Larkooler iSkyWater 300 DIY 240mm Kit

Posted: February 24, 2013 in Kits
Tags: , , , , ,

Welcome to the third in my series of 2x120mm under $150 value series kit reviews, the Larkooler iSkyWater 300. Larkooler is a fairly new brand to me as I haven’t had a chance to review any of their parts or pieces individually. Unlike the XSPC kit which left me running to the grocery store to get distilled water, this kit is complete with fluid and everything you need to put your system together. Also unlike the sealed AIO units such as the Corsair H100i which are sealed and not intended for expansion, the Larkooler iSkyWater 300 is DIY and there are VGA block and Ram block accessories intend to go with this kit for expansion possibilities. Also unlike the sealed kits where tubing is already connected and sealed, the Larkooler kit comes with external radiator mounting brackets and designed to be mounted internally or externally depending on your case needs. At $129.95, that makes this kit extremely low-cost, compatible with most cases if external mounting is desired, and expandable which we all like. We’ll put it to the test in this next review and see how it stacks up to similarly prices 2x120mm radiator sub $150 water cooling kits.

Before going to far, I would like to give special thanks to Mark from FrozenCPU for sponsoring this kit, they are your one-stop-shop for all PC modification supplies!



FrozenCPU Product Information

Product Description

Larkooler is a new generation cooling system for desktop computers. It is designed with the best cooling solution for the most important component of your PC, the CPU. This kit includes everything you need to get started. A pure copper block for maximum heat absorption. One 24cm radiator with two 120x25mm fans. Last is the tubing and cooling fluid. The VGA, Chipset and Mosfet blocks can be added to upgrade performance. The iSkyWater 300 provides a reliable low noise, high performance liquid cooling system. Literally every EVERYTHING you need is here in this kit!

Instructions Manual (.pdf)

Specification Sheet (.pdf)

Note: Radiator color is now black.

  • Most Cost-Effective CPU Liquid Cooling
  • Very High C/P
  • Supports INTEL LGA775/LGA1156/LGA1366/LGA2011
  • Supports AMD Socket 754/939/940/AM2/AM2+/AM3
  • 3D Micro-Structure Thermal solution adapted, outstanding heat dispersion under very low water flow.
  • Supports most CPU like Intel i7& AMD Phenom II processors.
  • The universal type strengthened backplate not only prevents MB distortion but also has high compatibility for all kinds of MBs.
  • Easy installation due to 2-way tubing design which also enables upgrade to series connection of more water blocks.
  • Highly polished base to ensure excellent surface contact with heat source.
  • Fitting with refrigeration-and- air-conditioning-class structures provides high performance heat dispersing at low noise.
  • Easy installation design and back mounting bracket let DIYers enjoy DIY.
  • Specially designed bolts and nuts to prevent tube’s looseness and coolant leakage.
  • Pump with refrigeration-and- air-conditioning-class structures provides low-water warning.
  • Steady and silent working.
  • Easy installation design brings more fun to DIYers.
  • Specially designed bolts and nuts to prevent tube’s looseness and coolant leakage.
  • Thread upgradable to be compatible with G1/4″ water cooling system
CPU Water Block
Dimension: D45xH29mm
Weight: 180g
Material: Pure Copper
Dimension: 100x70x82mm
Rated Voltage & Current: DC12V/0.41A
Weight: 330g
Flow Rate: 72L/Hour
Max. Water Lift: 200cm
Dimension: 35x124x302mm
Material: Copper tubes with aluminum fins
Fan Speed: MAX 1800 RPM
Fan Connector: 3 pin
Fan Max. Air Flow: 62.7CFM
Noise: 31.1dBA
Life Expectancy: 50000 hrs at 25°C
Capacity: 150ml
Main Composition: water & propylene glycol
Volume: 250 ml
Anti-freezing: -5°C
Dimension: OD8mm / ID 6mm
Length: 200cm
Material: PU
Max Operation Temperature: 50°C
Intel: LGA775/LGA1366/LGA1156/LGA2011
AMD Socket: 754/939/940

Description/Spec Thoughts

One of my initial worries was seeing the aluminum fins thinking the radiator was aluminum, but it is NOT. The radiator uses round copper tubes with aluminum fins pressed over the round tubes, but the critical part contacting water is all copper. The block is also copper, so no worries about mixed metals, the kit is all good copper/brass metals.


The pump has a good 2m head static pressure rating, however the 72LPH max flow rating converts to .26GPM, so it’s more of a high pressure but very low flow pump. At the rated .41Amps that makes this about a 5W max pump which is a good amount of power compared to AIO sealed units which are down in the 1-2W range. We’ll see how it does in operation. I did find this searching the net:

One more pretty cool feature in looking over the box, is the pump has a “Low Water Level” warning function, and of course you could easily connect multiple pumps in series as they show below:

Fitting Compatibility

The other “Mostly” good feature is the G 1/4″ threading compatibility. This is great for the block and radiator which all include the standard female G1/4″ threading so you can use your own barbs, BUT…the pump does not. The pump has male cast 6mm ID barbs with compression fitting threads which are intended to fit 6mmID x 8mmOD tubing. So you are a bit stuck with the smaller tubing size and fitting style with the pump, but the rest of the system could utilize custom fittings.

CPU Block

Digging further on the CPU block I actually found “SCIENCE”!! This does show how the block is very capable at very low flow rates:


For Reference: 1000ml/min = 0.26 GPM

Case Compatibility

Also not really advertised in the specs, but something I really like is their external radiator mounting brackets. For users who have a small case that may not support a 240 radiator, they give you nice brackets that could be used to install a radiator externally to the back or top of the case which increases case compatibility significantly.



The radiator has a 50,000 hour lifespan. The Warranty period at 1 year is also a bit less than the H220 3 year warranty or Corsair’s H100i 5 year warranty.

That’s not to say warranty matches actual service life, I just prefer seeing pump MTBF ratings and warranty for a few years.

Overall, quite a bit here to review and some promising specs and features for such a value priced kit. We’ll start next with the unboxing.


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  1. M3TAl says:

    Churning out these reviews like a well oiled machine Martin!

  2. Sounds pretty “meh” compared to the H220 & XSPX kits, great to have a basis for comparison like this though, thanks Martin! Email notification of new posts still doesn’t work for some reason…

  3. Lutfij says:

    Interesting to come across this kit – not a fan of it though 😛

  4. Steve says:

    Nice review so far Martin, again Thanks Much for your work on these DIY kits as it makes purchase decisions much easier. Personally I don’t think it is in the same league with either the 750 or H220 for comparable cost, just my thoughts from what you have done thus far.

    FCPU is still offering the Rasa 450 for $20 cheaper, it looks like this kit perhaps is more in line with that one on thermal performance maybe. The few that have left reviews there seem happy with them, but they are a bit mixed. They say Tom’s Hardware have given them an award of some kind, I could not find anything there, only a few post in the forum area. Tom’s is my go to place for hardware just like you are the go to place for WC, he did a piece on the H220 and spoken well as per performance/expandability/price of it a long time ago, they don’t do much on WC there as it’s a value oriented site and air still beats AIO per cost/performance.

    I like the internal pump/res setup, it saves bay area in smaller cases. From your pictures though it does not look very well built for longevity and the small ID fittings built in don’t seem like a real good idea. Wish XSPC would make an internal setup for their 750 and small reservoir as an option.

    It is lagging the H220 and 750 by around 10 degrees, do you think it is the pump, block fit to CPU or the much different radiator design with round single pass tubes? Or maybe a combination of all 3?

  5. bassboykevlar says:

    Horrible performance aside, that radiator looks AWESOME. Or is it just me?

  6. Martinm210 says:

    I really like the look of the radiator myself. I suspect my performance issue is mostly due to mechanical contact on the large 3930K. In past experiments with prototype blocks I have seen upwards of 5c gains from mechanical contact alone and the looks of the TIM spread suggests the extreme bow of the base could very well be the problem. I might try lapping the block later to flatten the base a bit and see what happens after phase 1 and 2 are done. Mechanical contact is everything anymore.

  7. bassboykevlar says:

    Maybe later on down the road when you’re pretty much done with all the testing phases you can switch out the xspc or swiftech radiator with this larkooler and use the xspc or swiftech block to see what kind of performance difference there is.

  8. Steve says:

    That’s a great idea bassboykevlar, it would sure find the leak link in the loop. The radiator does look pretty cool and seeing if it worked as well and a more “traditional” style would narrow it down a bit.
    Could put the 300 radiator in the H220 and 300 block in the 750 and test both, that would tell you which component was weak, if both tested around 70 then it would be something with the 300 pump.

  9. Tingez says:

    It does seem that the large CPU size causes some contact problems. It will be interesting to see the results you get from Lapping. Love the reviews nice to see someone actually taking time and care to find the real world performance levels and impart some useful know how too.

  10. Martinm210 says:

    Thanks. Yes, I could do some idividual parts testing. I could also add in some water temp sensors to measure water/air delta. I can also do some hudraulics test such as pressure drop of the kit in whole and pump or sustem PQ remaining using pressure differential and flow rate tools I can use arter this phase 1 testing is all done. For the stock kit vs kit I just wanted to test completely stock if possible as the first step then start in on the fun stuff..:)