DirectCU II cooler: performance and noise level
Besides the enhanced power system and
pre-overclocked GPU, ASUS GeForce GTX 660 DirectCU II OC features the special
cooler DirectCU II.
DirectCU
II cooler
It consists of heat-sink aluminum and 3
copper 8mm-thick heat pipes covered with nickel.
The radiator’s base stands out with
direct-touch tech with 1.5-mm gap between heat pipes.
Despite that, its finish quality isn’t
perfect. The central pipe is the only one to be used 100% whereas the other two
get most of the heat through the aluminum coat that fills the gaps between the
pipes.
The entire system is cooled off with 2 75-mm
fans fixed safely in a metal frame.
Firstd FD7010H12S fan blades are compatible
with speed for setting PWM platform.
FirstD
FD7010H12S fan-blade suite
The speed changes automatically in a range from
1000 to 3500 RPM. The highest power consumption of each fan is not higher than
4.2 watts. The fans seem to run on pretty loose axis.
To test the cooler’s efficiency we perform
five consecutive tests with Aliens vs. Predator (2010) game with the highest
image quality settings in 2560x1440 resolution and 16x anisotropic filtering
and anti-aliasing in graphics images are 4x. We use MSI Afterburner 2.3.1 and
GPU-Z 0.6.7 as controlling tools. This test was performed in a closed system with
24°C room temperature. All thermal tests are carried out before we took the
card apart, which means that with its default thermal platform still remain
unchanged.
And here are the temperature data of Asus
GeForce GTX 660 DirectCU II OC:
Automatic
fan mode and Max fan mode
At regular automatic fan mode, GPU only has
max temperature at 62°C, the fans rotating at 1590 RPM only. At the maximum
speed of 3540 RPM the GPU temperature is 53°C. Advanced power system-DirectCU
II proved its highest efficiency but we wanted more. So, we perform and
additional test at 25% fan speed, which was equivalent to 1170 RPM. The
DirectCU II, one more time, did a well job, keeping the GPU always cool at
68°C.
When
running 25% fan speed
This performance is impressive but does
DirectCU II operate quietly? We measured its noise level by our traditional
method.
We measured the level of noise using a
noise-level meter CENTER-321 in a closed and quiet room about 20m2
wide meters large. The noise-measuring process was done outside the system
case, when the only noise source was the cooling system and its fans. The noise-level
meter was fixed up on a tripod at a distance of 15 centimeters from the fan
rotor. The mainboard with the graphics card was placed right at the edge of a
desk on sheet with polyurethane foam. The lowest noise reading that our
noise-level metering device measured is 29.8 dBA and subjectively the noise
level in testing condition from this distance is 36 dBA (not low, acceptable).
The rotating speed of the graphics cards’ fans was changed with the help of a
special controller collative with 0.5 V voltage adjustment increments.
Here’s the graph (the vertical dotted lines
represent the top speed of the fans in the automatic regulation mode).
Graphs
illustrating noise level
ASUS DirectCU II obviously works quieter
than the other two graphics cards with original coolers. The difference is very
valuable. Moreover, DirectCU II doesn’t lose the useful readings in the
automatic mode. In other words, we can’t hear any sound from a quiet computer.
This is in fact one of the quietest graphics cards we’ve ever tested.
Overclocking ability
First, we tried to overclock our ASUS
GeForce GTX 660 DirectCU II OC at default GPU voltage and found that it have
good overclocking ability in terms of GPU frequency and average level in terms
of memory frequency. Without ensuring about stability and image quality we tried
increasing GPU and memory clock rates by 140 and 780 MHz, respectively.
Check
the overclocking ability
Measured clock rate is 1160/1225/6788 MHz:
Result
table of clock rate
It’s a good result, especially as the GPU’s
clock rate is increased to 1255 MHz when opening at max with temperature no
higher than 62oC.
Illustrating
with graph
The top speed of DirectCU II fan is only 30
RPM higher than the default clock rate, at 1620 RPM.
Power-consuming process
We measured the power consumption of our
test equipped with different graphics cards using a multifunctional Zalman
ZM-MFC3 panel, which can report in detailed how much power a computer (without
the monitor) consume. There were two test modes: 2D (editing documents in
Microsoft Word or web surfing) and 3D (three times running the Metro 2033: The
Last Refuge with standard at 2560x1440 when set at maximum image quality
settings, but without antialiasing).
For comparison purposes, we also added the
results for ASUS GeForce GTX 660 Ti DirectCU II TOP 2 GB, Sapphire Radeon HD
7870 GHz Edition OC 2 GB and HIS 7850 IceQ Turbo X 2 GB to the distribution
table. Let’ see what’s the result:
Power-consuming
result
Configurations with different graphics
cards don’t affect their power consumption much. The system with Sapphire
Radeon HD 7870 OC consumes more than the others, up to 408 watts when opening
at peak level, which is 30 watts higher than required power level by ASUS
GeForce GTX 660 Ti TOP. The overclocked ASUS GeForce GTX 660 consumes 10 watts
more but has the same power consumption as the 660 Ti TOP at the default clock
rates. The HIS Radeon HD 7850 IceQ Turbo X system is the most power-saving one.
We can only add 500-watt PSU and it is
going to be enough for any of aforementioned configurations. Each of them needs
no more than 220 watts in 2D mode.
