Firstly, thanks to Akasa UK for sending the AK670cu for review. Akasa have been in the game for a good while now (since 1997) and consistently seem to supply quality cooling products at reasonable cost. Let's see if they can repeat that with the AK670.

The AK670cu is the first intel pentium4 cooler I have reviewed. Being a newcomer to the p4 platform I wasn't sure what to expect in terms of heat output - a friend of mine runs an extremely warm p4 2.4c so I was slightly worried when my 2.4c arrived. I started off, as most, using the stock cooler and was very pleasantly surprised by pretty much constant sub-30 temperatures. The stock cooler is also reasonably quiet. So, with this in mind, do we really need to replace it with an after market cooler? The many heatsink manufacturers obviously think so and the sheer shame of having anything "stock" in a system these days might be enough to convince many of us. I'd like to see something extra from any cooler I replace the stock cooler with, otherwise I don't see how it has any value. However cooling ability isn't the only driving factor today - with more computer cases on sale now having windows than not, you've got to brush up the appearance of your computer's interior. Most heatsink manufacturers have picked up on this new computer vanity and acted appropriately...

As is usual with Akasa products the packaging is bright and clear, fairly attractive I'd say. There's no overly boasty claims like "best cooler in the world", just information relevant to heatsink choice. As listed on the package, the specs are:

Copper base
83x69.5x38.5 mm heatsink dimensions
70x70x15 mm fan dimensions
3800 rpm fan speed
31.44 (a bit too precise..?) cfm air throughput
34.5 dB fan noise

As per fairly standard heatsink design the AK670cu consists aluminium fins joined to a solid copper lump at the base. Theory dictates the copper efficiently absorbs the heat produced by the core while the aluminium quickly dissipates it to the surrounding air (or into the air current as is the case when using an actively cooled heatsink such as this). The design is widely used so there must be something good about it.

Stuck to the base comes one of Akasa's self-revered Shin-Etsu pads. In my experience these pads do actually perform as well as most (even "high end") thermal pastes, meaning there's no need to spend extra money on a tube of arctic goop. The stuff can cost over a fiver a tube so factoring that into the cost gives the AK670 bonus points for value.

With these p4 coolers installation is generally very simple. The Akasa clip is no exception, a simple push of a lever applies the correct force between the heatsink and core. With the clip in the "up" position, the heatsink can be freely lowered onto the chip and into the retention clip area. Once in position, with the four clips loosely connected to the plastic retention clips on the motherboard, pushing down the lever secures the heatsink. Job done!

This heatsink unit includes a non-standard size 70mm fan with four integrated blue LEDs. The effect when illuminated is rather impressive, although I'm sure we've all seen LED fans before. A standard wire grill is secured over the fan for what I can only assume is finger protection - not that many people will be waving their hands around the CPU fan. Perhaps Akasa could include some specially designed fan grill for a slightly more impressive look, following the lead of Thermaltake with some of their coolers. Still, that would more than likely introduce extra cost.

Anyone who's read my heatsink reviews will know I'm not a great fan (hoho) of noise. As we've seen, the official line is that this heatsink is rated as 34.5 dB. Noise "ratings" on heatsinks are often very dubious and even with all the best intentions it's very difficult to give a quantitative measure of noise since particular conditions will always make differences. With other fans in the case all turned as low as possible, there is a noticeable whirr from the 670. I wouldn't call it loud as such but it's certainly not "silent" (as if anything could be). Since a non-standard size fan is used, it won't be too easy to replace it with a quieter model. Using a fan speed controller (or adding your own resistors) would be possible however.

When installing the cooler I tested the fan before entrusting my computer to it. Good job that I did because on first start up the fan refused to rotate. It turns out one of the LEDs was protruding into the path of the fan blades obstructing them. All it took was pushing the LED out into the outer casing with my thumb, but it's something some people might not think to check for. A very minor problem, but a problem nonetheless and something Akasa might want to look into - just a little dab of glue would have held the LED in position and stopped this from happening.

I guess it's time for some temperatures. The world of motherboard monitor hasn't caught up with my ATi motherboard yet (or it doesn't have the ability) so unfortunately the only source of temperature readings is the bios. I have been told that the bios puts the cpu under full load but I'm very sceptical of this so in an attempt to get fully loaded temperatures I stressed the CPU using superPI before resetting immediately and reading from the bios. The results are as follows:

"Normal" operation

"Full load"

Clearly these two temperatures are no different.I'd also been getting temperatures very similar to this using the stock cooler. I might have seen 31 or 32, but no more. This means the AK670cu isn't hugely ahead of the stock cooler in terms of performance. I do think it sounds a little quieter, or at least has a less intrusive noise, and of course there are the blue LEDs to consider!

From experience with Carl's p4 the temperatures seem to revert from load very quickly - this seems to be the case for me as well. Very strage. In the interests of science I hooked up my new Superflower Fan Master (review pending) to measure the temperature of the heatsink base. This showed slightly different results - around 32 degrees but rising to 40+ when gaming. It seems the temperature changes too quickly to get a measurement from bios and that I might have to invest in a better motherboard some time in the near future.

Much more like it - we can see that the temperature does indeed rise when the CPU is loaded, but it seems to drop off very quickly. Perhaps this is some wizardry on intel's part, something I will have to look up.

When affixing the temperature sensor I obviously had to remove the cooler whereupon I came accross a bit of a problem with the thermal interface. Removing it wasn't at all easy - it had made a very strong bond, so strong in fact that removing the heatsink actually pulled the CPU out of the socket even whilst it was "locked". This was pretty worrying, especially since I had to pry the heatsink off with a screwdriver. I had taken on board everything Akasa said about their TIMs and indeed it seems they do perform quite well, but if things like this are going to happen I think I will stick to my old tried ways of scraping them off and replacing with good old arctic silver. Shame really.

Time to sum up. Well, as a new intel user I'm impressed by the chip itself - for a processor at a 2.4GHz clock it runs at very low temperatures. As for the cooler.. compared to the stock cooler it's clearly not a whole lot different. Rather than this being a downer on the Akasa cooler in fact I was impressed that the stock cooler was so effective. The Akasa improves slightly on the stock cooler's performance but for those who have real interest in cpu temperatures or overclocking every degree counts.

If you've bought a pentium4 chip without the stock cooler (an OEM purchase or second hand perhaps) then the Akasa AK670cu would be a great cooler to pick up. Available for around £14 it's a great budget cooler that should suit most people. I can't see why anyone would need anything more powerful but I know for a fact that the "hardcore" won't buy such a cheap and simple looking cooler. They needn't really pay the extra.

Great value
Good looks
Well designed clip
Decent performance
Somewhat noisy
No fancy extras (manual/automatic speed control)
Doesn't offer a whole lot more than the stock cooler
Thermal pad leaves a stubborn residue

Related:
Akasa UK website.
Simply Computers, reseller.