MSI A75MA-G55 Motherboard
By Gabriel Torres on July 14, 2011


Introduction

So far, MSI has released two motherboard models based on the AMD A75 chipset for the new AMD A-Series of CPUs with integrated graphics chip (“APUs”), the A75A-G35, an ATX model that isn’t sold in the US yet, and the A75MA-G55, a microATX model that is sold for USD 110 in the US. Let’s take a look at the A75MA-G55 model.

AMD released two chipsets for the new socket FM1 platform, the A55 and the A75. Both are single-chip solutions. The A55 is an entry-level solution, supporting six SATA-300 ports, 14 USB 2.0 ports, and four x1 PCI Express lanes. The A75 is a high-end solution, with six SATA-600 ports, four USB 3.0 ports (making it the first chipset with an integrated USB 3.0 controller), eSATA port multiplier (“FIS-based switching,” which allows you to install more than one hard drive to a single SATA port), and the other features found on the A55. Click here to learn more.

MSI A75MA-G55 motherboard
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Figure 1: MSI A75MA-G55 motherboard

Slots

The MSI A75MA-G55 comes with two PCI Express x16 slots, one PCI Express x1 slot, and one standard PCI slot.

The first PCI Express x16 slot is connected directly to the CPU integrated PCI Express controller, and it always works at x16 speed. The second PCI Express x16 slot is connected to four PCI Express lanes on the A75 chipset, so it always works at x4 speed.

If you install a dual-slot video card in the first PCI Express x16 slot, you will “kill” the PCI Express x1 slot, and if you install a dual-slot video card in the second PCI Express x16 slot, you will “kill” the standard PCI slot.

MSI A75MA-G55 motherboard
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Figure 2: Slots

Memory Support

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

The integrated memory controller from socket FM1 processors supports only DDR3 memories, up to 1,866 MHz under dual-channel architecture.

The MSI A75MA-G55 has four memory sockets, and since DDR3 memory modules can now be found in capacities up to 8 GB, you can have up to 32 GB with this motherboard if you use four 8 GB modules.

The first and third sockets are black, while the second and fourth are blue. In order to achieve the maximum performance, you should install two or four memory modules in order to enable dual-channel architecture. When only two modules are used, install them in the black sockets.

MSI A75MA-G55 motherboard
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Figure 3: Memory sockets; install two or four modules for the best performance

On-Board Peripherals

The AMD A75 chipset is a single-chip solution and is also known as an FCH (Fusion Controller Hub). This chip supports six SATA-600 ports with RAID (0, 1, and 10). Four of these ports are installed on the motherboard edge and rotated 90°, so the installation of a video card in any of the PCI Express x16 slots won’t block them. However, the other two ports are installed perpendicular to the motherboard, and the installation of a video card in the second PCI Express x16 slot will block them.

MSI A75MA-G55 motherboard
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Figure 4: SATA-600 ports

There is no support for a floppy disk drive controller or an ATA-133 port.

This motherboard has eight USB 2.0 ports, four soldered on the rear panel and four available through two headers located on the motherboard. It also has four USB 3.0 ports, two available on the motherboard rear panel and two available through a front panel connector, all controlled by the chipset. The MSI A75MA-G55 comes with an I/O bracket with two USB 3.0 ports in order for you to use the two ports available on the motherboard front panel connector if your case doesn’t have USB 3.0 ports or if they don’t use this kind of connector.

There are no FireWire (IEEE1394) 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 of 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 portrayed motherboard comes with independent analog audio outputs, meaning that you won’t need to use the line in or mic in jacks when connecting an eight-channel analog speaker set. The MSI A75MA-G55 doesn’t have an on-board SPDIF output, but you can get digital audio through its HDMI connector, or install the SPDIF connectors using the “JSP1” header. (You need to buy an I/O bracket containing the SPDIF outputs for that.)

This motherboard has one Gigabit Ethernet port controlled by a Realtek RTL8111E controller.

In Figure 5, you can see the motherboard rear panel, with a shared keyboard/mouse PS/2 connector, four USB 2.0 ports, HDMI connector, VGA connector, DVI-D connector, one Gigabit Ethernet port, two USB 3.0 ports (blue connectors), and independent analog 7.1 audio outputs.

MSI A75MA-G55 motherboard
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Figure 5: Motherboard rear panel

Other Features

The motherboard has a legacy serial port on a header labeled “JCOM1” and a parallel port on a header labeled “JLPT1.” You will need to buy adapters if you want to use these ports. It also supports the installation of a TPM (Trusted Platform Module), which increases security by encrypting data that is handled by the system.

In Figure 6, you can see all the accessories that come with this motherboard.

MSI A75MA-G55 motherboard
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Figure 6: Accessories

Voltage Regulator

The CPU voltage regulator circuit of the MSI A75MA-G55 has three phases for the CPU main voltage (VDD a.k.a. Vcore), one for the CPU VDDNB voltage (integrated memory controller), and two for the CPU VDDP voltage (integrated video controller). Therefore, it uses a “3+1+2” configuration.

MSI A75MA-G55 motherboard
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Figure 7: Voltage regulator circuit

MSI A75MA-G55 motherboard
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Figure 8: Voltage regulator circuit

This motherboard uses solid ferrite-core coils, which present less energy loss than iron-core coils (i.e., they improve efficiency), solid capacitors, and low RDS(on) transistors (i.e., higher efficiency).

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

Overclocking Options

The MSI A75MA-G55 offers a few overclocking options, listed below (1.0 BIOS):

For a better understanding of what these options do, please read our Understanding All Voltage Configurations from the Motherboard tutorial.

MSI A75MA-G55 motherboard
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Figure 9: Overclocking options

Main Specifications

The main specifications for the MSI A75MA-G55 motherboard include:

* Researched at Newegg.com on the day we published this First Look article.

Conclusions

The MSI A75MA-G55 is clearly an entry-level motherboard for the new A-Series CPUs from AMD. The main problem with this motherboard is competition. The Gigabyte A75M-UD2H is found in the same price range (actually, it is USD 10 cheaper than this model from MSI at Newegg.com) and comes with far more features: a better audio codec, an on-board optical SPDIF output, two FireWire (IEEE1394) ports, a DisplayPort video output, one eSATA-600 port, and more overclocking options. Therefore, between the two, the Gigabyte A75M-UD2H is a better option. 

Originally at http://www.hardwaresecrets.com/article/MSI-A75MA-G55-Motherboard/1338


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