Introduction

Intel has released three different socket 1156 motherboard models based on their new Intel P55 chipset. Today we are going to take a look at their most high-end model, DP55KG, which includes some interesting features like a Bluetooth antenna.

DP55KG, like all motherboards from Intel, has a very sober looks, all black with a few blue plastic parts. The passive heatsinks from the voltage regulator circuit are also blue. The first thing we notice about this motherboard is that all capacitors from the voltage regulator circuits are solid. The other capacitors are either Japanese from Chemi-Con or Nichicon, or Chinese from Samxon.

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Figure 1: Intel DP55KG motherboard.

One of the main new features from socket 1156 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. Usually on P55-based motherboards the manufacturer puts two PCI Express 2.0 x16 slots on the board, with the first slot working at x16 when only one video card is used or both slots working at x8 when two video cards are used.

With DP55KG Intel decided to use a physical x8 slot for the second video card. Since this particular slot has its end opened, you can install an x16 video card on it. The x16 slot and the x8 slot are blue, probably to remind us that they are controlled by the CPU. The remaining slots are black and controlled by the chipset. DP55KG bring one x4 PCI Express slot with its end opened as well, meaning that a third video card can be installed on this motherboard (working at x4 obviously). DP55KG also has two x1 PCI Express slots and two standard PCI slots.

DP55KG supports both CrossFire and SLI configurations. Keep in mind that SLI support on P55-based motherboards will depend on whether the manufacturer licensed this technology from NVIDIA or not, i.e., not all P55-based motherboards have SLI support.

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Figure 2: Slots.

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Figure 3: See how the x8 and x4 slots have their ends opened.

You can notice in Figure 2 a SATA power connector near the motherboard edge. The installation guide doesn’t mention this connector and we assume that it is used to provide more current to the PCI Express slots and thus it is a good idea to connect it to the power supply.

Memory Support

Socket 1156 CPUs, like socket 1366 and AMD processors, have an embedded memory controller. All other Intel CPUs use an external memory controller, which is located on the north bridge chip (a.k.a. MCH or Memory Controller Hub) from the chipset. This means that with other Intel CPUs the chipset (and thus the motherboard) is the component that says what memory technologies and the maximum amount of memory you can have on your PC.

Since now the memory controller is inside the CPU, it is the processor, and not the chipset, that defines the 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.

At the moment, the integrated memory controller of socket 1156 processors supports only DDR3 memories up to 1,333 MHz under dual-channel architecture, however Intel says DP55KG supports DDR3 memories up to 1600 MHz. DP55KG has four DDR3 sockets and since each DDR3 memory module can have up to 4 GB, you can have up to 16 GB with this motherboard.

The first and the third sockets are black, while the second and the fourth are blue. In order to achieve the maximum performance, you should install two or four memory modules to enable the dual-channel architecture. When only two modules are used make sure to install them on the blue sockets. If you install them on the black ones the computer won’t turn on and the POST display will show “21” code while the motherboard will be beeping.

Figure 4: Memory sockets. Install two or four modules for the best performance.

On-Board Peripherals

Intel P55 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, embedded Gigabit Ethernet MAC (Medium Access Control) and eight x1 PCI Express lanes.

Intel DP55KG provides all the six SATA-300 ports suporting RAID 0, 1, 5 and 10, plus two extra SATA-300 ports controlled by a Marvell 88E6145 chip. This chip also controls two eSATA-300 ports present on the rear panel from the motherboard.

The SATA connectors are placed facing the motherboard edge, as you can see in Figure 5. This is a terrific solution, because on motherboards where the ports are facing up the video cards usually block the access to them or even completely prevent you from installing SATA cables on them.

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Figure 5: SATA ports.

Since Intel P55 chipset does not provide parallel ATA port and Intel DP55KG doesn’t have any additional PATA controller chip, this motherboard doesn’t have any parallel ATA port. It also lacks a floppy disk drive controller.

From the 14 USB 2.0 ports supported by the chipset, 13 are present on this motherboard, eight soldered on the rear panel, one soldered on a different position near the rear panel (see Figure 6) and four available through two motherboard headers. Additionally Intel DP55KG motherboard comes with a FireWire (IEEE 1394) controller, providing two FireWire ports, one soldered on the rear panel and one available a header.

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Figure 6: USB port on an unusual place.

Audio is generated by the chipset using a Realtek ALC889 codec, which is a professional-grade component, providing 7.1 audio with 24-bit resolution, 108 dB signal-to-noise ratio for the outputs, 104 dB signal-to-noise ratio for the analog inputs and 192 kHz sampling rate for both the outputs and inputs. This motherboard comes with an on-board optical SPDIF output and input, which is terrific – most motherboards with on-board SPDIF connectors come only with outputs, not inputs. The board also has an SPDIF out header, so you can install a bracket containing a coaxial SPDIF output if you need one (this device doesn’t come with the board). As you can see in Figure 8, this motherboard has independent analog outputs for all eight channels. With these specs you work professionally with audio editing and mixing without the need of a high-end (and expensive) add-on sound card.

Intel DP55KG has a Gigabit Ethernet port controlled by the chipset and using an Intel 82578DC chip to make the interface with the physical layer.

As briefly mentioned on the introduction, Intel DP55KG comes with a Bluetooth controller. To use it you need to install the antenna that comes with the motherboard.

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Figure 7: Bluetooth controller with antenna installed.

This motherboard comes with an on-board infrared controller, so if you want to use this feature you will need to buy the receiver and transmitter LEDs, which don’t come with the product.

In Figure 8, you can see the motherboard rear panel with two eSATA-300 ports, button for the Back2BIOS function, optical SPDIF input and output, eight USB 2.0 ports, FireWire port, Gigabit Ethernet port and independent analog 7.1 audio outputs.

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Figure 8: Motherboard rear panel.

The Back2BIOS is a pretty ingenious function added by Intel. When this button is pressed, it glows red and the motherboard will automatically enter the BIOS setup during the next boot. This is a very useful function for overclockers.

As you can see, this motherboard does not come with PS/2 connectors for mouse or keyboard, so you must use a USB mouse and a USB keyboard with this motherboard.

Other Features

Intel DP55KG has several other smaller features. For example, when you turn on the computer, the skull printed on the motherboard lights up in red.

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Figure 9: Skull lights up when you turn on the motherboard.

DP55KG comes with a POST display, which helps you to diagnose why the computer isn’t turning on through a two-digit number.

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Figure 10: POST diagnostics display.

It also has a power button soldered on the motherboard, which helps a lot when you are building a PC outside a case or are debugging your PC.

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Figure 11: Power button.

Overclocking Options

Intel DP55KG offers some overclocking options. The main options we could see with the initial BIOS release (86A.3456) were:

• CPU base clock: can be adjusted from 133 MHz to 240 MHz in 1 MHz increments.
• PCI Express clock: can be adjusted from 100 MHz to 110 MHz in 1 MHz increments.
• CPU voltage: From 1.0 V to 2.3 V in 0.0125 V increments.
• Memory voltage: From 1.3 V to 2 V in 0.01 V increments.
• Memory controller voltage: From 1.1 V to 1.8 V in 0.01 V increments.
• Chipset (PCH) voltage: From 1.03 V to 1.5 V in 0.01 V increments.

Memory timings can also be tweaked. Intel DP55KG also offers detailed configuration for the CPU Turbo Boost mode.

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Figure 12: Overclocking menu.

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Figure 13: Turbo Boost tweaking.

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Figure 14: Memory timing options.

Main Specifications

Intel DP55KG motherboard main features are:

• Socket: 1156.
• Chipset: Intel P55 Express.
• Super I/O: Winbond W83677HG
• Clock generator: SLG505YC264CT
• Parallel IDE: None.
• Serial IDE: Eight SATA-300 ports, six controlled by the chipset (RAID 0, 1, 5 and 10) and two controlled by a Marvell 88SE6145 chip.
• External ATA: Two eSATA-300 ports controlled by the Marvell 88SE6145 chip.
• USB: 13 USB 2.0 ports (nine soldered on the motherboard and four available through headers on the motherboard).
• FireWire (IEEE 1394): Two ports controlled by a Texas Instruments TSB43AB22A chip, one standard-sized soldered on the rear panel and one available through a header.
• On-board audio: Produced by the chipset together with a Realtek ALC889 codec (eight channels, 24-bit resolution, up to 192 kHz sampling rate for both the inputs and outputs, 104 dB signal-to-noise ratio for the inputs and 108 dB signal-to-noise ratio for the outputs). On-board optical SPDIF input and output.
• On-board LAN: One Gigabit Ethernet port controlled by the chipset using an Intel 82578DC to make the physical layer interface.
• Buzzer: Yes.
• Power supply required: EPS12V.
• Slots: One PCI Express 2.0 x16 slot (working at x8 when two video cards are installed), one PCI Express x8 slot, one PCI Express x4 slot, two PCI Express x1 slots and two standard PCI slots.
• Memory: Four DDR3-DIMM sockets (up to 16 GB up to DDR3-1600/PC3-12800).
• Number of CDs/DVDs provided: One.
• Programs included: Motherboard drivers and utilities.
• Extra features: Aluminum solid capacitors on the voltage regulator circuit, POST diagnostics display, Bluetooth controller, infrared controller, Back2BIOS button.
• More Information: http://www.intel.com
• Average price in the US*: USD 210.00

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

Conclusions

Intel DP55KG has lot of extra features compared to mainstream P55-based motherboards, especially the support for SLI configuration, support for three video cards, on-board Bluetooth controller, two additional SATA-300 ports, two eSATA-300 ports, on-board optical SPDIF input and output, FireWire ports and professional-grade on-board audio.

Although it is more expensive than mainstream products, it is not badly priced if you really need the extra features it brings. Of course if the extras won’t make any difference for you, you should stick with a mainstream model and save some money.