Gigabyte H55N-USB3 Motherboard
By Rafael Coelho on December 21, 2010


Today we are taking a look at the H55N-USB3, a mini-ITX socket LGA1156 motherboard from Gigabyte based on the Intel H55 chipset, allowing you to build a mainstream computer in an SFF (Small Form Factor) case. Let's check it out.

Frequently mini-ITX motherboards come with embedded low-consuption CPUs, like the Intel Atom, and they are used in computers where the focus is size and power consumption, not performance. But the H55N-USB3 is an exception: it accepts any socket LGA1156 CPU, like the Core i3, Core i5 and even some Core i7 models. It also brings one PCI Express x16 slot, which allows you to install even a high-end video card (if it fits your case), and two USB 3.0 ports.

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Figure 1: Gigabyte H55N-USB3 motherboard


One of the main features of socket LGA1156 processors is the presence of an integrated PCI Express 2.0 controller inside the CPU. This controller supports one x16 connection or two x8 connections. The Intel P55 chipset provides a total of eight x1 PCI Express lanes.

Due to its reduced size, the Gigabyte H55N-USB3 has only one expansion slot, a PCI Express x16. Keep in mind that this slot accepts x1, x4 and x8 cards.

Of course the H55N-USB3 can't support CrossFireX or SLI configurations.

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Figure 2: Slot

Memory Support

Socket LGA1156 CPUs, like socket LGA1366 and AMD processors, have an embedded memory controller. This means that it is the processor – and not the chipset – that defines what memory technologies and maximum amount of memory you can have. The motherboard, however, may have a limitation as to how much memory can be installed.

At the moment the integrated memory controller in socket LGA1156 processors supports only DDR3 memories up to 1,333 MHz in a dual-channel architecture, however, Gigabyte says the H55N-USB3 supports DDR3 memories up to 1,666 MHz through overclocking. The H55N-USB3 has two DDR3 sockets and since at the moment each DDR3 memory module can have up to 4 GB, you can have up to 8 GB with this motherboard.

Since there are two memory sockets, you need to populate both of them in order to achieve the maximum possible performance, by enabling dual-channel architecture.

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Figure 3: Memory modules, install two modules for the best performance

On-Board Peripherals

The Intel H55 chipset is a single-chip solution. The basic features provided by this chipset include six SATA-300 ports (RAID support is optional), no support for parallel ATA (PATA) ports, 14 USB 2.0 ports supporting port disable, an embedded Gigabit Ethernet MAC (Medium Access Control), and eight x1 PCI Express lanes.

The Gigabyte H55N-USB3 provides five SATA-300 ports, with no RAID support. Four of them are available as standard SATA ports and one is available as an eSATA-300 port at the rear panel.

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Figure 4: SATA ports

No ATA-133 port or floppy disk drive controller are present.

From the 14 USB 2.0 ports supported by the chipset, the H55N-USB3 offers eight of them, four soldered at the rear panel and four available through two motherboard headers.

One of the highlights of this motherboard is the presence of two USB 3.0 ports, controlled by a NEC μPD720200F1 chip, available at the rear panel of the product.

No FireWire port is available.

Audio is generated by the chipset using a Realtek ALC892 codec. Unfortunately this component is not listed on the manufacturer website, so we can't discuss the audio quality. This motherboard comes with an on-board optical SPDIF output.

This motherboard uses independent 7.1 analog audio outputs, meaning that you can have an eight-channel analog speaker set without "killing" the line in or mic in jacks.

The Gigabyte H55N-USB3 has one Gigabit Ethernet port, controlled by a Realtek RTL8111E chip, which is connected to the system using a PCI Express x1 lane, and thus not presenting any potential performance issues.

This motherboard supports CPUs with integrated video, with three different connectors, VGA, DVI-D, and HDMI. If you install a CPU without embedded video (a Core i7 or some Core i5 models), you must install an add-on video card, as the motherboard has no video controller: the video connector are installed on the video controller embedded in the CPU.

In Figure 5, you can see the motherboard rear panel with a shared PS/2 mouse/keyboard connector, VGA, DVI, and HDMI outputs, four USB 2.0 ports, one eSATA-300 port, one Gigabit Ethernet port, two USB 3.0 ports (blue), independent 7.1 analog audio connectors, and an optical SPDIF output.

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Figure 5: Motherboard rear panel

Additional Features

The Gigabyte H55N-USB3 has a few additional smaller features. It has two BIOS chips, so in case the main BIOS gets corrupted by a bad BIOS upgrade or a virus, you can easily restore the contents of the ROM chip and prevent your motherboard from becoming “dead.”

The USB ports have fuses to prevent you from burning your motherboard if somehow the ground and VCC pins from the USB ports are reversed, touch each other, or the USB ports get a really high static discharge. In Figure 6, you can see one of these fuses.

Gigabyte H55N-USB3
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Figure 6: Fuse

This motherboard comes a standard accessories set, which you can see in Figure 6. There is a drivers/utilities DVD, SATA and ATA cables (why an ATA cable was included is a mystery, since this motherboard doesn't have an ATA port), I/O shield for the case, stickers and manuals.

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Figure 7: Accessories

Voltage Regulator

The H55N-USB3 comes with a very good seven-phase voltage regulator circuit for the CPU. Four of them are used for CPU main voltage (Vcc, a.k.a. Vcore), two of them are used for the VTT rail, which feeds the CPU integrated memory controller and L3 memory cache, and the last one is used for the integrated video controlled (VAXG). Therefore, this motherboard has a "4+2+1" configuration.

The MOSFET transistors used in the CPU main power voltage regulator circuit are the NTMFS4921N and NTMFS4935N ("high side" and "low side"), using the ISL6612 and ISL6622 as drivers. They are low RDS(on) MOSFETs, which means this circuit has higher efficiency than regular MOSFETs.

The CPU memory controller (VTT) and the and the memory modules (VDIMM) phases also uses low-RDS(on) MOSFET transistors.

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Figure 8: Voltage regulator circuit

All electrolytic capacitors used on this motherboard are solid, and the board uses only ferrite-core coils, which present less energy loss than iron-core coils (i.e., they improve efficiency).

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

Continuing Gigabyte's tradition, the H55N-USB3 uses thicker copper tracks on the printed circuit board VCC and GND tracks. Usually the printed circuit board power tracks are 35 µm thick, but on this motherboard the power tracks are 70 µm thick. This feature is also called “2 oz. copper tracks” by the manufacturer.

A series of three LEDs show which phases are currently active.

Gigabyte H55N-USB3
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Figure 9: Active phases LEDs

Overclocking Options

Surprisingly, the H55N-USB3 has a lot of overclocking options. The main overclocking options we could see in the motherboard setup were:

The memory timings can also be tweaked.

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Figure 10: Overclocking menu

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Figure 11: Overclocking menu (Cont’d)

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Figure 12: Memory timings

Main Specifications

The main specifications for the Gigabyte H55N-USB3 are:

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


The Gigabyte H55N-USB3 differs from other mini-ITX motherboard we have seen so far, not only because several motherboards that use this form factor bring a low consuption (and thus, low performance) CPU soldered on it, but because the H55N-USB3 have a lot of features we are used to see only on high-end motherboards.

Of course, there are features the manufacturer could not put on this motherboard just because of the lack of room for them, like more than one PCI Express x16 slot, four memory sockets, a voltage regulator circuit with dozen of phases, etc.

In short, if you want to build an SFF computer, but you don't want to leave the performance of a mainstream CPU, upgradeability, overclocking possibilities, you will be satisfied with the Gigabyte H55N-USB3.


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