ASUS H81M-A Motherboard – Hardware Secrets

[nextpage title=”Introduction”]

Today, we are going to take a look at the ASUS H81M-A, a value socket LGA1150 motherboard based on the Intel H81 chipset. It has only two memory sockets, one PCI Express x16 slot, two USB 3.0 ports, and two SATA-600 ports. Let’s see whether it is a good pick.

The Intel H81 is still the most basic chipset for fourth-generation Core i CPUs from Intel. The main differences between this entry-level chip and the high-end model of its generation, the Z87, are the lower number of SATA-600 ports and USB 3.0 ports (two versus six of each), the absence of RAID and SRT (Smart Response Technology) support, and the support for only one PCI Express 3.0 x16 slot. There is no support (at least officially) for changing the clock multiplier on “K” unlocked CPUs, which makes it a bad choice for overclocking.

You can see the ASUS H81M-A motherboard in Figure 1. It uses the microATX form factor, measuring 8.9” x 6.9” (226 mm x 175 mm).

[nextpage title=”Slots”]

Unlike high-end chipsets, the H81 does not allow the bandwidth of the PCI Express 3.0 x16 slot to be shared with additional slots.

The ASUS H81M-A comes with one PCI Express 3.0 x16 slot and two PCI Express 2.0 x1 slots.

Of course, this motherboard does not support CrossFireX or SLI technologies.

Figure 2:

[nextpage title=”Memory Support”]

Intel socket LGA1150 CPUs have an embedded memory controller, meaning that it is the processor, not the chipset, that defines what memory technologies you can have and the maximum amount of memory that is possible. The motherboard, however, may have a limitation as to how much memory can be installed.

The integrated memory controller from socket LGA1150 processors supports DDR3 memories up to 1,600 MHz. According to ASUS, the H81M-A also supports memories up to 1,600 MHz.

The ASUS H81M-A has two memory sockets. You can have up to 16 GiB with this motherboard if you use two 8 GiB modules.

In order to enable the dual-channel mode, you must install two identical memory modules.

Figure 3: memory sockets; install two modules for the best performance

[nextpage title=”On Board Peripherals”]

The Intel H81 chipset is a single-chip solution, which is also known as a PCH (Platform Controller Hub). This chip has two SATA-600 ports and two SATA-300 ports, with no RAID support. The ASUS H81M-A offers all of them. Figure 4 shows the SATA ports.

Figure 4: SATA-600 (yellow) and SATA-300 (black) ports

The Intel H81 chipset supports ten USB 2.0 ports and two USB 3.0 ports. The ASUS H81M-A offers eight USB 2.0 ports, four located on the motherboard’s rear panel and four available through two headers located at the motherboard; and two USB 3.0 ports, available on the motherboard’s rear panel.

The motherboard does not support FireWire or Thunderbolt ports.

This motherboard supports 7.1 audio format using a Realtek ALC887 codec. This codec has the same specifications as the Realtek ALC892, except that the ALC892 has two extra channels for audio streaming. The main specifications for this codec include 97 dB signal-to-noise ratio for the analog outputs, 90 dB signal-to-noise ratio for the analog inputs, and up to 192 kHz sampling rate for both inputs and outputs, with 24-bit resolution. These specs are good for the mainstream user, but if you are looking into working professionally with audio editing, you should look for a motherboard that provides an SNR of at least 97 dB for the analog inputs.

The analog audio outputs are shared, which means if you want to install a 5.1 analog speaker set, you can not use the microphone and line-in inputs. There is no optical SPDIF output. There is a header labeled “SPDIF_OUT”, where you can install an adapter to have a coaxial SPDIF output or to connect a cable to older video cards that required a physical connection to have audio on their HDMI outputs.

The portrayed motherboard has one Gigabit Ethernet port controlled by a Realtek RTL8111G chip.

The product supports installation of a TPM (Trusted Platform Module), which stores encryption keys in order to improve the computer’s security.

In Figure 5, you can see the motherboard’s rear panel with PS/2 keyboard and mouse connectors, HDMI output, VGA output, DVI-D output, four USB 2.0 ports, two USB 3.0 ports, Gigabit Ethernet port, and the shared analog audio connectors.

Figure 5: motherboard rear panel

Figure 6 shows the simple set of accessories that comes with the motherboard.

Figure 6: accessories

[nextpage title=”Voltage Regulator”]

The voltage regulator of the ASUS H81M-A has three phases for the CPU. The voltage regulator is controlled by a Digi+ ASP1258A integrated circuit, using a digital design. Each phase is driven by two PH7730DL transistors, as shown in Figure 7.

Figure 7: voltage regulator circuit

The motherboard uses solid electrolytic capacitors and ferrite coils.

If you want to learn more about the voltage regulator circuit, please read our tutorial on the subject.

[nextpage title=”Overclocking Options”]

The ASUS H81M-A has a few overclocking options. Below, we list the most important ones (2001 BIOS):

• CPU Core Voltage: from 0.001 V to 1.920 V in 0.001 V increments
• CPU Core Voltage offset: from -0.999 V to +0.999 V in 0.001 V increments
• CPU Cache Voltage: from 0.001 V to 1.920 V in 0.001 V increments
• CPU Cache Voltage offset: from -0.999 V to +0.999 V in 0.001 V increments
• CPU Graphics Voltage: from 0.001 V to 1.920 V in 0.001 V increments
• CPU Graphics Voltage offset: from -0.999 V to +0.999 V in 0.001 V increments
• CPU System Agent Voltage offset: from -0.999 V to +0.999 V in 0.001 V increments
• CPU Analog I/O Voltage Offset: from -0.999 V to +0.999 V in 0.001 V increments
• CPU Digital I/O Voltage Offset: from -0.999 V to +0.999 V in 0.001 V increments
• SVID Voltage: from 0.001 V to 2.444 V in 0.001 V increments
• Memory Voltage: from 1.350 V to 1.650 V in 0.01 V increments
• CRTL REF Memory Voltage: from 0.395x to 0.630x the memory voltage, in 0.005x increments
• DATA REF Memory Voltage: from 0.395x to 0.630x the memory voltage, in 0.005x increments

Figure 8: overclocking options

Figure 9: memory timing settings

Figure 10: voltage settings

[nextpage title=”Main Specifications”]

The main specifications for the ASUS H81M-A include:

• Socket: LGA1150
• Chipset: Intel H81 Express
• Super I/O: Nuvoton NCT5538D
• Parallel ATA: none
• Serial ATA: two SATA-300 and two SATA-600 ports controlled by the chipset (no RAID support)
• External SATA: none
• USB 2.0: eight USB 2.0 ports, four on the motherboard real panel and four available through two headers on the motherboard
• USB 3.0: two USB 3.0 ports, on the motherboard rear panel, controlled by the chipset
• FireWire (IEEE 1394): none
• Thunderbolt: none
• On-board video: controlled by the CPU; VGA, DVI-D and HDMI connectors
• Audio: produced by the chipset together with a Realtek ALC887 codec (7.1 channels, 24-bit resolution, 192 kHz sampling rate, 97 dB SNR for the outputs, and 90 dB SNR for the inputs)
• On-board LAN: one Gigabit Ethernet port controlled by a Realtek RTL8111G chip
• Buzzer: no
• Infrared interface: no
• Power supply required: ATX12V
• Slots: one PCI Express 3.0/2.0 x16 slot, two PCI Express 2.0 x1 slots
• Memory: two DDR3-DIMM sockets (up to DDR3-1600, 16 GiB maximum)
• Fan connectors: one four-pin connector for the CPU cooler and one four-pin connector for an auxiliary fan
• Extra features: none
• Number of CDs/DVDs provided: one
• Programs included: Motherboard utilities
• More Information: https://www.asus.com/
• Average price in the U.S.*: USD 58.00

* Researched at Newegg.com on the day we published this review.

[nextpage title=”Conclusions”]

Nowadays, Intel offers a wide range of socket LGA1150 processors, including some entry-level models. As such, there is no sense in building a PC with a low-end CPU using a high-end motherboard that uses the flagship Z97 chipset.

The ASUS H81M-A is a typical value motherboard for Intel LGA1150 processors. Based in a basic chipset, it is inexpensive, and this is also reflected in the presence of only two memory sockets (where you must use two identical memory modules to enable the dual-channel mode), and the absence of extra features such as overclocking options, SLI support, etcetera. It also brings a low count of SATA-600 and USB 3.0 ports, since it uses a simple chipset and brings no extra chips to provide more ports. It will not draw the attention of extreme overclockers or gaming enthusiasts.

However, for the user who is looking for an inexpensive motherboard to build a computer based on a low-end Intel socket LGA1150 CPU, with one or two storage units and only one video card, and will not try any overclocking, the ASUS H81M-A has a good cost/benefit ratio.