: 83
Cooler Master Hyper TX3 EVO: 85
Gelid GX-7: 78
Enermax ETS-T40-TA: 70

To be fair though it's not aimed at overclockers and performs better than its price tag suggests. The TX3 Evo certainly gets a major thumbs up when it comes to how easy it is to fit, mainly due to the fact that once you've attached the Intel push pin assembly then it's a direct swap-out for the standard Intel cooler.

It's also very quiet, a far bit quieter in fact than its predecessor thanks to the new sleeve bearing fan it uses.

The Cooler Master GeminII M4 uses the direct contact method of shifting heat awat from the CPU. Instead of the heatpipes passing through the contact base, in this method they are flattened and become an integral part of the bottom of the contact plate, directly touching the heat shield on the top of the CPU.

To get to its amazingly low height profile (just 59mm tall) the cooler uses four standard 6mm U-shaped heatpipes but turns them on their sides to allow for a more compact design. And the newly-designed XtraFlow 120mm fan sitting on the top of the cooler is just a mere 15mm thick.

As you can see from the figures, the GeminII M4 isn't a cooler designed to be used in heavy overclocking situations and to be fair to Cooler Master it doesn't make claims that it is.

A 2600K maxes out at around 98ºC and while the GeminiII M4 has no problems keeping the CPU cool even under load at stock speeds, it's a different story when the core is overclocked and under load. The M4 struggles to hit 85ºC, which is a tad high for continuous use.

TechRadar Labs

CPU standard clock (2600K @3.4GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 24
Cooler Master GeminII M4: 25
Cooler Master Hyper TX3 EVO: 22
Gelid GX-7: 22
Enermax ETS-T40-TA: 21

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 52
Cooler Master GeminII M4: 61
Cooler Master Hyper TX3 EVO: 63
Gelid GX-7: 55
Enermax ETS-T40-TA: 50

CPU Overclocked (2600K @ 4.6GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 25
Cooler Master GeminII M4: 26
Cooler Master Hyper TX3 EVO: 24
Gelid GX-7: 22
Enermax ETS-T40-TA: 22

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 72
Cooler Master GeminII M4: 83
Cooler Master Hyper TX3 EVO: 85
Gelid GX-7: 78
Enermax ETS-T40-TA: 70

The compact design though is a godsend for people who want to put standard, high voltage, processors in the confines of a smaller case. As can be seen from our test results, the GeminII M4 works just fine. It's also pretty quiet in operation too.

As with the Dark Rock PRO C1, the first thing that strikes you about the Advanced C1 is the build quality and finish, which is superb. Even the end of the heatpipes have little black caps on them and the cooling fan includes rubber mounts to cut down any vibration.

Fitting the Advanced C1 is an adventure to find out how many new swear words you can come up with in the time it takes to stick on your motherboard. Admittedly it's not quite as bad as the PRO C1, mainly because it doesn't weigh anywhere near as much, but it's still a pain.

You have to hold on to both the cooler and the motherboard as you try and make sure that the mounting screws stay in the right holes as you manoeuvre the cooler into place.

Although the Advanced C1 weighs in at just over a kilo, it's still quite compact for a cooler equipped with six heatpipes. Each of the 6mm diameter pipes passes through the nickel-plated copper contact plate before passing through the nickelplated cooling fin array.

Performance wise the Advanced C1 is okay, but we just couldn't shake the feeling that with a build quality like the Advanced C1 has, its performance should be a lot better.

TechRadar Labs

CPU standard clock (2600K @3.4GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 24
Cooler Master GeminII M4: 25
Cooler Master Hyper TX3 EVO: 22
Gelid GX-7: 22
Enermax ETS-T40-TA: 21

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 52
Cooler Master GeminII M4: 61
Cooler Master Hyper TX3 EVO: 63
Gelid GX-7: 55
Enermax ETS-T40-TA: 50

CPU Overclocked (2600K @ 4.6GHz)

CPU Idle load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 25
Cooler Master GeminII M4: 26
Cooler Master Hyper TX3 EVO: 24
Gelid GX-7: 22
Enermax ETS-T40-TA: 22

CPU full load performance
Degrees Centigrade: Lower is better

Be Quiet Dark Rock Advanced C1: 72
Cooler Master GeminII M4: 83
Cooler Master Hyper TX3 EVO: 85
Gelid GX-7: 78
Enermax ETS-T40-TA: 70

The one thing that does impress however is just how quiet the cooler is even when the CPU is being overclocked. The rubber-mounted 120mm SilentWings fan certainly lives up to its name, it may not be truly silent but it's dam close.

We got our thermal paste covered fingers on the latest passive GPU cooler from Arctic Cooling, snappily named the Accelero S1 Plus. Designed to plonk right on top of a Radeon HD 6870 (among many other cards), this chip chiller aims to keep your GPU cooler and quieter. But why would you want to upgrade your stock GPU cooler, we hear the uninitiated ask?

Stock GPU coolers are generally just about good enough. If you're just using your graphics card in your normal desktop machine with no thought to overclocking, then you can pretty much just leave it well enough alone if you want.

If, however, you really want to push your GPU to its limits, then replacing the standard cooler with something more heavy-duty is the best way to do it.

There is another reason to change out your GPU cooler though and that's silence. If your whining graphics card is driving you to distraction then you may want to think about changing to a passive version such as the Arctic Cooling Accelero S1 Plus.

The top passive graphics card we've seen is the Asus EAH6770 DC; that's about as powerful a graphics card as you will want to try and cool without messing with spinning blades.

But wait, this here £20 passive replacement cooler is capable of sitting pretty on the current budget GPU of choice, the HD 6870. Bonus.

Sadly, no. While it does happily fit, after a little thermal paste mixology and some fiddly screw-driving, it simply isn't conductive enough to adequately cool such a graphics card on its own. The basic Sapphire cooler on our Radeon HD 6850 kept it to 62°C under load while the Accelero S1 maxed the GPU out at 105°C. It was certainly quiet, but way too hot for continual use.

You can try putting in a 'turbo module' for the Accelero, which is a chunky 90mm fan that will provide more cooling. It should turn out to be quieter than the standard Accelero, but if you're hoping for some fairly high-end, passively-cooled gaming it's not going to be found here.

Whether you're into your overclocking or simply determined to keep internal case temperatures to a minimum, we reckon a self-contained liquid cooling kit like the Antec Kuhler H2O 920 offering is your best bet at the moment if you're prepared to pay a bit extra. Or maybe a lot extra.

The 920 is pricier than some like Antec's own £40 Kuhler 620, and the difference between this kit and entry-level liquid cooling is subtle. But that's often the way with enthusiast gear – some people will always be willing to pay top dollar for that extra one per cent.

That's not to say the difference is that slim between the 620 and 920. There are two 120mm fans to strap to the radiator, one keeping the aluminium corrugation cool before the hot liquid arrives, one on the other side to chuck it out of your case.

These fans hook up to the pump, which hooks up to a spare USB controller on your motherboard. That lets you control the fan speeds via a software layer once you get to Windows.

Ready, set… blow!

It all sounds a bit like last month's Corsair H100, doesn't it? Well, there are some key differences.

Corsair's radiator is twice as long, which makes it compatible with only certain cases, and rather than using a software layer, fan speed's adjusted by either pressing a button on the pump itself, or hooking it up to Corsair Link, which monitors temps all around your case.

The two liquid cooling kits are roughly the same price, though we did manage to find the Corsair H100 for £76 at the time of writing.

It's not quite a straight performance stand-off between the two, though. As the Corsair stands limber and ready to draw its pistols, the Kühler H2O 920 struggles to get its six shooters out of its holsters. And by that opaque metaphor, we obviously mean that Antec's bracket design lets this kit down.

Quite simply, it's a pain in the perineum to fit, especially in light of the H100's effortless bracket design. After the swearing dies down and the H2O 920 is fitted, the results are pretty agreeable. We're especially impressed by its low load temperature with the fans running at 100 per cent, and the swift load to idle recovery time of around 12 seconds.

However, the Corsair H100 is much more effective in reducing idle temps, as the benchmarks illustrate.

TechRadar Labs

Idle temperature performance
X6 1100T: Degrees Centigrade: Lower is better
Antec Kuhler H2O 920: 28
Corsair H100: 20
Arctic Cooling Freezer 13: 33

Load temperature performance
X6 1100T: Degrees Centigrade: Lower is better
Antec Kuhler H2O 920: 34
CORSAIR H100: 34
Arctic Cooling Freezer 13: 51

Fine tuning

The bundled software allows you to create and customise your own profiles, telling the cooler at which temperature you want it to hit a certain fan speed, allowing for some really fine tuning.

The default profile has some problems, though. We found the load to idle temperature recovery time took… well it just never really recovered. We stopped counting after four minutes.

The H2O 920 isn't nearly as effective at slower fan speeds, and bearing in mind there's a fairly deafening 54dB buzz when full blown, it's food for thought.

Once you've spent the time creating your perfect profile, the H2O 920 is a very effective cooler, and if your chassis won't fit the Corsair H100's giant radiator, this setup from Antec will see you right.

Be Quiet's Dark Rock Pro C1 is a well put together twin stack cooler with a huge cooling area. Designed with each stack comprising 44 nickel-plated aluminium cooling fins, this is a serious chip chiller.

The cooler uses seven 6mm heatpipes that run from the nickel-plated copper base plate and right through the two cooling stacks.

Sitting between each stack is one of the two 120mm SilentWing Be Quiet PWM fans used for cooling. Be Quiet claims they produce 57.2 CFM of air each and together only generate a quoted noise level of 25.9dB(A) at 1,700rpm – the fastest the fans spin.

Both fans run off a single four-pin PWM motherboard connector and each is already fastened in place with tensioned wire mounts.

Size matters

As a result of its sheer size, this is another CPU cooler that makes the first memory slot and even the second one a bit tricky to occupy. Certainly, using modules with tall heatsinks is out, but standard sized modules should be okay.

The Pro C1 doesn't seem to cool as well as it should. In our tests it couldn't beat Scythe's Yasya for cooling, and the Yasya only uses a single 120mm fan. Although it's still a big cooler, it's somewhat smaller than Be Quiet's monster.

You do get a nagging feeling that the Dark Rock Pro C1 should be doing better than it does.