It used to be that we would post a nice big picture of the top of the motherboard, and map out all the various VRM components – which phases are powered by which PWM, etc. For example, check out page 2 of our Gigabyte Z77X-UD5H review.
However with Haswell, the job became very simple: provide the CPU’s integrated VRM with a good supply of voltage, and it will do most of the heavy work, taking care of ripple itself. The motherboard’s VRM is relegated to converting the 12v input from the PSU to the correct CPU input voltage. So now, we can cover the entire CPU VRM with a simple picture with no graphics added.
Actually this is an incredibly powerful VRM to be used with Haswell, all things considered. Let’s take a closer look at what makes this 16 phase VRM special.
First of all, everything is handled by International Rectifier’s fully digital IR3563B PWM. It was designed specifically for Haswell, which is why it is a straight up single loop PWM with 8 phases. There is no longer a need for “6+2” types of PWMs with Intel VR12.5 specs.
So how do you get 16 phases to the CPU while using an 8 phase PWM? You use doublers:
The Z87X-UD4H uses IR3599 phase doublers (they can also be used as quadruplers by the way) to take each phase and split it into two more. Each of these phases is handled by an IR3553M “PowIRstage” Driver MOSFETs – this is the kind that includes a driver and MOSFET in one package. Each of these is good for 40A, although only 8 can be “on” at any given time.
Essentially, this is the only difference between the Z87X-UD4H and UD3H besides heatsink color. This one has doublers and 16 MOSFETs, and the UD3H just has 8 MOSFETs.
As for whether you need 16 powerful MOSFETs for Haswell… The biggest advantage by going with 16 phases is likely to be lower heat, as the load is spread across more phases that don’t have to work as hard.
Finally, everything goes through some ferrite chokes, then through some custom black Nippon Chemi Con 10K hour capacitors rated for 5600 uF capacitance.
The RAM VRM continues the trend of being slightly overkill on the Z87X-UD4H. It is also fully digital, controlled by an IR3570A 3+2 phase PWM. In this case, it’s being used in “1+1” mode, with the two phases sent to an IR3598 dual phase driver. From there, the phases go through a pair of Renesas K0393 MOSFETs, then the chokes and caps. This is absolutely more than you’ll ever need from a RAM VRM, and that’s a good thing.
Z87X-UD4H Component Tour
Now to cover every important component on the motherboard. This time we’ll start with an interesting array of features intended to be used on an open bench:
The Z87X-UD4H has a few useful features for open bench use. The big power button is always a welcome feature, as is a reset button and clear CMOS button. I appreciate that the buttons are different colors, but I would prefer for them to feel different as well. It’s almost too easy to clear your CMOS when all you want to do is hit reset…
The switches at the top are for the dual BIOS feature, which Gigabyte have revamped for their 8-series boards. One of them switches between the two BIOS chips like before, but the other switches the board between having two completely separate BIOSes that can be manually flashed, or the old method of just having one as a backup for the main one.
If you were wondering why one of the internal USB 3.0 headers on the Z87X-UD4H is red while the other is black, that has to do with showing which version supports Gigabyte’s high amp output (even while the power is off) feature they call “On/Off Charge”. This is achieved by adding a pair of Texas Instruments TPS2546 charge controllers that were designed exactly for this purpose. We’ll see how the software works later in the review.
This header is also the only one that connects directly to the Intel PCH. The other two USB 3.0 lanes each go to these:
These are Renesas D720210 USB 3.0 hubs, each of which takes one USB 3.0 port and splits it into four. We’ll compare the performance against the native USB 3.0 connections, although we haven’t seen a problem with these hubs before.
As usual, Gigabyte turns to iTE for SuperIO purposes. The IT8728F on the left handles the hardware monitoring and fan control features as well as supplying a PS/2 port, while the IT8892E on the right is used as a PCI-E > PCI bridge.
The Marvell 9172 handles the extra SATA connectivity that is offered on the Z87X-UD4H. It only controls 2 ports though, so the 2 internal headers are shared with the 2 eSATA headers. This means that only one or the other can be used at the same time. Since the Z87 chipset finally has full SATA 3.0 connectivity, this shouldn’t be an issue.
The Z87X-UD4H only has one Ethernet port, but it’s a good one. The Intel WGI217V PHY should allow full use of the Ethernet MAC that is on the Z87 PCH, without adding much in the way of CPU usage. We’ll test this later in the review.
Even though Gigabyte don’t seem to make a big deal of it in their promotional materials, their audio solutionon the Z87X-UD4H is actually quite good for integrated audio. They use a Realtek ALC898, which has full 110 dB SNR on all output channels, and keep the sound clean with the caps you see to the right. To the left is a Texas Instruments DRV632 line driver for the front headphone port. We’ll test the output each of these individually.
That about does it for our component tour. As you can see, Gigabyte use some pretty high quality parts, from VRM design that is more than capable, to Intel Ethernet, and more. Now to put all this to the test…