ASRock X79 Extreme4 Review
So without the heatsinks we can more clearly see how the VRM and the PCH area are designed.
ASRock is using 6 phases for the CPU Cores(vCore) and 2 for the CPU VCCSA(System Agent), now you are wondering how does ASRock get all that power to the power hungry SBe CPUs with only 6 phases, and the answer would be that you don't need 8 or 12 or 16 phases to run a SBe CPU to 5 GHz and beyond. The truth is you just need a certain amount of power, and you can easily provide 30-40A of power per each phase if you use good parts or ones that have high current ratings. In the case of this board they are using very nice inductors, about 35-40A per phase. If you are wondering why the number of MOSFETs isn't just 2 per phase it is because only the 2 phases for the VCCSA use two MOSFETs per phase. ASRock decided to use 3 MOSFETs per phase, one high-side MOSFET is ONSemi 4927N which are rated for about 38A per phase at 25C, and two low-side MOSFETs are about 40A per phase at 25C. Normal operation of course isn't at 25C, more like 50C+ so make sure that you have a fan blowing over the VRM area when you are OCing. The VRM parts are selected to support overclocking.
So above is a CHiL CHL8328 a digital 8 phase controller with VRD12 certification. It is important to note that the ASRock X79 boards will be the last boards of ASRock to use CHiL or IR digital controllers, instead for Z77 ASRock has switched to using the analog controllers such as those from Intersil and STMicro devices. This controller is only found on ASUS boards because it is a part only sold to ASUS, however ASRock was able to use it because they buy in bulk with ASUS. The switch from digital to analog shouldn't be one that is widely observed because ASRock never implemented all the benefits of digital power control such as those settings you find in ASUS UEFI which allow you to control different parameters of the VRM. ASRock has only ever implemented LLC and some current limits, not all the OVP, OTP, transient controls, and temperature and power balance controls which are available with CHiL and IR digital power controllers. This could be because they don't use CHiL drivers, instead they use drivers from STMicro for their VRM, which could limit the amount of digital controls which can be implemented. You can see those drivers used below, and the same drivers were used on the Z68 Extreme7 Gen3 we looked at a while back.
Eight ST6743 drivers are used and are mounted on the backside. If you are wondering, yes drivers get hot beucase they switch on and off thousands of times per second, but the copper in the PCB should cool them down.
DRAM uses a single phase along with a Richtek single phase PWM with integrated driver. Each set of 2 DIMMs uses one phase each.
We are happy to see that ASRock is using the ALC898 which is a high quality 108dB SNR chipset which most high-end X79 boards are using. However we would have liked to see some more capacitors, but we will check audio performance later in the review. The nuvoTon NCT6776F provides SIO capabilities as well as the PS/2 ports on the back. A VIA VT6315N provides two IEEE 1394A ports. A Broadcom BCM57781 provides GBit LAN capabilities. Two ASMedia ASM1061 provide 4 extra SATA6GB/s ports, and two ASM1042 provide a total of four USB 3.0 ports.