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Coolermaster HAC-V81
It's been a good few months since we last looked at a heatsink and when our top guy at Coolermaster sent us word of their new cooling unit we were interested to see how it performs. Coolermaster have a huge OEM presence and although their retail products haven't always performed as well as one would have hoped, they have always tried to innovate. Earlier this year they seemed to be onto a winner with their updated heatpipe design, which not only looked good but performed brilliantly. Updating the design further to incorporate a low noise fan, Coolermaster catered for both the die-hard overclocking community whilst not forgetting the noise conscious user. The HAC-V81 is aimed at providing that level of performance but with price and noise in mind.

About 18-20 months ago all copper heatsinks become the popular choice for overclockers and enthusiasts alike. Copper is known to have better thermal properties than aluminium and although this meant a rise in prices, the performance increase dealt by these units resulted in many consumers willing to pay this premium.

Copper embedded heatsinks have been around for a number of years now, with Alpha being best known for fashioning this technology. It allowed Alpha heatsinks to have some of the advantages present in a all copper heatsink but kept the costs down by only using the metal where it is required.

It's a formula that worked and sold well. We looked at the Alpha PAL6035 some years ago and it proved to be one of the most popular heatsinks of the day, with supply not able to keep up with demand. Coolermaster took this idea on board and produced their first heatpipe cooler, which had a copper base and heatpipe. It which worked well however due to an underpowered fan the CH5-5K12 was let down at the final hurdle. Coolermaster persevered with heatpipe technology and earlier this year they launched a revised product which, although noisy had performance and looks which won the day. Later they released a "silent" version.

So why release the HAC-V81? Well, this is what we were told when they first announced it a few weeks back :-
  • Special design fan grill to maximise air flow in and reduce turbulence
  • Variable speed fan
  • Copper base
  • 6 point clip

  • Also it uses a new manufacturing technology. The codename for this cooler is the XDream (certainly preferred over the HAC-V81). Coolermaster have, unlike most other manufacturers put some effort in packaging too. Featuring oversized plastic containers which describe their product specifications along with giving instructions on how to install the cooler. A fair amount of equipment included with the XDream since it has a variable fan speed controller but all things considered the packaging is better than most.

    Opening the packing reveals the wiring for the rheostat. This varies the voltage going to the fan thus allowing different fan speeds. It isn't the neatest job in the world, however once placed in it's holder and with the cap on it looks smart enough.

    Looking at the main features in turn :-
    Fan grill - Most see fan grills as a finishing touch, but sometimes they are a necessity. These days 80CFM fans require them for safety, however with such high volumes of air being moved any obstructions can cause not least a decrease in airflow but an increase in noise. Coolermaster's black plastic grill is there for show (the gaps are still wide enough for your fingers to get through), but due to the increased spacing between rails it does help air to flow in between with less obstruction. You have the option of removing the grill altogether if you feel so inclined.

    Variable speed fan - this feature really became popular after Thermaltake introduced it in their Volcano range and unsurprisingly other manufacturers caught wind that it really was a good idea to allow users to set fan speed at their discretion. The main advantage of allowing the fan's speed to vary is a reduction in noise. There is no doubt that faster fans result in better cooling, however at times when you are doing non-CPU intensive tasks like word processing or running Winamp you can cut down on the amount of cooling required and still get away with a stable system. Another factor is that the lifetime of the fan is extended if it isn't run at it's limit all the time. This is of utmost importance to machines that are constantly running, since a fan failure can result in disaster.

    To this end Coolermaster have included a dial which slots on a spare expansion slot and allows you to control the fan speed. It works well, however it would have been nicer (and easier to operate) if it could be mounted at the front of your case rather than the back. Maybe future Coolermaster cases will have this feature.

    Copper base - we already discussed this in the introduction, but to say the whole base is made from copper is false. The key section of the base, which makes contact with the CPU core is made from copper and it is fairly thick copper. Almost impossible to measure accurately, however from visual inspection the copper ingot rises above the aluminium so we can say it's around 1cm thick copper. Doing some elementary maths we worked out the volume of copper to be around 7.1cm cubed. One has to be cautious about the interface between the copper and the aluminium. If there isn't a good thermal interface between the two metals this could spell disaster. We expect a seasoned manufacturer, like Coolermaster not to get it wrong. We'll see if they have a little later on.

    6 point clip - We loved the clip in the previous Coolermaster heatsink we reviewed - it was easy to handle, however it didn't use all the retainers on the socket. Coolermaster listened to the community and made the change. They kept their patented "swivel device", allowing you to easily remove the heatsink but have put the added bonus of a 6 point clip which lowers the pressure put on the traditional middle socket clip. Thanks for listening Coolermaster.

    Taking a closer look at the base we see that it's not as smooth as some would like. A very grainy surface which really needs some attention given to it in order to get the best performance from it. Of course one can argue that good thermal compound should take care of surface blemishes, but there's no substitute for hard work (or so they say).

    Installation is very easy thanks to the 6 point clip, however should you falter Coolermaster have provided some concise instructions on the back of their packing. They also supply you with a sachet of white thermal grease, which looks to be silicon based. Coolermaster have taken the wise decision of not supplying their XDream with a thermal pad fitted as standard.

    Our tests were conducted on a system comprising of the following hardware :-
    AMD Athlon XP 2000+ (1.67Ghz) CPU
    EPoX 8K3A+ motherboard
    512Mb Kingmax TinyBGA PC2700 RAM
    Coolermaster ATC 710 case (2 CPU exhaust fans, 2 intake fans)
    Arctic Silver 3 compound
    Other heatsinks used in this comparison : Coolermaster HHC-L61, Globalwin CAK-II 38 and Swiftech MCX462-B. The Globalwin CAK-II 38 had a 7000 RPM, 38 CFM fan installed, the Coolermaster HHC-L61 had a 3000 RPM, 14 CFM fan and the Swiftech MCX462-B had a 40 CFM fan.

    Initially we tested the XDream with the fan on it's lowest setting.

    Maybe surprisingly the XDream performs worse than all other heatsinks, however we have to remember that with the fan at it's lowest setting there is only 31 CFM flowing and this isn't an all copper unit. Next up we turn the fan up to full speed, producing over 62 CFM.

    Clearly having the CFM advantage over the competition, the XDream performs well although it just falls behind the massive MCX468 from Swiftech.


    Coolermaster has produced a product that for the first time in a long while gives users the best of both worlds for a price most can afford. Aggressively priced at 18 including VAT the XDream isn't as refined as previous products we've seen from Coolermaster, however the basics are there and with a little tinkering you could be looking at a very good cooling solution for under 20 quid.

    The inclusion of a 6 point clip, variable fan control and a thick copper insert in the base makes it very good value for money. Some might prefer to use some sandpaper and smooth the base down a little; left as it is, the XDream performs just above par with the big boys and below par when the fan is given the chance to show off itself. The XDream has the price and the performance to get our recommendation.

    And finally, what has become the standard finishing punchline for heatsink reviews here at UK Gamer - our size comparison.