Verdict

The whole concept of using water to cool the innards of the PC is still considered by many to be slightly extreme with no place in mainstream computing. Part of this no doubt stems from the ingrained knowledge that when water comes anywhere near electricity it’s certain to end in tragedy, a perfectly understandable fear though not necessarily an accurate one.

Believe it or not there was actually a time when the idea of fitting a fan to a CPU was seen as extreme but the evolving PC began to make new demands and as a result previously extreme measures became an essential part of day-to-day computing.

Although it’s by no means new, water cooling has remained a fringe activity for longer than most, but with CPUs getting ever hotter and the requirements to air cool them efficiently are getting ever noisier. Manufacturers are now looking for ways to make water cooling cheaper, easier and safer to use while at the same time making it more accessible to the less adventurous PC user. The Silent Stream is just one of many self-contained water cooling products that have appeared on the market all clearly targeted at the less experienced user, but what makes the Silent Stream so unusual is its remarkably compact design.

All water cooling systems share three basic ingredients. First there’s the water block which sits on top of the CPU and transfers heat away from the die and into the water flowing through it. At the opposite end of the circuit is the radiator where the reverse happens as heat from the water is drawn into the radiator’s fins, which are then cooled using airflow from a fan attached to it. The final ingredient is the pump, which is required to keep the water circulating between the water block and the radiator.

Although all water cooling kits offer a variation on this theme the Silent Stream differs radically from the norm in that the pump has actually been incorporated into the casing of the water block itself. This is achieved by mounting a small motor on its back which then drives an impellor inside the casting of the block by means of a magnetic coupling. The use of a magnetic coupling rather than a mechanical drive shaft means that there are no O-rings and of course less risk of leaks. It has always been advisable to use distilled water in any water cooling setup but the small size of the impellor and motor assembly could well make this one particularly vulnerable to the build-up of mineral deposits and for this reason I’d strongly suggest that you only ever use distilled water with the SilentStream.

One sacrifice made in order to keep the Silent Stream as simple and compact as possible is the reservoir. The total absence of a separate external reservoir means the Silent Stream holds a mere 50cc (50Ml) of water even when filled to capacity. This means that the water gets little time to rest and cool as it’s either at one end soaking up heat, at the other end giving up heat or somewhere en-route between the two. This not only demands that all the components be efficient and well balanced, but it also means that with so little spare water capacity even the slightest leak or source of evaporation could prove catastrophic very quickly indeed.

The tube standing proud from the water block is a bit of an enigma. Other than serving as a kind of small-scale integrated reservoir of sorts it seems to have very little real purpose in life. It does feature two white markings which I can only assume denote the minimum and maximum water levels. This would all make perfect sense but for the fact that when used in a tower case the tube would actually sit horizontally, thus rendering any quick visual water level checks impossible. This is a major weakness as it means all but desktop case users will need to lie their case over on its side in order to accurately check the water level, hardly a user-friendly feature. At the top of this tube is a screw-on filler cap inside which sits a green LED. As a power indicator this LED’s usefulness is limited to those with a side window in their case in order to see it, and as a form of illumination to facilitate checking the water level it’s pointless to all but users of desktop cases as I just mentioned, so once again it seems to be a feature with no obvious purpose. It looks pretty in the dark though.

The motor and LED combined use around 0.46A so connection directly to just about all recent motherboard fan headers is fine.

The filler cap seals on the tube by means of a very thin O-ring that looks like it wouldn’t take too much abuse. A spare would certainly have been welcome. Also the thread on the filler cap and tube are quite shallow and could easily be stripped if tightened with too much force.

The base of the water block comes with a copper slug pressed into the otherwise aluminium casting. A quick check with an engineering rule showed everything to be flat and true, important for maximum contact with the CPU. A small tube of thermal interface material is supplied for use between the block and CPU die.

The kit comes with provisions for fitting to either AMD or Intel socket based systems. In both cases installation was quick and secure.

Because the Silent Stream arrives pre-assembled and pre-filled, the easiest option is to mount the radiator/fan assembly inside your case. However, this impacts on performance as the warm air inside your case is being used to cool the water in the radiator. The manual also suggests that you break out the tin snips and cut away the fan grills so as to eliminate any possible restrictions to airflow.

A more efficient method and one that GlobalWIN says is preferable is to mount the radiator/fan outside of the case. This is also the more difficult option as it means draining the water in order to remove the feed and return pipes and thread them through two pre-drilled holes in the supplied blanking plate. Once this is done and the pipes are refitted it’s then necessary to activate the pump and refill the system but without actually booting the computer. This is achieved using a small device that fits into the ATX power plug and allows the power supply to become active while removed from the motherboard. Once the system is filled and all air bubbles removed the ATX power connector is plugged back into the motherboard and you’re ready to go. It’s not rocket science but I can’t imagine that many inexperienced PC users would relish tackling the job.

The Silent Stream uses very flexible and extremely strong Silica water pipes which makes routing them a simple task. They’re also very heat tolerant and attach to both the block and radiator using a patented clip less design which seems like a great idea until you need to remove a pipe at which point you begin to wonder.

The radiator is a small but good quality all copper unit with a good surface area to the fins. It is coupled with a fairly quiet 32dBa, 38.88CFM fan. It’s an 80 x 80 x 25 (WxHxD) fan with a 3000rpm spin speed and both a ball and sleeve bearing.

Verdict

All told the Silent Stream offered surprisingly solid cooling performance for such a compact design, though later testing has shown it to be particularly sensitive to general ambient room temperature quickly becoming less impressive as the room temperature rises.

The difficulty with the Silent Stream lies in knowing who it’s targeted at. The design problems concerning checking and topping up water levels and the reduced performance when the radiator is installed internally make it hard to recommend for the novice user, who can get similar performance from a mid to high end air cooler at a similar price. Find one powered by an 80mm fan and even the noise advantage is nullified.

The more advanced user is also unlikely to be wowed by the Silent Stream due to its relatively small radiator, its low flow rate and the inability to use alternative water blocks. I should imagine a slightly slimmer version for cooling video cards would go down well though.

Perhaps the most obvious market for the Silent Stream is the small form factor PC user who would not only get the benefits of water cooling without needing to site a separate pump and reservoir, they’d also be able to install the block the correct way up and use it as it was intended. Even here though things aren’t as simple as they seem because of the three small form factor PCs I tried only one had room to accommodate the long filler tube.

At £88.12 from Rainbow Components Ltd, the price isn’t particularly enticing either.

There are several water cooling kits available at this price point which offer comparable performance and greater flexibility though ultimately none are quite so compact or easy to install.

Despite the seemingly endless negatives the Silent Stream isn’t all bad. The idea is a good one and it’s one that deserves to be developed further. With a few design rethinks and a slightly keener price this could easily find its place among the realms of mainstream cooling products but for the hardcore user I fear it will never be bought for anything but very specific projects where space is at a premium.

Testing carried out using SiSoft Sandra 2004 Burn-In wizard. CPU tests were configured to load CPU to 100% and 35 test cycles were completed in an ambient room temperature of 16 degrees Celsius.

”’Test Setup”’

Epox 8RDA3G Motherboard

AMD AthlonXP 3200+ (Barton)

Radeon 9800 Pro

Corsair TwinX 3700

WindowsXP Pro + SP1

”’NOTE”’

Since this review was written I’ve learnt that GlobalWIN has dropped the rigid filler tube idea in favour of a longer, flexible filler pipe. This not only addresses some of the issues I raised over its questionable usefulness, it also makes filling possible regardless of orientation. Being longer, the tube also serves to slightly increase the total volume of water held by the SilentStream and GlobalWIN suggests that water level checks need only be made every couple of months. That said, I personally believe weekly level checks are a good habit to get into no matter what form of water cooling you use.

”’Update”’

TrustedReviews has been informed by Rainbow Components that the price has been changed since we initially got the review unit sent in. The Price has now been changed to £75 inc VAT. This does have some impact on the overall review, but it doesn’t change the reviews view on the unit as a whole.

We have also been informed that the changes made to the filler tube were influenced by feedback on the review samples that GlobalWin has sent out. This shows that feedback in terms of the functionality of a product can have an impact on the manufacturer to the degree that the needed changes are done before it is released to the public.

Trusted Score