ASRock FM2A85X-ITX Motherboard
By Gabriel Torres on February 22, 2013


Introduction

The ASRock FM2A85X-ITX is a Mini-ITX motherboard based on the most high-end chipset for the socket FM2 platform, the A85X (codenamed “Hudson D4”). It is targeted to the second-generation APUs from AMD, codenamed “Trinity.” Let’s see what this motherboard has to offer.

APU is a name that AMD coined for their CPUs with integrated video. They are also known as “A-series,” as models start with the letter “A” (A4, A6, A8, and A10).

Currently, there are three chipsets available for the socket FM2 platform: A85X, A75, and A55. The A75 and A55 chipsets were released in 2011 with the socket FM1 platform, which is used by the first-generation of APUs from AMD. The A85X is a new chipset, released with the second-generation APUs. In the table below, we compare the main differences between these three chipsets. As you can see, the main difference between the A85X and the A75 is the addition of two more SATA-600 ports on the A85X.

Feature

A85X

A75

A55

PCI Express 2.0 x1

4

4

4

USB 1.1

2

2

2

USB 2.0

10

10

14

USB 3.0

4

4

0

SATA-300

0

0

6

SATA-600

8

6

0

FIS-Based Switching

Yes

Yes

No

UMI

2 GB/s

2 GB/s

2 GB/s

“FIS-based switching” is an eSATA port multiplier technology, which allows you to install more than one hard drive to a single SATA port. Click here to learn more. UMI stands for Unified Media Interface; it is the interface that connects the CPU to the chipset.

AMD APUs have an embedded PCI Express 2.0 controller, with one PCI Express 2.0 x16 port and four PCI Express 2.0 x1 ports. Second-generation APUs allow the x16 port to be divided into two x8 ports. It is important to understand that this is a feature provided by the processor, not by the chipset.

The ASRock FM2A85X-ITX doesn’t support the Virtu Universal MVP, which allows you to combine the performance of the integrated graphics processor available in the CPU with the performance of any video card installed, a feature that is available on some socket FM2 motherboards.

So far, ASRock has released four motherboards based on the A85X chipset; the FM2A85X-ITX is the only one using the Mini-ITX form factor. See table below. Prices were researched at Newegg.com on the day we published this article.

Specification

FM2A85X-ITX

FM2A85X Extreme4-M

FM2A85X Extreme4

FM2A85X Extreme6

Form Factor

Mini-ITX

microATX

ATX

ATX

Memory Sockets

2

4

4

4

PCI Express 2.0 x16

1

2 (x16/x4)

2 (x16/x4)

3 (x16/x0/x4 or x8/x8/x4)

PCI Express 2.0 x1

0

1

2

2

Standard PCI

0

1

3

2

CrossFireX

No

Yes

Yes

Yes

SLI

No

No

No

No

SATA-300

0

0

0

0

SATA-600

7

7

7

7

eSATA-300

0

0

0

0

eSATA-600

1

1

1

1

USB 2.0

8

10

8

8

USB 3.0

4

4

8

6

FireWire

0

0

0

0

Gigabit Ethernet

1

1

1

1

VGA

Yes

Yes

Yes

Yes

DVI-D

Yes

Yes

Yes

Yes

HDMI

Yes

Yes

Yes

Yes

DisplayPort

No

No

No

Yes

Audio

ALC892

ALC892

ALC892

ALC898

Voltage Regulator

4+2

4+2

4+2

8+2

Price

USD 100

USD 90

USD 95

USD 110

In Figure 1, you see the ASRock FM2A85X-ITX motherboard, which is based on the Mini-ITX form factor (6.7 x 6.7 inches or 170 x 170 mm).

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 1: ASRock FM2A85X-ITX motherboard

Slots

Since it is a Mini-ITX motherboard, the ASRock FM2A85X-ITX comes with only one PCI Express 2.0 x16 slot.

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 2: PCI Express x16 Slot

Memory Support

AMD 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 FM2 processors supports DDR3 memories up to 1,866 MHz. According to ASRock, the FM2A85X-ITX supports memories up to DDR3-2400.

The ASRock FM2A85X-ITX has only two memory sockets. According to the manufacturer, it supports up to 32 GB if two 16 GB memory modules are used.

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

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 3: Memory sockets; install two identical modules for the best performance

On-Board Peripherals

The AMD A85X chipset is a single-chip solution. This chip supports eight SATA-600 ports with RAID (0, 1, 10, and 5). On the ASRock FM2A85X-ITX, one of them was placed on the rear panel as an eSATA-600 port, leaving seven SATA-600 ports available.

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 4: SATA-600 ports

The AMD A85X chipset supports two USB 1.1 ports, 10 USB 2.0 ports, and four USB 3.0 ports. The ASRock FM2A85X-ITX offers eight USB 2.0 ports, four soldered on the rear panel and four available through two headers located on the motherboard; and four USB 3.0 ports, two located on the motherboard rear panel and two available on a header located on the motherboard.

The ASRock FM2A85X-ITX doesn’t have FireWire ports.

This motherboard supports 7.1+2 audio format, i.e., eight channels plus two independent channels for audio streaming. On this motherboard, the audio is generated by the chipset using the Realtek ALC892 codec, which is a mainstream-grade product, providing a 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 specifications are good for the average user, but if you want to work professionally with audio editing or converting analog audio sources into digital format, you will need to pick a motherboard with at least 100 dB signal-to-noise ratio for its inputs.

The motherboard has on-board optical SPDIF output. A header labeled “HDMI_SPDIF1” also provides SPDIF output for you to install a coaxial SPDIF output or to route digital audio to older video cards that require this physical connection in order to have digital audio output in their HDMI connectors.

The analog audio outputs allow you to install a 5.1 analog speaker set without using the “mic in” or the “line in” jacks, but if you install an analog 7.1 speaker set, you will need to use one of them for the center surround speakers.

The portrayed motherboard has one Gigabit Ethernet port controlled by a Realtek RTL8111E chip.

In Figure 5, you can see the motherboard rear panel with a shared keyboard/mouse PS/2 connector, four USB 2.0 ports, VGA output, DVI-D output, HMDI output, one eSATA-600 port, a Gigabit Ethernet port, two USB 3.0 ports, an optical SPDIF output, and the analog audio jacks.

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 5: Motherboard rear panel

Other Features

The ASRock FM2A85X-ITX has an infrared interface, making it inexpensive for you to add an infrared sensor to be able to use a remote control or to connect devices using infrared technology (IrDA).

In Figure 6, you can see all of the accessories that come with the ASRock FM2A85X-ITX.

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 6: Accessories

Voltage Regulator

The CPU voltage regulator circuit of the ASRock FM2A85X-ITX has four phases for the CPU main voltage (VDD or Vcore) and two for the CPU memory controller (VDDNB). Therefore, it uses a “4+2” configuration. The voltage regulator is controlled by an ISL6377 integrated circuit.

Each phase is driven by a CSD87350Q5D integrated circuit, which incorporates the “high side” and “low side” transistors, providing higher efficiency than discrete solutions.

ASRock FM2A85X-ITX
click to enlarge
Figure 7: Voltage regulator circuit

The ASRock FM2A85X-ITX uses solid electrolytic capacitors, and one SMD (a.k.a. highly-conductive polymerized or simply Hi-c) capacitor per phase. All coils on this motherboard are high-end ferrite-core models, which can provide up to 20% improvement in efficiency.

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

Overclocking Options

The ASRock FM2A85X-ITX provides a few overclocking options. Below, we list the most important ones available at the motherboard’s setup (1.20 BIOS):

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 8: Overclocking options

ASRock FM2A85X-ITX Motherboard
click to enlarge
Figure 9: Overclocking options

Main Specifications

The main specifications for the ASRock FM2A85X-ITX include:

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

Conclusions

The ASRock FM2A85X-ITX is a good motherboard if you are building a small form factor (SFF) computer using a second-generation A-Series CPU from AMD (“Trinity”). It only has the basic features provided by the chipset, but these (seven SATA-600 ports, one eSATA-600 port, four USB 3.0 ports, and eight USB 2.0 ports) are more than enough for the average user. With VGA, DVI-D, HDMI, and optical SPDIF connectors available, you won’t have any trouble connecting a computer built with this motherboard to a home theater system. ASRock used high-end components on the motherboard’s voltage regulator circuit, which is always nice to see.

We think the price for this motherboard is right for what it offers, and it should please the average user building a small form factor computer either for gaming, for regular office applications, or as a media center.

Originally at http://www.hardwaresecrets.com/article/ASRock-FM2A85X-ITX-Motherboard/1735


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