XIREX Stealth Waterblock Page: 1
The rombus Group is a little known, but expanding IT company based in Büren, Germany. For more than 10 years now rombus has manufactured server-, notebook-, PC-systems and home entertainment products. Xirex, a subsidiary company of the rombus Group specialises in providing effective cooling hardware for today's high-end hardware. Let's hear a little of what Xirex has to say about themselves:
XIREX Liquidcooling department is committed in designing and manufacturing the best quality liquid cooling products, addressing a new market segment which is rapidly growing and is demanding products with high cooling performance, noise reduction and easiness of use/installation. XIREX Liquid cooling is all this, and much more.

XIREX Liquidcooling is constantly developing new solutions for the newest high end gaming and professional video cards, being the first to have developed a full liquid cooling system exclusively dedicated to high end professional graphic workstations, capable to deliver exceptional cooling performance, extreme low noise operation and outstanding quality and security for the hardware..
Xirex Steallth Waterblock
Today I have been fortunate enough to have been given the opportunity to review the Xirex Stealth Waterblock, which is an universal full copper wateblock for Intel Sockets 775, 771 and AMD Sockets 939, 940, AM2. Based on "flat cooler" technology, the Stealth promises exceptional performance at a very low price, compared to the competition.
Let's begin the review by taking a look at the Xirex Stealth's specifications...
Materials: completely made in electrolytic copper
Installation method: installation screws + nuts + washers + springs
Compatibility: INTEL (Sockets 775, 771, 478) and AMD (Sockets 939, 940, AM2)
Connectors: 2x G1/4" threaded holes (fittings not included)
Nothing out of the ordinary here so let's take a closer look at the review specimen on the following page...

XIREX Stealth Waterblock Page: 2
I received my Xirex Stealth Waterblock in a plain brown cardboard box which is typical for many review samples. However, I'm not sure how Xirex's packaging differs between review and retail versions of their products. Many manufacturers prefer to at least 'beatify' their products packaging by including at least a sticker identifying the product and a logo identifying the manufacturer.
Xirex Stealth box Xirex Stealth box_2
You'll notice the absence of any kind of protective material inside the box, but then again it'd take some serious knocks to do damage to an all copper waterblock afterall. Included in the Xirex Stealth's packaging were:
* 1 x Xirex Stealth Waterblock;
* Mounting hardware (springs, washers etc.)
* Thermal paste.
Xirex has decided to omit the inclusion of an installation manual in this review sample which isn't an issue, and according to their FAQ section on their website they do in fact include one in the retail version.
Xirex Stealth package contents
A Closer Look
The Xirex Stealth certainly looks quite striking in black and its built in universal adaptor plate is certainly a lot less likely to cause compatibility issues like some waterblock's out there. The copper base is nice and flat, but not without the inclusion of reasonably deep lapping marks.
Stealth top view Stealth copper base
The image below (left) further illustrates the amount of lapping marks present on the Stealth's copper base. The lower right image also illustrates the extremely low profile nature of the Xirex Stealth Waterblock.
Stealth copper base close-up Stealth side view
Stealth inside shot
The keen eyed amongst you would have noticed some irregularities present in both the inlet and outlet of the Xirex Stealth. To be honest, I'm not 100% sure what the odd build-up is but it certainly looks like leftover weld material where the brass inlet/outlet seats were attached to the copper block itself. Regardless, it doesn't look incredibly inviting and hopefully it won't diminish the potential cooling performance of the block.
Apart from a few little niggles the Xirex Steallth certainly looks like a sharp little waterblock, and hopefully one that performs as well as it looks. Let's head over the page to see how we're going to test the sample...

XIREX Stealth Waterblock Page: 3
Testing Method
A Laing DDC Pro pump with OCLabs alternative top will be used to assist in making a comparison. I shall be looking specifically at pressure drop, flow resistance and cooling performance from within a CPU only water-cooling loop. I will be running the Laing DDC Pro pump at 9v,10v, 11v and 12v and the pressure drop and flow of the pump will be noted. All tests will be run 3 times to ensure the elimination of any oddities. I have included the setup details below:

Pressure Drop

For the pressure drop test I used a 25L portable water container filled with 20 litres of water, with a 1/2" plastic threaded barb placed in the bottom to represent the reservoir. A stop tap was inserted immediately after the 1/2" barb to allow for a faster water-block change. The True-Flow pressure meter was used to record the head pressure per 1 minute testing cycle. The pump was primed and let run for a short period to ensure that no air bubbles were left in the loop.

The first run made was with only the pump and pressure meter included in the loop and the water pressure noted. Then for second run the Xirex Stealth Waterblock was included into the loop and the drop in loop pressure recorded, and the same procedure was done for each of the water blocks.

* 1 x Laing DDC Pro pump with OCLabs alternative top @ 9/10/11/12v
* 1 x Xirex Stealth and XSPC X2O Delta Waterblock
* 1 x Powertech variable DC power supply (quoted accuracy /- 0.2V)
* 1 x Multi-meter
* 25L portable water container
* 1 x Glycerine filled True-Flow pressure meter. (kPa/PSI)
* 1/2" ID XSPC tubing
* 1/2" barbs
* 2 x stop-tap fittings

In a similar test to the pressure drop testing above, the flow test will highlight just how much the waterblocks restrict the natural flow of a water-cooling loop. Utilising a very simple setup consisting of a pump, I/2" ID tubing, water blocks, bucket and a stopwatch we will see how far removed from the absolute flow of the pump, that the water blocks hinder flow. Incidentally, this is the same way that we test CPU blocks in past reviews...hence the included image below. Running the pump into the bucket for one minute and then measuring the amount of water pumped will be the 'absolute flow' of the pump. Once again the pump will be run at 9v,10v,11v and 12v.

To calculate the flow-loss or restriction of each waterblock, they will each be included into the loop (one at a time) and the same procedure followed. The flow rate will be recorded in Litres/ hour. All simulations will be run 3 times each to ensure uniformity of the results and an average then taken.
Loop Simulation and cooling performance

I have decided to impliment a control setup for the testing phase of this review. In doing so I have replicated a CPU only water-cooling loop similar to that in conventional water cooled setups, but also one that should return consistant and unbiased performance results. The Xirex Stealth and other waterblocks performance will be assessed at the Laing DDC Pro's operating voltage of 12 volts. For each run, the pump was allowed to run for 20 mins to ensure the evacuation of all air from within the loop. The temperatures were taken at 30 minute intervals to allow them to 'settle'. Two instances of ORTHOS will run simultaneously in order to simulate load.
Arctic Silver 5 was used as the TIM for testing all water blocks in this shootout I have recorded temperatures at idle, load and and an overclocked loaded state; all temperatures were taken using Core Temp 0.99 and water/ambient temperatures were taken using a common household mercury thermometer. The mercury thermometer was allowed 5 minutes to aclimatise to air and water and then the temperature recorded. The setup used has been included below:

* 1 x Laing DDC Pro pump with OCLabs alternative top @ 12v
* 1 x Xirex Stealth and XSPC X2O Delta Waterblock
* 1 x Powertech variable DC power supply (quoted accuracy /- 0.2V)
* 1 x Multi-meter
* 1 x Toyota Camry heater core
* 1 x Scythe Ultra Kaze 2000RPM cooling fan
* 1/2" ID XSPC tubing
* 1/2" barbs.
* 1 x Intel Q6600 SLACR G0 stepping quad-core processor
* 1 x ASUS P5B Deluxe wifi/App motherboard (bios version 1101)
* 1 Gigabyte 7600 graphics card
* Logitech generic mouse
* Logitech G15 keyboard
* 2GB OCZ PC2-6400 Titanium RAM
* Antec NEO EarthWatts 500W PSU

Please be mindful that all water block mountings were done so with a back plate.

Follow with me over the page to see the test results...

XIREX Stealth Waterblock Page: 4
Test Results
Pressure vs Flow chart
Temperature charts
We can see from the pressure vs flow chart that the Xirex Stealth is certainly more restrictive than the XSPC X20 Delta that it was tested against. That being said, the Stealth managed to perform better than I'd expected when we ran the actual cooling loop testing.  If Xirex were to include some micro-channels in the base of the Stealth and relieve some of the restriction present, we may see a significant reduction in the defecit between the two blocks. Regardless, the Xirex Stealth block performs quite well as it is, but just remember to factor in its restrictive nature when designing your loop by looking at the beefier Laing DDC Ultra instead of the Pro.

XIREX Stealth Waterblock Page: 5
So ho well did the Xirex Stealth CPU Waterblock perform in todays testing?
The Xirex Stealth is certainly an attractive waterblock and one worthy of a second look. The exceptionally low-profile nature of the block would lend itself well to those who prefer their cooling system to compliment the overall look of their rig, as opposed to completely overpowering it. Furthermore, the build quality of the Xirex Stealth is par for the course when compared to alternatives out there.
Cooling performance exhibited today was adequate for dual- and quad-core work, and whilst the Xirex Stealth was beaten in todays review by the XSPC X20 Delta waterblock, again, it's certainly worthy of a look if you're after a solid performer and not the best of the best.
Unfortunately I was able to find any retail samples for the Xirex Stealth anywhere in the UK or US, and subsequently a retail price for the waterblock was equally hard to come by. As a result I'm going to have to reserve my opinion on the Xirex Stealth's price until I receive confirmation from Xirex.
The Good
* Build Quality
* Cooling Performance (even on quad's)
* Looks
* Low profile
The Mediocre
* Restrictive
The Bad
* Nothing to report
OC3D Recommended Award
Overclock3D would like to thank Xirex for supplying todays review sample
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