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ID-Cooling IS-40 & IS-VC45 Review


ID-Cooling IS-40 CPU Cooler Heatsink-Fan

ID-Cooling IS-40 Top

A little over a month ago we posted the ID-Cooling IS-25i Review based on a test session we did including the IS-25i, IS-40, IS-VC45, Zalman CNPS2X, and Noctua NH-L9i. In that review the IS-25i showed impressive results compared to the Zalman CNPS2X.

Today we bring you the second part of that write up: comparing the ID-Cooling IS-40 and IS-VC45 to the Noctua NH-L9i.

These CPU Coolers are in a larger size category than the Zalman CNPS2X and ID-Cooling IS-25i. The smaller CPUs we use with our 60mm cases, while the larger ones are destined for our 80mm cases.


ID-Cooling IS-40 Bottom

ID-Cooling IS-40 Bottom


ID-Cooling IS-40 and IS-25i Side-by-Side

ID-Cooling IS-40 & IS-25i Side-by-Side

As you can see the IS-40 is significant larger than the IS-25i and features a 92x15mm fan instead of the 80x10mm fan on the IS-25i.

CPU Cooling has a few major components to it:

  • Conducting heat away from the CPU to the heat sink fins
  • The surface area of the heat sink fins
  • The air flow over the heat sink fins
  • The ambient temperature

In a CPU cooler with heat pipes the heat pipes conduct heat away from the contact area with the CPU to the heat sink fins.

The greater the surface area of the heat sink fins the more heat can be dissipated into the air.

The larger the fan and the faster it moves the more air can be passed over the fins.

The lower the ambient temperature is the easier it is for heat to be transferred from the fins to the air being blown over them.

Every one of these components is a limiting factor, so the overall cooling solution will only perform as well as its weakest component.

In general a larger heat sink will perform better because it has greater surface area and a larger fan that pushes more air.

Additional heat pipes facilitate more rapid conduction of heat away from the CPU to the rest of the heat sink, but the surface area of the heat sink, capacity of the fan, and ambient temperature can still be a limiting factor.


Testing Procedures

The components used in this test were an ASRock Z97E-ITX/ac, an Intel Core i7-4790S CPU, and 16 GB DDR3 1600 Memory. We used an EVGA 430 Watt 80 Plus power supply for testing.

We performed these tests using the Xubuntu 15.04 Linux operating system. We used the lm-sensors package to monitor temperatures and we used Prime95 to stress test the CPU and cooling solutions.

These tests were performed with an ambient temperature of roughly 35C (95F). This is higher than the typical operating environment for a computer (72F, 22C) so under normal operating conditions you would lower resulting temperatures.


Noctua NH-L9i

Noctua NH-L9i


ID-Cooling IS-VC45

ID-Cooling IS-VC45

One important thing to note here is that the heat sink placement for the IS-VC45 in this picture is wrong! The open sides of the fins need to be aligned towards the most open area so that air flow from the fan, which blows down, can move unimpeded.

If you look at the positioning of the Noctua NH-L9i that is correct.

I did a round of testing as pictured with the IS-VC45 and then realized my mistake and corrected it which yielded a much better results. All of the results here are based on testing with the correct placement.

In a case this tight where the heat sink is almost flush with the RAM correct positioning will make a major difference in cooling performance.


ID-Cooling IS-VC45 Top

ID-Cooling IS-VC45 Top


ID-Cooling IS-VC45 Bottom

ID-Cooling IS-VC45 Bottom

The ID-Cooling IS-VC45 uses a vapor chamber in the base as opposed to heat pipes in order to conduct heat away from the CPU contact area to the heat sink fins.

A vapor chamber is similar to a heat pipe in that it utilizes liquid sealed inside a chamber to conduct heat rapidly from one place to another.

As you can see from the photos the IS-VC45 is a very nicely machined product with a solid build and mirror finished CPU contact area.


Prime95 Torture Testing

In order to really stress these CPU coolers we not only conducted testing in an extreme environment we also ran the Prime95 torture test utility at 100% on 8 threads, fully utilizing the Intel Core i7-4790S CPU.

Prime95 will use different amounts of power, resulting in different levels of heat output, depending on the FFT length selected.

With a 320K FFT Length the system uses about 90 Watts at the wall, while with an 8K FFT length power usage jumps to 116 Watts.


320K FFT Test Results

  Fan Speed FFT Length Idle Temp
Max Temp
Time to > 80C Time to Throttle
Noctua NH-L9i 2700 RPM 320K 41C
ID-Cooling IS-40 3100 RPM 320K 40C
ID-Cooling IS-VC45 3100 RPM 320K 41C 71C N/A N/A


Running Prime95 with a 320K FFT length all 3 of these CPU coolers were able to handle the load much better than the Zalman CNPS2X and ID-Cooling IS-25i.

The additional size does pay off with significantly better cooling results.

In this test all of the CPU coolers give roughly the same performance. The ID-Cooling IS-40 had the lowest recorded temperatures but these are within the margin of error for our test setup.


8K FFT Test Results

  Fan Speed FFT Length
Max Temp
Time to > 80C Time to Throttle
Noctua NH-L9i 2700 RPM 8K
8 Minutes 9 Minutes
ID-Cooling IS-40 3100 RPM 8K
8 Minutes 11 Minutes
ID-Cooling IS-VC45 3100 RPM 8K 82C 8 Minutes N/A


When Prime95 runs in blend torture test mode it starts with 320K FFT and then switches to 8K FFT at around 7 minutes with this setup.

The times here are from the start of the test.

While all of the CPU coolers made it through the 320K FFT round as soon as the test switches over to 8K FFT it is only minutes before they go over 80C.

The ID-Cooling IS-40 held up a bit better than the NH-L9i but they are very close.

The ID-Cooling IS-VC45 however did significantly better than both the heat pipe based designs and was able to hold up throughout the test without throttling.

ID-Cooling does say that the IS-VC45 is recommended for higher TDP CPUs and it does in fact seem that it scales better the more heat you throw at it, even though it does not perform noticeably better at lower loads.



All 3 of these CPU coolers perform well and are good choices for this size category.

The ID-Cooling IS-40 is the clear winner if you take into account both price and performance. The IS-40 can be had for $18.00 current if bought directly through eBay compared to around $45 for the Noctua NH-L9i and the IS-40 was the superior performer by a small margin in our testing.

The IS-VC45 is a very nice CPU cooler and it does show a significant edge under heavy loads in our testing, but at a price of $47 that small advantage may not be worth the extra cost.



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