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[nextpage title=”Introduction”]

Some months ago we tested an excellent cooler from Zalman, CNPS10X Extreme. Today we are going to review another cooler from the same family, CNPS10X Flex. Will it perform like its brother? Let’s see.

The name "Flex" stands for "Flexibility", meaning that the cooler doesn’t come with a fan, allowing the user to choose the fan that best fits his or her needs.

The box is simple, with dark and blue shades.

Zalman CNPS10X FlexFigure 1: Box.

Inside the box we found the cooler, installation hardware, manual and a syringe of thermal compound.

Zalman CNPS10X FlexFigure 2: Box contents.

In Figure 3 we can see the cooler. An amazing detail is that it supports one or two fans. Also, if your CPU hasn’t a high TDP and you have a well-ventilated case, you can use this cooler without adding any fan on it.

Zalman CNPS10X FlexFigure 3: CNPS10X Flex.

In the next pages we will see the cooler in details.

[nextpage title=”Zalman CNPS10X Flex”]

In Figure 4 we have a front view of CNPS10X Flex. The design is similar to CNPS10X Extreme, but with the heatpipes and fins showing their natural colors, except for the middle find, which are painted in black.

Zalman CNPS10X FlexFigure 4: Front view.

In Figure 5 we can see the rear of the cooler. You can install one or two fans (one at each side of the heatsink, improving the airflow).

Zalman CNPS10X FlexFigure 5: Rear view.

In Figure 6 we have a side view, where you can notice the five heatpipes.

Zalman CNPS10X FlexFigure 6: Side view.

[nextpage title=”Zalman CNPS10X Flex (Cont’d)”]

In Figure 7 we can see the cooler top, with a black plastic cap, giving it a very nice looks.

Zalman CNPS10X FlexFigure 7: Top view.
In Figure 8 we see the base of the cooler. Finishing is so good that the surface reflects like a mirror.
Zalman CNPS10X FlexFigure 8: Base.
As CNPS10X Flex does not come with a fan, we had to pick one for our benchmarking. We chose SilverStone FM123, the same we used on our SilverStone NT06-E and Prolimatech Megahalems Rev. B reviews. But note that the performance of this cooler will depend on the fan you pick.
Zalman CNPS10X FlexFigure 9: Fan installed.

[nextpage title=”Installation”]

CNPS10X Flex is compatible, according to the manufacturer’s webpage, with socket LGA775, 1156, AM3, AM2+, AM2, 939 and 754 CPUs, but our sample didn’t come with the clip for use it with sockets 939 and 754. But, frankly speaking, no one will buy a cooler like this to install on such obsolete CPU.

The clips that come with the cooler are simple and follow the same design. There is a pair of clips for Intel CPUs and another for AMD processors. In Figure 10 we can see the cooler with the Intel clips attached the base.

Zalman CNPS10X FlexFigure 10: Intel CPUs clips installed.

In Figure 11 we see the metallic backplate, which makes installation more stable and avoids the motherboard from bending due to the applied pressure. There is only one backplate used for all sockets, and all you have to do is to put the nuts in the correct place. An excellent system with plastic holders keeps the nuts in place during installation. So, the installation is very simple, even though you have to remove the motherboard from the case (unless it offers access to the solder side of the motherboard).

Zalman CNPS10X FlexFigure 11: Backplate.

In Figure 12 we can see CNPS10X Flex installed on our motherboard, still without the fan. Note the thin black strips on the heatsink: they are strips of self-adhesive rubber that helps  absorbing noise and vibration from the fan.

Zalman CNPS10X FlexFigure 12: Installed on our motherboard.

In Figure 13, you can see the cooler installed inside our case, with the fan in place.

Zalman CNPS10X FlexFigure 13: Installed in our case.

[nextpage title=”How We Tested”]

We are adopting the following methodology for our CPU cooler reviews.

First, we chose the CPU with the highest TDP (Thermal Design Power) we had available, a Core 2 Extreme QX6850, which has a 130 W TDP. The choice for a CPU with a high TDP is obvious. To measure the efficiency of the tested cooler, we need a processor that gets very hot. This CPU works by default at 3.0 GHz, but we overclocked it to 3.33 GHz, in order to heat it as much as possible.

We took noise and temperature measurements with the CPU idle and under full load. In order to achieve 100% CPU load on the four processing cores we ran Prime95 with the "In-place Large FFTs" option, and three instances of the StressCPU program, all at the same time.

We also compared the reviewed cooler to the Intel stock cooler (with copper base), which comes with the processor we used, and also with some other coolers we have tested using the same methodology.

Temperature measurements were taken with a digital thermometer, with the sensor touching the base of the cooler, and also with the core temperature reading (given by the CPU thermal sensor) from the from the SpeedFan program, using an arithmetic average of the four core temperature readings.

The sound pressure level (SPL) was measured with a digital noise meter, with its sensor placed 4" (10 cm) from the fan. We turned off the video board cooler so it wouldn’t interfere with the results, but this measurement is only for comparative purposes, because a precise SPL measurement needs to be made inside an acoustically insulated room with no other noise sources, which is not the case here.

Hardware Configuration

  • Processor: Core 2 Extreme QX6850
  • Motherboard: Gigabyte EP45-UD3L
  • Memory: 4 GB G.Skill F2-6400CL5S-2GBNY (DDR2-800/PC2-6400 with 5-5-5-15 timings), configured at 800 MHz
  • Hard drive: 1 TB Seagate Barracuda 7200.12 (ST31000528AS, SATA-300, 7200 rpm, 32 MB buffer)
  • Video card: PNY Verto Geforce 9600 GT
  • Video resolution: 1680×1050
  • Video monitor: Samsung Syncmaster 2232BW Plus
  • Power supply required: Seventeam ST-550P-AM
  • Case: 3RSystem K100

Software Configuration

  • Windows 7 Home Premium 64 bit

Software Used

Error Margin

We adopted a 2 °C error margin, i.e., temperature differences below 2 °C are considered irrelevant.

[nextpage title=”Our Tests”]

On the tables below you can see our results. We ran the same tests with the coolers shown on below tables. Each test ran with the CPU idle and the with the CPU fully loaded. On BigTyp 14Pro, TMG IA1, NH-U12P and ISGC-300 the tests were done with the fan at full speed and at minimum speed. The other coolers were connected directly to the motherboard and it controls the fan speed based on CPU load level and temperature on PWM models. ISGC-400, iCEAGE Prima Boss, Megahalems Rev. B, Thermaltake SpinQ VT and Zalman CNPS10X Flex were tested at minimum speed on idle test and at maximum speed on full load test.

CPU Idle

Cooler Room Temp. Noise Fan Speed Base Temp. Core Temp.
Intel stock 14 °C 44 dBA 1000 rpm 31 °C 42 °C
BigTyp 14Pro (min) 17 °C 47 dBA 880 rpm 29 °C 36 °C
BigTyp 14Pro (max) 17 °C 59 dBA 1500 rpm 26 °C 34 °C
Akasa Nero 18 °C 41 dBA 500 rpm 26 °C 35 °C
Cooler Master V10 14 °C 44 dBA 1200 rpm 21 °C 26 °C
TMG IA1 (max) 16 °C 47 dBA 1500 rpm 22 °C 30 °C
TMG IA1 (min) 16 °C 57 dBA 2250 rpm 21 °C 30 °C
Zalman CNPS10X Extreme 16 °C 44 dBA 1200 rpm 21 °C 29 °C
Thermaltake ISGC-100 18 °C 44 dBA 1450 rpm 35 °C 49 °C
Noctua NH-U12P (low) 15 °C 42 dBA 1000 rpm 20 °C 30 °C
Noctua NH-U12P 15 °C 46 dBA 1400 rpm 20 °C 28 °C
Noctua NH-C12P 17 &
deg;C
46 dBA 1400 rpm 23 °C 28 °C
Thermaltake ISGC-200 21 °C 43 dBA 1100 rpm 31 °C 35 °C
Schythe Kabuto 22 °C 42 dBA 800 rpm 29 °C 34 °C
Arctic Cooling Alpine 11 Pro 20 °C 43 dBA 1500 rpm 32 °C 39 °C
ISGC-300 (min) 18 °C 42 dBA 800 rpm 26 °C 30 °C
ISGC-300 (max) 18 °C 46 dBA 1400 rpm 24 °C 26 °C
SilverStone NT06-E 21 °C 66 dBA 2600 rpm 30 °C 41 °C
Zalman CNPS9700 NT 22 °C 48 dBA 1700 rpm 28 °C 35 °C
Scythe Mugen-2 17 °C 41 dBA 700 rpm 25 °C 30 °C
ISGC-400 (min) 17 °C 44 dBA 850 rpm 24 °C 30 °C
Cooler Master Vortex 752 20 °C 48 dBA 1700 rpm 32 °C 44 °C
iCEAGE Prima Boss (min) 22 °C 42 dBA 1000 rpm 29 °C 36 °C
Evercool Buffalo 17 °C 51 dBA 1850 rpm 22 °C 29 °C
Scythe Big Shuriken 20 °C 42 dBA 900 rpm 31 °C 39 °C
Cooler Master Hyper TX3 21 °C 44 dBA 1700 rpm 30 °C 39 °C
Titan Skalli 20 °C 43 dBA 1200 rpm 27 °C 34 °C
Prolimatech Megahalems Rev. B 21 °C 40 dBA 800 rpm 28 °C 32 °C
Zalman CNPS9900 NT 23 °C 45 dBA 900 rpm 30 °C 34 °C
Cooler Master Hyper N620 21 °C 44 dBA 1200 rpm 28 °C 34 °C
Nexus LOW-7000 R2 23 °C 46 dBA 1400 rpm 33 °C 42 °C
Evercool HPK-10025EA 20 °C 54 dBA 1900 rpm 27 °C 34 °C
Evercool HPH-9525EA 23 °C 50 dBA 1900 rpm 38 °C 49 °C
iCEAGE Prima Boss II 23 °C 42 dBA 1000 rpm 29 °C 35 °C
Thermaltake SpinQ VT 24 °C 45 dBA 950 rpm 32 °C 39 °C
Titan Fenrir 21 °C 42 dBA 950 rpm 29 °C 35 °C
Zalman CNPS 10 Flex 23 °C 40 dBA 800 rpm 32 °C 39 °C

CPU Fully Loaded

Cooler Room Temp. Noise Fan Speed Base Temp. Core Temp.
Intel stock 14 °C 48 dBA 1740 rpm 42 °C 100 °C
BigTyp 14Pro (min) 17 °C 47 dBA 880 rpm 43 °C 77 °C
BigTyp 14Pro (max) 17 °C 59 dBA 1500 rpm 35 °C 70 °C
Akasa Nero 18 °C 48 dBA 1500 rpm 34 °C 68 °C
Cooler Master V10 14 °C 54 dBA 1900 rpm 24 °C 52 °C
TMG IA1 (max) 16 °C 47 dBA 1500 rpm 27 °C 63 °C
TMG IA1 (min) 16 °C 57 dBA 2250 rpm 25 °C 60 °C
Zalman CNPS10X Extreme 16 °C 51 dBA 1900 rpm 24 °C 50 °C
Thermaltake ISG-100 18 °C 50 dBA 1800 rpm 58 °C 93 °C
Noctua NH-U12P (low) 15 °C 42 dBA 1000 rpm 28 °C 59 °C
Noctua NH-U12P 15 °C 46 dBA 1400 rpm 25 °C 54 °C
Noctua NH-C12P 17 °C 46 dBA 1400 rpm 37 °C 76 °C
Thermaltake ISGC-200 21 °C 48 dBA 1900 rpm 42 °C 68 °C
Scythe Kabuto 22 °C 47 dBA 1200 rpm 38 °C 63 °C
Arctic Cooling Alpine 11 Pro 20 °C 51 dBA 2300 rpm 49 °C 85 °C
ISGC-300 (min) 18 °C 42 dBA 800 rpm 36 °C 64 °C
ISGC-300 (max) 18 °C 46 dBA 1400 rpm 31 °C 56 °C
SilverStone NT06-E 21 °C 66 dBA 2600 rpm 39 °C 96 °C
Zalman CNPS9700 NT 22 °C 56 dBA 2600 rpm 34 °C 63 °C
Scythe Mugen-2 17 °C 46 dBA 1300 rpm 28 °C 54 °C
ISGC-400 (max) 17 °C 47 dBA 1400 rpm 36 °C 69 °C
Cooler Master Vortex 752 20 °C 55 dBA 2300 rpm 48 °C 92 °C
iCEAGE Prima Boss (max) 22 °C 53 dBA 2000 rpm 35 °C 59 °C
Evercool Buffalo 17 °C 51 dBA 1850 rpm 32 °C 67 °C
Scythe Big Shuriken 20 °C 50 dBA 1500 rpm 51 °C 85 °C
Cooler Master Hyper TX3 21 °C 53 dBA 2700 rpm 39 °C 66 °C
Titan Skalli 20 °C 47 dBA 1550 rpm 37 °C 69 °C
Prolimatech Megahalems Rev. B 21 °C 61 dBA 2600 rpm 30 °C 51 °C
Zalman CNPS9900 NT 23 °C 56 dBA 2000 rpm 34 °C 54 °C
Cooler Master Hyper N620 21 °C 50 dBA 1650 rpm 32 °C 56 °C
Nexus LOW-7000 R2 23 °C 53 dBA 1900 rpm 45 °C 74 °C
Evercool HPK-10025EA 20 °C 54 dBA 1900 rpm 39 °C 69 °C
Evercool HPH-9525EA 23 °C 50 dBA 1900 rpm 58 °C 100 °C
iCEAGE Prima Boss II 23 °C 56 dBA 2100 rpm 32 °C 56 °C
Thermaltake SpinQ VT 24 °C 52 dBA 1500 rpm 40 °C 68 °C
Titan Fenrir 21 °C 50 dBA 1600 rpm 33 °C 58 °C
Zalman CNPS 10 Flex 23 °C 61 dBA 2600 rpm 33 °C 59 °C

The next graph shows how many degrees Celsius the CPU core was hotter than room temperature during our idle tests.

 Zalman CNPS10X Flex

The next graph gives you an idea on how many degrees Celsius the CPU core was hotter than room temperature during our full load tests.

 Zalman CNPS10X Flex

[nextpage title=”Main Specifications”]

Zalman CNPS10X Flex main features are:

  • Application: Socket LGA775, 1156, 1366, AM3, AM2+ and AM2 processors.
  • Fins: Aluminum.
  • Base: Copper.
  • Heat-pipes: Five U-shaped copper heat-pipes.
  • Fan: One or two, 120 mm (not included).
  • Nominal fan speed: N/A.
  • Fan air flow: N/A.
  • Maximum power consumption: N/A.
  • Nominal noise level: N/A.
  • Weight: 1.5 lbs (700 g).
  • More information: https://www.zalman.com
  • Average price in the US*: USD 52.00

* Researched at newegg.com on the day we published this review.

[nextpage title=”Conclusions”]

When we tested CNPS10X Extreme a few months ago we were very impressed by its rock-solid aspect and by its performance. Today testing its "little brother" we also liked the results. Although CNPS10X Flex is not as beautiful as its most expensive brother – at least in our opinion, but taste is a very personal matter -, it performed practically the same as the other model.

You must keep in mind, however, that even being less expensive than CNPS10X Extreme, you still need to buy a good fan (or even two) in order to use it. At the end, it is not an inexpensive solution.

How the cooler will look inside your case will depend on the fan you pick, from a classic black one to a multicolor LED fan. So, this product has a reason for the "Flex" on its name, fitting the taste of the user.

Being a nice-looking cooler, with an easy and dependable holding system, versatile and with an excellent performance, Zalman CNPS10X Flex deserves the Hardware Secrets Silver Award.