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[nextpage title=”Introduction”]

Right now MSI has 14 different motherboard models based on the Intel P55 chipset. Let’s take a look at the P55A-GD65 (a.k.a. MS-7585), a stripped-down version of their P55-GD85.

By the way, we’ve already covered two other motherboards from MSI based on the same chipset, the P55-GD80 and the P55-GD85.

MSI uses a naming scheme where the higher the number on the product name, the more features it carries. So the P55A-GD65 doesn’t have the same amount of features present on the other two models that we’ve already covered, but that doesn’t mean it is a low-end product – far from it.

Be sure not to confuse the new P55A-GD65 with an older model called the P55-GD65 (without the “A”). Despite the name, the two are completely different products:

  • The new P55A-GD65 comes with two SATA-600 ports and two USB 3.0 ports, features not present on the P55-GD65.
  • The P55-GD65 has two heatsinks on the voltage regulator circuit and a heatpipe connecting them, while on the P55A-GD65, one of the heatsinks was removed, along with the heatpipe.
  • The position of the slots is completely different, plus the P55-GD65 had one PCI Express x4 slot, which was removed on the P55A-GD65.
  • The previous incarnation had a place for measuring voltages with a multimeter, a feature that was removed on the new product.

In fact, the P55A-GD65 is a stripped-down version of the P55-GD85. Both have the same layout, but on the new GD65 the second voltage regulator heatsink and its heatpipe, second Gigabit Ethernet port, voltage measuring points, and SLI support were removed.

MSI P55A-GD65 motherboardFigure 1: MSI P55A-GD65 motherboard

[nextpage title=”Slots”]

One of the main new features from 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. MSI P55A-GD65 has two PCI Express x16 slots using this configuration. They support CrossFireX, but not SLI. Keep in mind that SLI support on P55-based motherboards will depend on whether the manufacturer licensed this technology from NVIDIA or not.

The other PCI Express slots are controlled by the chipset, which has a total of eight PCI Express x1 lanes. A small but very important detail is that MSI added a PLX PEX8608 PCI Express switch chip on this motherboard (see this chip near the black PCI Express x1 slot in Figure 2), which adds eight more PCI Express x1 lanes to it. The presence of this chip allows you to run two high-end video cards, SATA-600 hard disk drives and USB 3.0 devices at the same time without any drop in performance. On motherboards without a chip like this, performance may drop under this type of load, as the chipset doesn’t have enough PCI Express lanes to connect all these devices at the same time at their full speed.

This motherboard has two PCI Express x1 slots and two standard PCI slots. The older P55-GD65 model has one PCI Express x4 slot, but the main difference between these two motherboards is the placement of the available slots. As you can see in Figure 2, MSI put the standard PCI slots between the two x16 PCI Express slots. On the original P55-GD65 you automatically “kill” one of the PCI Express x1 slots whenever you install a dual-slot video card in the first PCI Express x16 slot, a thing that doesn’t happen with this motherboard.

The slot configuration used on the P55A-GD65 is identical to the configuration used on the P55-GD85. The only difference between the two here is that the GD85 supports SLI, while the GD65 doesn’t.

MSI P55A-GD65 motherboardFigure 2: Slots

[nextpage title=”Memory Support”]

Socket LGA1156 CPUs, like socket 1136 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 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.

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, MSI says the P55A-GD65 supports DDR3 memories up to 2133 MHz through overclocking. The P55A-GD65 has four DDR3 sockets and since at the moment each DDR3 memory module can have up to 4 GB, you can have up to 16 GB with this motherboard.

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, make sure to install them in the black sockets. If you install them in the blue ones, the computer won’t turn on.

MSI P55A-GD65 motherboardFigure 3: Memory sockets; install two or four modules for the best performance

[nextpage title=”On-Board Peripherals”]

The 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, an embedded Gigabit Ethernet MAC (Medium Access Control), and eight x1 PCI Express lanes. As explained, this motherboard has a PLX PEX8608 chip that adds another eight  x1 PCI Express lanes.

MSI P55-GD65 provides all the six SATA-300 ports with support for Intel Matrix Storage, which provides RAID 0, 1, 5, and 10 (these ports are black). A seventh SATA-300 port (blue) is available, controlled by a JMicron JMB363 chip, which also controls the eSATA-300 port available on the rear panel. This eSATA port is shared with a USB 2.0 port. This motherboard also has two white SATA-600 ports (a.k.a. SATA 6 G), controlled by a Marvell 88SE9128 chip that provides support for RAID 0 and 1.

Even though the chipset doesn’t support parallel ATA (PATA, a.k.a. IDE) ports, this motherboard has one ATA-133 port, controlled by the same JMicron JMB363 chip. This port and the six ports controller by the chipset are placed on the motherboard edge rotated 90°, so video cards won’t block them. The other SATA ports are placed where expansion cards won’t block them either.

MSI P55A-GD65 motherboardFigure
4:
ATA-133 port and SATA ports

No floppy disk drive controller is present.

From the 14 USB 2.0 ports supported by the chipset, the MSI P55A-GD65 offers 12 of them, six soldered on the rear panel and six available through three motherboard headers.

One of the highlights of this motherboard is the presence of two USB 3.0 ports, controlled by a NEC μPD720200 chip. These ports are available on the rear panel of the product and painted blue (USB 2.0 ports are black).

Additionally, the MSI P55A-GD65 comes with a FireWire (IEEE 1394) controller, providing two FireWire ports, one soldered on the rear panel and one available through a header. The motherboard doesn’t come with an I/O bracket for you to use the second FireWire port. So if you decide to buy this motherboard, it is a good idea to buy a case with four USB ports and one FireWire port, so you can use all available ports.

Audio is generated by the chipset using a Realtek ALC889 codec (the same used on the original GD65, on the GD80, and on the GD85), which provides professional-grade audio to this motherboard, with eight channels, 24-bit resolution, a sampling rate of up to 192 kHz for both inputs and outputs, 104 dB signal-to-noise ratio for the analog inputs, and 108 dB signal-to-noise ratio for the outputs. With a high signal-to-noise ratio like this you can work professionally, converting, mixing, and editing audio from an analog source (e.g. converting VHS tapes and vinyl records to the digital format) with no background noise (white noise). This motherboard comes with on-board optical and coaxial SPDIF outputs. The board also has an SPDIF-out header (labeled “JSP1”), which can be used to route sound to the video card HDMI output in order for you to have an HDMI output with digital audio on a single connector. As you can see in Figure 5, this motherboard has fully independent analog outputs for all eight audio channels.

The MSI P55A-GD65 has one Gigabit Ethernet port, controlled by one Realtek RTL8111DL chip, which is connected to the system using PCI Express x1 lanes, and thus not presenting any potential performance issues.

In Figure 5, you can see the motherboard rear panel with PS/2 mouse and keyboard connectors, a clear CMOS button, coaxial and optical SPDIF outputs, a FireWire port, six USB 2.0 ports, one eSATA-300 port (shared with one of the USB 2.0 ports), one Gigabit Ethernet port, two USB 3.0 ports (blue ones), and independent analog 7.1 audio outputs.

MSI P55A-GD65 motherboardFigure 5: Motherboard rear panel

There are other smaller features. For example, this motherboard comes with an operating system stored inside the motherboard read-only memory that allows you to access the Internet without needing to load the operating system or even without having a hard disk drive installed. This feature, called Winki, is identical in concept to the Express Gate feature available on motherboards from ASUS and the eJiffy feature present on motherboards from ECS.

This board comes with some overclocking-related hardware features that we will explore later.[nextpage title=”Voltage Regulator”]

The MSI P55A-GD65 comes with a high-end voltage regulator circuit called DrMOS, with a total of ten phases, eight for the CPU (Vcore) and two for the integrated memory controller (VTT rail).

Each phase doesn’t use discrete MOSFET transistors, but integrated circuits containing these transistors. Each “DrMOS” chip (Fairchild FDMF6704V) features three MOSFETs inside (“high side,” “low side,” and the driver) switching at 1 MHz, instead of the 250 kHz of traditional voltage regulators, in order to increase efficiency (i.e., less energy is wasted, causing the CPU and memory to pull less energy from the power supply compared to other designs). According to MSI one “DrMOS” phase is more efficient than four traditional phases because of that design. The manufacturer promises efficiency up to 96%, an increase of 38% over the traditional design.

This motherboard comes with a passive heatsink on top of only four of those integrated circuits. The removal of one of the heatsinks and the heatpipe was one way the manufacturer found to reduce costs, reducing the motherboard price.

All capacitors used on the voltage regulator circuit and on the rest of the motherboard are solid and all chokes are ferrite models, which are better than iron chokes.

Please read our Everything You Need to Know About the Motherboard Voltage Regulator tutorial for more information.

MSI P55A-GD65 motherboardFigure 6: Voltage regulator circuit

MSI P55A-GD65 motherboardFigure 7: Close-up of the voltage regulator circuit

Besides having a high-end voltage regulator circuit, the P55A-GD65 can disable phases from the voltage regulator circuit as needed in order to save energy, a feature called APS (Active Phase Switching). A group of LED’s near the memory sockets indicate how many phases are active at any given moment.[nextpage title=”Overclocking Options”]

The MSI P55A-GD65, like several other models from MSI, has an overclocking function called “OC Genie.” When this button is pressed, the motherboard automatically overclocks the system (it must be pressed when the computer is turned off). Previous automatic overclocking functions available from MSI and other manufacturers increased the base clock to preset values. OC Genie relies on a chip that overclocks the system on-the-fly, based on your hardware configuration. You can also manually increase or decrease the CPU base clock in 1 MHz steps by simply pressing “+” and “-” buttons located on the board.

In Figure 8 you can see all buttons available on this motherboard, OC Genie, the “+” and “-” buttons, reset and power.

MSI P55A-GD65 motherboardFigure 8: Buttons

The main overclocking options we could see in the motherboard setup were:

  • CPU base clock: Can be adjusted from 100 MHz to 600 MHz in 1 MHz increments
  • PCI Express clock: Can be adjusted from 90 MHz to 190 MHz in 1 MHz increments
  • CPU voltage: From 0.9 V to 2.1 V in 0.006 V increments
  • CPU VTT voltage: From 0.451 V to 2.018 V in 0.006 V increments
  • Memory voltage: From 0.300 V to 2.400 V in 0.015 V increments
  • Chipset main voltage (PCH 1.05): From 0.451 V to 1.953 V in 0.005 V increments
  • Chipset PLL voltage (PCH 1.8): From 1.000 V to 2.400 V in 0.05 V increments
  • Memory data reference voltage: From 0.450 V to 1.150 V in 0.025 V increments (for each channel)
  • Memory control reference voltage: From 0.450 V to 1.150 V in 0.025 V increments (for each channel)

MSI P55A-GD65 motherboardFigure 9: Overclocking menu

MSI P55A-GD65 motherboardFigure 10: Overclocking menu (Cont’d)

These are basically the same options available on the MSI P55-GD85; we could only see two options missing: “PCI Express amplitude control,” which increases the voltage used by the PCI Express clock signal, and “CPU amplitude control,” which increases the voltage used by the CPU base clock.

[nextpage title=”Main Specifications”]

The main specifications for the MSI P55A-GD65 are:

  • Socket: 1156
  • Chipset: Intel P55 Express
  • Super I/O: Fintek F71889
  • Parallel ATA: One ATA-133 port controlled by a JMicron JMB363 chip
  • Serial ATA: Six SATA-300 ports (black) controlled by the chipset (RAID 0, 1, 5 and 10), one SATA-300 port (blue) controlled by a JMicron JMB363 chip, and two SATA-600 ports (white) controlled by a Marvell 88SE9128 chip (RAID 0 and 1)
  • External SATA: One controlled by the JMicron JMB363 chip, shared with a USB 2.0 port
  • USB: 12 USB 2.0 ports (six soldered on the rear panel and six available through three headers on the motherboard) and two USB 3.0 ports (controlled by a NEC μPD720200 chip)
  • FireWire (IEEE 1394): Two ports controlled by a VIA VT6315 chip, one standard-sized soldered on the rear panel and one available through a header (the board doesn’t come with an I/O bracket to use this second port)
  • 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), with on-board coaxial and optical SPDIF outputs
  • On-board LAN: One Gigabit Ethernet port controlled by one Realtek RTL8111DL chip, connected to the system through a PCI Express x1 lane
  • Buzzer: No
  • Power supply required: EPS12V
  • Slots: Two PCI Express 2.0 x16 slots (working at x8 when two video cards are installed and with CrossFireX support), two PCI Express x1 slots, and two standard PCI slots
  • Memory: Four DDR3-DIMM sockets (up to 16 GB and up to DDR3-2133 through overclocking)
  • Number of CDs/DVDs provided: One
  • Programs included: Norton Internet Security 2010 (60-day trial), motherboard drivers, and utilities
  • Extra features: External clear CMOS button, Winki, DrMOS voltage regulator circuit, APS (Active Phase Switching), and OC Genie with “+” and “-” buttons
  • More Information: https://us.msi.com
  • Average Price in the US*: USD 170

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

[nextpage title=”Conclusions”]

The new MSI P55A-GD65 is basically an MSI P55-GD85 with one of the heatsinks of the voltage regulator circuit and its heatpipe, one of the Gigabit Ethernet ports, the voltage measuring points, and the support for SLI arrays removed. The layout and other features are absolutely the same. The good news is that the new GD65 is way cheaper than the GD85 (USD 170 vs. USD 230)! This is a terrific way to get a high-end motherboard and save a lot of money!

Of course if you really want to build a system with two video cards running under SLI, then you will have to pay more and get a motherboard with support for SLI.

Don’t forget that this motherboard has a PLX chip that prevents performance from dropping when you are running SATA-600 drives, USB 3.0 devices, and games at the same time. You may find cheaper P55-based motherboards around, but make sure you are comparing apples to apples. The P55A-GD65 motherboard is targeted to the enthusiast that wants the latest technologies running at the top of their performance.