Section 1 Subsystems -
Memory -
Memory performance is very important on a motherboard, especially when you have a CPU with multiple cores and threads. If you have slow memory your cores and threads can become starved for data to execute. To test memory performance we run both Sisoft’s SANDRA and AIDA64. These two combine to not only give us accurate numbers but to validate each other. For testing at stock speeds the memory is hard set to 1333MHz while overclocking testing is done at the highest stable speed for the voltage of 1.65v this is due to the different memory dividers for each CPU. As such, the memory speeds will vary greatly. This means that the overclocked numbers are a little misleading and while they can show a trend are really only included to show if a board has a problem with memory performance at high clockspeeds.
As with most boards these days the Crosshair IV is limited by the Internal Memory Controller on the CPU. In this case the AMD memory controller has some performance issues. Some of this is due to the way it handles memory and caching. The AMD based IMC takes a bigger hit from the high latency found in most DDR3. This has been an Achilles Heel for AMD ever since the AM2 CPU when they had to make the move to DDR2. There are ways to compensate for this to a degree though and AMD has been working on these to make up for the slower memory performance. 
Drive performance -
Drive performance is also one of the major subsystems that goes to make up the performance of a motherboard. For our testing we use Sandra and AIDA64 again. We only test with single drives for each type of controller present on the motherboard (unless it is a professional product where we will use RIAD 5 and/or 10). We have also begun using a Seagate PS-110 USB 3 external HDD for our USB 3.0 performance. As a side note, we include the overclocked numbers here to make sure (again) that you are not going to see a major drop in performance due to minor instabilities at high clock speeds.
On the other side of the coin though AMD’s native SATA 3.0 controller is pretty fast. We are seeing excellent performance from both SATA 2.0 SSDs and SATA 3.0 HDDs. We are looking forward to seeing what we can get this to do when we get our SATA 3.0 SSDs in hand.
Power -
Power efficiency is another of those misnomers that we get caught up in. We hear about idle states and power gates. But what does that mean to you and I? On the surface having power management that reduces idle power sounds great and can be a benefit to someone that leaves their system on for long periods of time (and inactive) but how a system handles power under load and the delta between the two states is often more important than the idle power usage numbers. We use only P3 Kill A Watt instruments for measuring power.
The Asus Crosshair IV Extreme is not a terribly power efficient motherboard. Of course that is not unexpected considering the CPU has a 140 Watt TDP (Max) and the other pieces that we have in the board. Still, it does draw a little more power than we expected from an Asus board. Considering the fact that this is an enthusiast board and meant to be pushed I am fairly certain that will not put anyone off from buying it though.
Cooling (Board Level) -
Board level cooling is an important factor in product performance and longevity. Components like the chipset, VRM modules and even capacitors need to be kept relatively cool to prevent failure. As these parts are made of silicon, they have a thermal breakdown threshold; or melting point. At that temperature the actual transistors built into chip will begin to deform and break down. Granted, the threshold is often very high, but you still need to make sure that components stay away from this level of heat for longer product life.
Despite the beefy cooling on the Crosshair IV Extreme it has a hard time keeping up with the heat that can be generated by this board. A large part of this heat is the HydrLogix chip that is up by the power regulation, but the board gets a little hotter than we would like to be honest.
Audio -
Audio is highly subjective. What we find pleasing may sound “off” to you. That is always going to the problem with testing audio; results will vary too widely depending on the tastes of the listener. However, there are ways of measuring the audio output with an objective ear. There is also the issue of audio causing performance issues in gaming and video playback. The reason this is a potential source of concern is that all onboard audio CODECs (Compression/Decompression) are CPU controlled. This means that while the audio chip controls the audio levels and effects of the audio the actual work is done on the CPU. Usually this will not be a problem with today’s powerful CPUs. Even the lower and consumer level products can handle high-end audio these days. But again there is the chance that a bad design or software will hinder your system and performance. On the other side the limits of board space, cost, etc will also prevent the level of audio quality you can get from an add-in board. We test all audio parts with three media types, Movie (DVD), MP3 Music, and Gaming. These are pushed to our Tec On model 55 Tube Amp to see if we can detect any signal issues in the reproduction.
Board level audio is getting better and at the level that the Crosshair IV Extreme is at it should have good audio. Fortunately for you Asus has put a good audio CODEC on the Crosshair IV Extreme. We ran movies, games and MP3 audio through it and found it to be more than acceptable. It is true than an audiophile would not find it great, but if you are that picky you will want to get an add-in board anyway.
Networking -
This one is something that is a requirement anymore. If you have a computer, the chances are good (like 99%) that you are also connected to high-speed internet. With this you need a good and solid LAN chip to make sure that your data flows properly out and back.
Asus has put Intel Network chips on almost all of their boards now. This has improved their networking performance quite a bit. The Crosshair IV Extreme also has one of these handy little Intel LAN controllers. Because of this we saw great performance and better than average sustained transfer speeds when moving large files across our network.
