Swiftech H2O-Apex “Extreme Duty” Watercooling Kit

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Kit Test – Joe

SUMMARY: Worth serious consideration for anyone looking for the best kit around

The good guys at Swiftech were nice enough to send a sample of their H2O-Apex “Extreme Duty” Watercooling Kit to test out. This kit was designed by Bill Adams for top performance – this alone signals something special.

The H2O-Apex will handle just about any CPU:

  • Intel socket 478 (Intel ® Pentium ® 4)
  • Intel socket 775 (Pentium ® 4 “Prescott”)
  • Intel socket 603-604 (Intel ® Xeon ™ except “Nocona” class processors)
  • AMD socket 462 (AMD ® Athlon ®, Duron ®, XP, MP)
  • AMD socket 754, 939, 940 (AMD ® 64 bit processors)

The kit arrived in a cardboard box packed with goodies:

SW Kit

I’ll unpack the kit and give you a tour of what comes with it.

The waterblock is the STORM Extreme Performance Universal Waterblock:


The Storm arrives un-assembled and with enough mounting hardware to open a Home Depot:

Storm Parts

You decide which nipples to install – the choice is 3/8″ or ½” barbs; for this test, I used the ½ barbs – use a wrench to install – hand tightening is not sufficient. I must say the Storm is one of the prettiest waterblocks I’ve seen – without the nipples, it almost looks like a hot-rod:


The base is typical Swiftech:


Anyone trying to improve on this with hand-lapping is going to be sorry – it’s about as good as it gets.

This is a high pressure drop waterblock which features a plate of 35 jets to direct water into individually matching cups. This means the waterpump used to drive the system has to be fairly powerful; included in the kit is the MCP655 ™ 12 volt waterpump:


Included is all the mounting gear needed to fix it in place and keep it quiet.

The pump’s specs are hefty:

  • Nominal power @ 12 volts: 24 watts
  • Maximum head: 10 ft (3.1 m)
  • Maximum discharge: ~ 317 gph (1200 lph)
  • Maximum pressure: 50 psi
  • Connection size: ½” barbs

This is no lightweight by any means. One notable feature on the pump is a potentiometer which adjusts the pumps speed from 4800 rpm down to 1800 rpm:

Pump Rheo

In some respects this maybe is a nice-to-have, but I did not hear any pump noise at full throttle to justify lowering the rpms; in addition, considering that the best performance for this waterblock requires waterflows over 1 gpm, I don’t know why you’d consider lowering rpms with a performance kit. Careful mounting with the supplied sound insulation should be sufficient (also, every time you want to change rpms, you have to access the back of the pump and change the potentiometer – not the handiest thing to do).

If however you want to change rpms, the following graphs from Swiftech indicates the tradeoffs:

Pump Spec

Graph courtesy of Swiftech

The radiator for the system uses Swiftech’s “Radbox”, which is an mounting kit which using the existing 60mm, 80mm, 92mm, or 120mm fan mounting holes to install the kit’s radiator with two 120 mm fans:


Fan Specs: Delta WFB1212M @ 12 volts: 2100 rpm, 72.4 cfm, 34.0 dBA

Included with the fan hardware are two plugs with resistors which allows the fan to run at 7 volts – the “low noise” solution.

Rounding out the system is the reservoir:


This is designed to mount in a CD ROM bay at the system’s highest point – this facilitates filling and maintenance; tubing and algaecide are included:


The Test

Swiftech’s H2O-Apex Watercooling Kit was tested using the CPU Die Simulator; I ran the fans at 12 and 7 volts using the resistors supplied with the kit.


Die Temp

Ambient Temp


Fans @ 12 volts, 57 dBA¹




Fans @ 7 volts, <50 dBA¹




¹Manufacturers measure fan noise at 3 feet from the fan; I measure at 8″ from the fan – 50 dBA is approximately equal to 30 dBA shown by manufacturers.

Test Results place Swiftech’s H2O-Apex Watercooling Kit at the top rank if watercooling kits tested to date (HERE). The noise level at 7 volts is very low and at 12 volts is noticeable but certainly not obtrusive. The performance hit for running at 7 volts is a minimal 2ºC.

In addition, I did test this kit on a large die (one inch square) which resulted in a C/W of 0.08 (fans at 12 volts) and 0.10 at 7 volts. This is not exactly comparable to the P4 testing I’ve done but it’s reasonably close, so P4 performance is outstanding.


Swiftech’s H2O-Apex Watercooling Kit is a high-quality all-in-one watercooling system that will deliver top performance – you can’t beat the convenience of having everything in one package that works well together with the flexibility to cool just about any CPU – worth serious consideration for anyone looking for the best kit around.

Disclosure: Joe Citarella has a financial interest in a company developing thermosyphon products for electronic chip cooling.

Email Joe


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