Arctic Accelero Hybrid II-120 Liquid GPU Cooler

Table of Contents

Arctic’s Acclero Hybrid II-120 combines an AIO liquid cooler with a back side heatsink to produce a formidable yet quiet cooling solution for high-end graphics cards.

December 8, 2014 by Lawrence Lee

Arctic Accelero Hybrid II-120 GPU Cooler
Street Price

Cooling a modern high-end graphics card quietly is a difficult task due to
the massive amount of heat they put out. Their unenviable position directly
adjacent to the CPU makes it tougher yet. Liquid cooling is a natural fit for
this cause, transferring the heat generated by the GPU core directly to a location
where it can be quickly expelled from the case. This allows all the components
to run cooler, as the heat doesn’t linger inside the case as long.

This advantage was evident when we reviewed the NZXT
G10 GPU bracket
, which allows a variety of closed loop CPU coolers to
be adapted for use on a graphics card. Paired with a NZXT
(140 mm radiator) and slapped onto a factory-overclocked GTX
, the results were tremendous. The GPU core temperature ended up
well under 70°C at an impressive noise level of 17~18 dBA@1m. Both the CPU
and PCH ran considerably cooler as well, so the effects were system-wide. Can
the all-in-one unit Arctic Accelero Hybrid II-120 perform similarly?

Formerly known as Arctic Cooling, Arctic is a bit of a legend as one of the
first aftermarket heatsink manufacturers to take on graphics card cooling. A
decade ago they launched the VGA Silencer, a classic that was the GPU-equivalent
of the Zalman CNPS7000. They received similar acclaim for the Accelero S1, a
superb fanless model, and followed that up with the formidable Accelero Twin
Turbo and Accelero Xtreme series.

Main components.

The Hybrid II-120 is Arctic’s second foray into liquid GPU cooling. The original Hybrid is a combined air/liquid cooling solution with a small fan blowing over the VRM. This model moves away from that paradigm, shifting VRM cooling to the opposite side of the PCB by utilizing a large fanless aluminum heatsink which can also help cool the memory chips and other components as well. A support bracket, that latches on to the screw points of four expansion slots, helps keep the card from bending from all that weight. Meanwhile, the GPU core itself is cooled by a basic AIO cooler with a 120 mm fan.

Package contents.

Due to the nature of the heatsink, the accessories are unusual for a GPU cooler.
A large blue thermal pad precut into 50 pieces is used to transfer heat from
the various board components to the back side heatsink. A protective plastic
film ensures the heatsink doesn’t directly contact any circuitry, but you have
to manually cut holes in it so the pads can make contact. Also included is a
syringe of Arctic’s MX-4 thermal compound, all the necessary bolts, screws,
nuts, and washers, and a bit of documentation.

Arctic Accelero Hybrid II-120: Specifications
(from the product
web page
Max. Cooling Capacity 320 Watt
Radiator Dimensions 150 x 120 x 25 mm
Pump Dimensions 70 x 70 x 28 mm
Heatsink Dimensions 218 x 98 x 23 mm
Total Weight 793 g
Fan Speed 400 – 1,350 RPM (Controlled by PWM)
Fan Airflow 74 CFM / 125.7 m³/h
Fan Noise Level 0.3 Sone @ 1,350 RPM
Fan Power 0.25A/+12V DC
Compatibility – Nvidia* GTX 980, 970, Titan (Black),780 (Ti), 770, 760(Ti), 680, 670, 660 (Ti), 650 (Ti boost), 580, 570, 560 (Ti,SE), 550Ti, 480, 470, 465, 460(SE), GTS 450, 250, 240 (OEM)
Compatibility – AMD* R9 290(X), 280(X), 270(X),R7 265, HD 8870, 7870(XT,GHz), 7850, 6970, 6950, 6870, 6850, 6790, 5870, 5850, 5830, 4890, 4870, 4850, 4830, 3870, 3850, 3690
*Accelero Hybrid II-120 is compatible only with the graphics card using a standard size PCB with a width of 98mm. Graphics cards with different dimensions will not be compatible with this cooler. This includes:
-Low profile Graphics card
-Graphics cards with extended PCB (such as : ASUS DirectCU II R9 290, GTX780-DC2OC-3GD5)

The compatibility list is based on AMD Radeon and NVIDIA’s reference board layout only. ARCTIC holds no responsibility for incompatibility on non reference boards. Please check the height restriction drawing before purchase.

In the vast majority of the cases, it is not possible to assembly this cooler when the graphics card is located in the first extension slot of the motherboard.

The official specifications list quite a few video card models as compatible
but there are several caveats.

  • The card must have a standard size PCB (98 mm wide).
  • It can’t be a low profile model.
  • Arctic can’t guarantee it will work on non-reference boards.
  • The fan is controllable via PWM but connects directly to the graphics card
    with a 4-pin connector. Some video cards utilize 5-pin headers but they are
    out of luck as no adapter is included.


The Arctic Accelero Hybrid II-120’s main cooler has a 7.0 x 7.0 x 2.8 cm base, 41 cm of tubing, and a 14.9 x 12.0 x 2.7 cm radiator, according to my measurements. The aluminum heatsink for the back of the card weighs 340 grams on its own, with dimensions of 21.7 x 9.8 x 2.3 cm.

The cooler uses the familiar round base design found in most AIO models manufactured by Asetek. The pump inside is powered by a molex connector so its speed is not controllable unless the cable is modified or an adapter is used.

The copper plate at the bottom is not only convex but is essentially conical with a prominent apex at the center. Circular machine marks are also visible, some fine, some rough.

The radiator is modestly sized, only 2.7 cm thick, and uses the typical wafer thin coil design.

The heatsink is rather tall and is long enough to almost completely cover the PCB of most standard sized video cards. The fins are 1 mm thick on average with a gap of 4 mm between them.

The Hybrid II utilizes one of Arctic’s 1350 RPM F12 PWM fans with a slightly modification. It has a 4-pin PWM connector but it’s the smaller type that plugs directly in the video card rather than a motherboard fan header.


The most critical aspect of installation is firm, maximum contact
between the base and the GPU core for efficient heat conduction. Ideally
it should also be a simple procedure with the user having to handle as few pieces
of hardware as possible. The procedure for installing the main cooler itself satisfies these conditions but mounting the additional heatsink is more complex.

The first step is to apply thermal compound to the center of the copper
base, then secure the bolts to the mounting frame using the appropriate
holes for the video card in question. Plastic washers go over them to
prevent shorts, and depending on the GPU model, a set of washers may also
be required to ensure proper spacing.

Our ASUS GTX 680 test card with the stock cooler, backplate, and VRM heatsink
removed. Technically it’s not a compatible card because its PCB is wider
than the standard 98mm… but we have our ways.

A set of 50 small blue thermal pads are included to facilitate heat transfer between what Arctic calls the “hot areas” and the heatsink. They don’t specify exactly what these areas are or how to identify them, but basically it’s the memory chips, VRMs, and any other component that contacts the stock cooler. These chips are probably easier to cool from the backside as the card itself doesn’t get in the way of natural convection. A protective film, with holes cut out to accommodate these pads, is supposed to go down as well to electrically insulate the heatsink, but I found it was unnecessary in this case.

The card is lowered onto the base of the water cooler base and the bolts come through from the other side. Rectangular brackets are placed over them so the nuts have something against which to hold them.

To secure the heatsink, six clips are provided (three on each side) that attach to the ridges running along the length of the heatsink. However, this system is designed for a standard width card (9.8 cm), so the clips don’t reach on our 10.8 cm wide card. My solution to this is a series of cable ties daisy-chained together.

Not the most elegant solution but it is practical. Without the clips in place, the support bracket is also unusable so the card will bend to some degree due to the weight of the heatsink.

My favorite thing about water cooling a graphics card is not having to worry about board components getting in the way. The base is pleasantly compact.


After installing the graphics card, the last step is to mount the fan to the radiator and the radiator to the case. This is accomplished easily enough but with the nature of this cooler, there are some compatibility issues that need to be pointed out.

First off, a thoughtless annoyance. Instead of using long bolts like almost
every liquid cooler on the market, short screws are provided instead.
This requires a very thin screwdriver, one with a shaft narrow enough
to fit through fan mounting holes. The fan’s 4-pin header is also not
compatible with our card’s 5-pin connector. Luckily, I have a 3-pin adapter
from an old GELID Icy Vision handy which allows it to be powered by the
motherboard and be controlled.

The Hybrid II’s tubing is long enough to reach most of the fan positions in the Fractal R5 case but the top/front mount is ideal as it’s far away from the processor. The radiator gets very hot and its proximity to the socket can negatively affect both.

Without the support bracket, the weight of the heatsink forces the card downward. The right side of the card has a noticeble 10 mm droop.

The pads are thick enough that the heatsink doesn’t come close to touching any of the bits on the trace side of the PCB, though perhaps the stock clips would compress them further.

The heatsink is 23 mm tall and thermal pads add another 2 mm, so almost a full inch is added to the back of the card. There is about 5 mm of clearance between it and the CPU cooler, a Scythe Kotetsu. A wider tower heatsink could cause interference. The PCI-E 1x slot above the card is also rendered unusable.

The heatsink also overlaps the board’s USB 3.0 header. Ripped from its home, the bulky front USB 3.0 cable looks decidedly depressed.


Test Platform

  • Intel Core i3-2100 processor, Sandy Bridge core, dual
    core 3.1 GHz, integrated HD 2000 graphics, TDP of 65W.
  • Scythe Kotetsu CPU cooler – Scythe Slip Stream 500RPM 120mm
  • Gigabyte Z77X-UD3H motherboard, Z77 chipset, ATX.
  • Kingston HyperX Genesis memory, 2x4GB, DDR3-1600.
  • Kingston SSDNow mS100 mSATA solid state drive – 64GB
  • Kingwin Lazer Platinum power supply, ATX v2.2, 80 Plus Platinum,
    1000W total output, 83A on +12V rail.
  • Fractal Design Define R5 case – ATX, stock 140mm fans.
  • Microsoft Windows 7 Ultimate operating system, 64-bit

Measurement and Analysis Tools

Test Procedure

Our test procedure is an in-system test, designed to determine whether the cooler is adequate for use in a low-noise system.
By adequately cooled, we mean cooled well enough that no misbehavior
related to thermal overload is exhibited. Thermal misbehavior in a graphics
card can show up in a variety of ways, including:

  • Sudden system shutdown, reboot without warning, or loss of display signal
  • Jaggies and other visual artifacts on the screen.
  • Motion slowing and/or screen freezing.

Any of these misbehaviors are annoying at best and dangerous at worst —
dangerous to the health and lifespan of the graphics card, and sometimes to
the system OS.

Coolers are installed on an ASUS GeForce GTX 680 DirectCU II OC, a factory-overclocked single GPU card that draws 200W~205W by our estimates. The stock VRM heatsink is left on if possible. Noise is measured and recorded with our test system on with the cooler installed. Our mic is positioned at a distance of one meter from the center of the case’s left side panel at a 45 degree angle. The GPU temperature is recorded using GPU-Z.

Our main test consists of FurMark stability test running in conjunction with Prime95 to stress both the graphics card and processor simultaneously. This combination produces more CPU/GPU stress than a typical gaming session. As our test system has limited airflow, our results are not indicative of a real-world situation, but rather a worse-case scenario. If the cooling solution in question can cool the card and its components adequately in this environment it means there will be some degree of thermal headroom when deployed in a more conventional situation.

The cooler’s fan(s) is connected to the motherboard (if possible) and its speed is changed to various levels to represent a good cross-section of its airflow and noise performance. If it’s a passive heatsink, we use different predefined system fan speeds to determine the effect of system airflow on cooling performance.

GPU Test System:
Anechoic chamber measurements
Case Fan Setting
System SPL@1m
24 dBA
15 dBA
12~13 dBA
Note: mic is positioned at a distance of one meter from the center of the case’s left side panel at a 45 degree angle.


For heatsinks that support but don’t include standard case fans, our reference fans are used. The measured details
of these models are shown below, derived using our standard fan testing methodology.

Reference Noctua 140mm fan
Anechoic chamber measurements
28~29 dBA
1250 RPM
21 dBA
990 RPM
18 dBA
880 RPM
15~16 dBA
770 RPM
13 dBA
660 RPM


Reference Nexus 120mm fan
Anechoic chamber measurements
16 dBA
1080 RPM
13 dBA
880 RPM
12 dBA
720 RPM


Reference Nexus 92 mm fan
Anechoic chamber measurements
16 dBA
1470 RPM
12 dBA
1150 RPM


Specifications: Arctic Accelero Hybrid II-120 Stock Fan
Manufacturer Arctic Power Rating 3.0 W
Model Number F12 PWM Airflow Rating 74 CFM
Bearing Type Fluid Dynamic Speed Rating 400 ~ 1350 RPM
Frame Size 120 x 120 x 25 mm Noise Rating 0.3 Sone
Hub Size 35 mm Header Type 4-pin PWM VGA
Blade Diameter 113 mm Starting Voltage < 4.0 V
Cable Length 40 cm Weight 100 g
Corner Type Open Retail Availability Yes (w/ standard PWM header)

Additional notes:

The included 120 mm is nothing remarkable from a design perspective, aside for perhaps the small hub, measuring only 35 mm across. It has nine blades of modest size and curvature with sharp tips. It’s a 4-pin PWM model but the header is the smaller VGA type.

Noise Measurements
(GPU Test System w/Accelero Hybrid II-120)
Radiator Fan Speed
Total SPL@1m
1390 RPM
27~28 dBA
990 RPM
20 dBA
850 RPM
17 dBA
560 RPM
15 dBA
Pump Only
14 dBA
Measuring mic positioned 1m at diagonal angle from
the center of the heatsink. System fans on low speed, CPU fan at 500 RPM.
System noise level without GPU: 12~13 dBA. Ambient noise level: 10~11

Our GPU test system is very quiet, producing just 12~13 dBA@1m when running on integrated graphics. The system fans are set to low speed (5V) via the case’s integrated fan controller and the CPU fan is limited to only 500 RPM.

As with all liquid coolers, the pump produces some noise as well, but surprisingly,
not very much. With the card installed, the pump on, and the radiator fan disabled
momentarily, the overall noise level is only 14 dBA@1m — this is with the
pump receiving a full 12V.

27~28 dBA@1m is the loudest this machine gets with the radiator fan at full speed and it crosses the quiet threshold (~20 dBA@1m) once it gets down to about 1000 RPM. With a low starting voltage, it’s capable of speeds as low as 400 RPM but any level in-between would be more than acceptable from a noise perspective.

The pump generates a mild but distinct buzzing at all times and occasionally there’s an audible sloshing/gurgling of the liquid inside but overall, it sounds relatively pleasant, at least as far as pumps go. Some tonality is produced at ~160 and ~850 Hz but it’s not noticeable at distance.

Arctic has a good track record when it comes to stock fans and this one is no different. It has an exquisitely smooth and innocuous sound at speeds under 1000 RPM. Most of the small peaks produced in the spectrum above are from the pump.


Load Test Results: Arctic Accelero Hybrid II-120
Prime95 + FurMark
Radiator Fan Speed
560 RPM
560 RPM
850 RPM
990 RPM
1390 RPM
CPU Temp
PCH Temp
GPU Temp
System Power (AC)
15 dBA
15 dBA
17 dBA
20 dBA
27~28 dBA
System noise level without radiator fan (pump only): 14~15 dBA@1m.
System noise level without GPU: 12~13 dBA@1m.
Ambient temperature: 22°C

The GTX 680 malfunctions when the GPU temperature reaches 88°C but the
Hybrid II stays comfortably away from this mark. Even with the fan spinning
at a paltry 560 RPM, the GPU core stays below 80°C, and a modest increase
in fan speed brings it down by double-digits. The performance is hugely dependant
on the speed of the radiator fan, though the rate of improvement slows beyond
about 1000 RPM.

The back heatsink does a fairly good job as well, keeping the VRMs adequately
cooled at or below 100°C (they can take a lot more than that). The VRM,
CPU, and PCH temperatures all run cooler as the radiator fan speed is ramped
up. It’s clear that pulling the heat away with water cooling is beneficial to
all the components, not just the GPU.


Comparison: CPU + GPU Load
(Pump/VRM Fan Speed)
GPU/Rad. Fan Speed
GPU Temp
CPU Temp
Stock Cooling
1100 RPM
17 dBA
Arctic Accelero Hybrid II-120
850 RPM
17 dBA
560 RPM
15 dBA
NZXT X41 + G10 (1820/1000 RPM)
770 RPM
18 dBA
680 RPM
17 dBA
System noise level without GPU: 12~13 dBA@1m.
Ambient temperature: 22°C

The Hybrid II absolutely crushes the stock cooler at the 17 dBA@1m level. Not
only does the GPU core run much cooler, the VRM temperature improves by almost
20°C, an impressive feat considering it uses a fanless heatsink. The CPU
receives 8°C of relief as most of the heat normally rising from the
GPU is siphoned away to the radiator. The stock solution actually has an impressive
three-slot design with a rather thick heatsink, so it’s closer to an aftermarket
model rather than a typical OEM cooler.

Against the NZXT X41 + G10 combination, the results are very close. Despite
its smaller radiator and fan size, the Hybrid II holds a 6°C advantage when
both coolers are producing an overall system noise level of 17 dB@1m. The CPU
basically gets the same cooling benefit with either the Arctic or the NZXT,
while the latter has a slight edge in VRM cooling.


These recordings were made with a high
resolution, lab quality, digital recording system
inside SPCR’s
own 11 dBA ambient anechoic chamber
, then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recording starts with 5 second segments of room ambiance, then the machine idling with the case fans on low speed, then the cooler’s fan
at various levels. For the most realistic results, set the volume so that
the starting ambient level is just barely audible, then don’t change the volume
setting again.

  • Arctic Accelero Hybrid II-120
    — stock fan off, pump only (14 dBA@1m)
    — stock fan at 560 RPM (15 dBA@1m)
    — stock fan at 850 RPM (17 dBA@1m)
    — stock fan at 990 RPM (20 dBA@1m)
    — stock fan at 1390 RPM (27~28 dBA@1m


I expected the Arctic Accelero Hybrid II-120 to perform well but am surprised it manages to compete so strongly with the larger NZXT G41 + G10 combination. It actually delivers slightly better GPU cooling while maintaining an excellent level and quality of noise. The pump is not controllable but even at full speed, it’s one of the least offensive sounding models I’ve encountered, and the included fan has silky smooth acoustics. Arctic’s passive trace-side heatsink approach is not as effective as the G10’s 80 mm fan but it’s more than competent, only trailing the NZXT solution by a few degrees in VRM temperature. It takes some work to assemble, but the design, utilizing thermal pads to contact areas that need additional cooling, allows it to support a wide variety of different board designs.

However, failing to provide proper compatibility for wider PCBs rules out many
variants of non-reference, high-end graphics cards (of the Radeon R9 290X and
the GeForce GTX 780 and 980, for example) — the kinds of cards that can
benefit most from the Hybrid II’s capabilities. It’s technically incompatible
with these models as the clips can’t clamp onto the heatsink, but it can be
jerry-rigged to work for the most part. The heatsink intrudes a good inch into
the space normally reserved for the CPU cooler, and this could cause headaches.
It can also block portions of the motherboard: It covers the expansion slot
above, and on our platform, it interferes with the internal USB 3.0 header.
The fan uses a 4-pin video card connector, which is great as it won’t take up
an extra 3-pin fan header, but if your video card has a 5-pin design, you’re
out of luck as an adapter isn’t included.

If these various compatibility issues don’t apply or are acceptable, the Accelero
Hybrid II-120 is certainly a solid candidate, a formidable yet quiet cooler
worthy of any high-end graphics card. It’s currently selling for around $100,
a fair bit to add to the already high cost of a high-end graphics card, but
it delivers top-notch performance and improves cooling system-wide. It also
offers a bit better value than the NZXT X41 and G10 bracket combination.

Our thanks to Arctic for the Accelero Hybrid II-120 graphics card cooler sample.

* * *

Arctic Accelero Hybrid II-120
is Recommended by SPCR

Articles of Related Interest
NZXT Kraken G10 Graphics Adapter

Prolimatech MK-26 Multi-VGA Cooler

SPCR’s 2012 Graphics Card/Cooler Test System

ASUS GeForce GTX 680 DirectCU II OC

Thermalright Shaman 140mm Fan GPU Cooler

Arctic Cooling Accelero Xtreme Plus GPU Cooler

* * *

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