Asus Crosshair IV Extreme
The Crosshair IV Extreme's heatsink follows on from the previously reviewed Formula motherboard.
All major integrated components are cooled by this single heatsink module. A single heatpipe connects two cooling arrays; the Northbridge and VRMs are kept at bay by the chunkier unit, while the Southbridge and Lucid chip sit under a metal plate. Naturally the heatpipe spans the whole length of the cooler.
There is a little more to the heatsink however. Those with a keen eye will have noticed two wires coming out of the VRM + NB cooling side of the heatsink. "OH NO", you might have exclaimed. Sadly we can only confirm your fears in that it is indeed actively cooled. Nope, it's not passive - there's a little fan sitting above the Northbridge! Thankfully the second cable isn't for another fan, but rather to power the LED that pulsates underneath the Republic of Gamers logo. But seriously, whether it has one or two fans, it's still bad news.
Let me tell you readers a short story - if you know me and my boring tales, then kindly skip paragraph.
Back in 2004, when AMD's Athlon 64 range and nVidia's nForce 4 MCPs were the king of platforms, Asus' motherboards were well known for one thing - Noise.
I remember the first time I ever came across the Asus A8N SLI Deluxe motherboard. It was great. It would let you combine two GeForce 6800 Ultra's in SLI, overclock Athlon 64 3000's to the dizzy heights of 2.70GHz and onwards and even had SATA II. This was all brilliant, except for one thing. Asus saw fit to cool their nForce 4 SLI chipset with a basic aluminium cooler and then drop a 40mm fan on top that would spin in excess of 7000RPM. It didn't push an awful lot of air but seriously, you could hear it from another room! Asus finally put an end to this with the release of the A8N SLI Premium, which sported a passive heatpipe design. From here on, the saga of active motherboard coolers were over...until now.
Needless to say, we installed the Crosshair IV Extreme with high hopes that the fan would rarely switch itself on...Oh how wrong we were. By default, the fan spins at its maximum speed and believe me it can be heard over the loudest of Multi GPU configurations. The motor noise is high pitched and much like the dreaded A8N Ultra/SLI series coolers, it can be heard from adjacent rooms.
Having now spoken to Asus, we were made aware of the fact that the 40mm fan was a space saving measure that replaces the optional "bolt on" fan that previous ROG packages included. Apparently the fan is only of use under conditions of low case airflow, such as watercooled CPU/GPU.
Our opinion still stands however. A 40mm fan can only move so much air during a given rotation and so it comes to no surprise that it has to spin very quickly. We would guess that the fan pushes no more than 20CFM. Even if the board's components are under stress due to low airflow, there is only so much this fan can do to ease temperatures. The endgame is that anyone that is serious about overclocking would ensure that there is sufficient airflow inside their chassis or on their test bench in the first place. Even a set of low speed 120mm fans in the vicinity of the motherboard would suffice in our opinion.
There is simply no way of sugar coating this. Asus are right; the heatsink is capable of cooling the Crosshair IV Extreme passively under most, if not all scenarios. Simply unplug it and the board will operate normally and in silence. On the basis of this, we continue to wonder why the fan was necessary in the first place but dwelling on this is futile.
We're almost out of pictures but fear not, the review will stay interesting for a while longer.