[nextpage title=”Introduction”]

P55-GD85 (a.k.a. MS-7585) is the most high-end motherboard for socket LGA1156 processors from MSI, featuring USB 3.0 and SATA-600 ports plus a lot more goodies like points for measuring voltages from components, two Gigabit Ethernet chips and a PLX PCI Express switch chip to make sure your system will keep up its performance even when you try to use all of its features at the same time.

Since we’ve already took a look at MSI P55-GD80 – which is also based on P55 chipset but doesn’t come with USB 3.0 and SATA-600 ports – we will be able to spot the differences between these two motherboards, especially because GD85 isn’t a GD80 with the SATA-600 and USB 3.0 ports added: there are some other differences.

Like GD80, P55-GD85 uses a cooling solution based on an 8-mm heat-pipe that, according to MSI, is to date the thickest heatpipe used on a motherboard (usually motherboards use 5-mm heat-pipes), which translates in a better cooling capability. GD80 has an extra “arm” to the left on its cooling solution that was removed on GD85.

MSI P55-GD85 motherboardFigure 1: MSI P55-GD85 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 P55-GD85 has two PCI Express x16 slots using this configuration. GD80 from the same manufacturer has three PCI Express x16 slots, but this third slot works at x4. The portrayed motherboard also has two PCI Express x1 and two standard PCI slots, the same amount present on GD80.

This motherboard from MSI 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. On the MSI line-up P55-CD53 and P55-CD45 do not support SLI.

MSI P55-GD85 motherboardFigure 2: Slots.

Another small but very important detail is that MSI added a PLX PEX8608 PCI Express switch chip on this motherboard, which adds eight more PCI Express 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. P55-GD80 doesn’t have this chip, but this isn’t a problem, since this other board does not have SATA-600 and USB 3.0 ports.

MSI P55-GD85 motherboardFigure 3: PLX PEX8608 PCI Express switch chip.

[nextpage title=”Memory Support”]

Socket LGA1156 CPUs, like socket LGA1366 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 LGA1156 processors supports only DDR3 memories up to 1,333 MHz under dual-channel architecture, however MSI says P55-GD85 supports DDR3 memories up to 2133 MHz through overclocking. P55-GD85 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 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 black sockets. If you install them on the blue ones the computer won’t turn on.

MSI P55-GD85 motherboardFigure 4: Memory sockets. Install two or four modules for the best performance.

[nextpage title=”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.

MSI P55-GD85 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. And as you know by now, this motherboard has two SATA-600 ports (a.k.a. SATA 6 G), controlled by a Marvell 88SE9128 chip. These ports are white and support 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 SATA-300 ports controlled 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 as well.

MSI P55-GD85 motherboardFigure 5: ATA-133 port and SATA ports.

No floppy disk drive controller is present.

From the 14 USB 2.0 ports supported by the chipset, MSI P55-GD85 offers 12 of them, six soldered on the rear panel and six available through three motherboard headers. The motherboard comes with an I/O bracket containing two USB ports.

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 MSI P55-GD85 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 i
f 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 GD80), which provides professional-grade audio to this motherboard, with eight channels, 24-bit resolution, 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 6 this motherboard has fully independent analog outputs for all eight audio channels.

MSI P55-GD85 has two Gigabit Ethernet ports, controlled by two Realtek RTL8111DL chips, which are connected to the system using PCI Express x1 lanes, and thus not presenting any potential performance issues.

In Figure 6, you can see the motherboard rear panel with PS/2 mouse and keyboard connectors, clear CMOS button, coaxial and optical SPDIF outputs, FireWire port, six USB 2.0 ports, eSATA-300 port (shared with one of the USB 2.0 ports), two Gigabit Ethernet ports, two USB 3.0 ports (blue ones) and independent analog 7.1 audio outputs.

MSI P55-GD85 motherboardFigure 6: Motherboard rear panel.

[nextpage title=”Voltage Regulator”]

MSI P55-GD85 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 (Renesas R2J20602) 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.

This motherboard comes with a passive heatsink using a heatpipe on top of the “DrMOS” chips.

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 P55-GD85 motherboardFigure 7: Voltage regulator circuit with the heatsink.

MSI P55-GD85 motherboardFigure 8: Voltage regulator circuit without the heatsink.

Besides having a high-end voltage regulator circuit, P55-GD85 can disable phases from the voltage regulator circuit as needed in order to save energy, 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. MSI P55-GD80 has as advantage over GD85 having a display that indicates the number of active phases.

See how this motherboard uses an EPS12V connector for the CPU.[nextpage title=”Other Features”]

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 interesting overclocking-related hardware features that we will explore in the next page.

In Figure 9, you can see all the accessories that come with MSI P55-GD85. On the installation CD there is 60-day trial version from Norton Internet Security 2010.

MSI P55-GD85 motherboardFigure 9: Accessories.

[nextpage title=”Overclocking Options”]

MSI P55-GD85 like its sister P55-GD80 is clearly targeted to overclockers, featuring a 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 by 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. GD80 has as an advantage over GD85 having a two-digit display that shows the last two digits from the current base clock value.

In Figure 10, you can see all buttons available on this motherboard: OC Genie, the “+” and “-” buttons, reset and power.

MSI P55-GD85 motherboardFigure 10: Buttons.

MSI P55-GD85 features voltage monitoring points, where the extreme overclocker can install a multimeter to manually monitor the CPU, memory and chipset voltages.

MSI P55-GD85 motherboardFigure 11: Voltage monitoring probes.

GD80 has a feature that was also removed on GD85: overvoltage switches to prevent you from increasing voltages above a dangerous level where you could burn components.

Let’s see the overclocking options available on MSI P55-GD85 setup.

[nextpage title=”Overclocking Options (Cont’d)”]

The main options we could see 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 differential amplitude (“CPU amplitude control
    ”): 700 mV to 1 V in 100 mV increments.
  • PCI Express amplitude control: 700 mV to 1 V in 100 mV 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 (PCH) voltage: 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 memory module).

Memory timings can also be tweaked.

MSI P55-GD85 motherboardFigure 12: Overclocking menu.

MSI P55-GD85 motherboardFigure 13: Overclocking menu (Cont’d).

MSI P55-GD85 motherboardFigure 14: Overclocking menu (Cont’d).

MSI P55-GD85 motherboardFigure 15: Memory timing options.

[nextpage title=”Main Specifications”]

MSI P55-GD85 motherboard main features 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: Seven SATA-300 ports, six controlled by the chipset (RAID 0, 1, 5 and 10) and one controlled by a JMicron JMB363 chip. Two SATA-600 ports controlled by a Marvell 88SE9128 chip (RAID 0 and 1).
  • External SATA: One controlled by the JMicron JMB363 chip, port shared with a USB 2.0 port.
  • USB: 12 USB 2.0 ports, six soldered on the motherboard and six available through three headers on the motherboard. The motherboard comes with one I/O bracket containing two USB ports. 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). On-board coaxial and optical SPDIF outputs.
  • On-board LAN: Two Gigabit Ethernet ports controlled by two RTL8111DL chips, each one 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), two PCI Express x1 slots and two standard PCI slots.
  • Memory: Four DDR3-DIMM sockets (up to 16 GB 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), OC Genie with “+” and “-“ buttons and probes for monitoring CPU, memory and chipset voltages with a multimeter.
  • More Information: https://www.msicomputer.com
  • Average price in the US*: USD 230.00

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

[nextpage title=”Conclusions”]

MSI P55-GD85 is an outstanding high-end motherboard for the socket LGA1156 platform, especially because it costs only USD 30 more than MSI P55-GD80, which is a similar motherboard from MSI without SATA-600 and USB 3.0 ports. One of the main advantages of P55-GD85 is the presence of a PLX PCI Express switch chip, which will allow you to achieve the maximum performance from your system even when using two SATA-600 drives, two USB 3.0 devices and two video cards at the same time. If you are looking for a fully loaded high-end motherboard for your socket LGA1156 CPU, this motherboard is worth serious consideration. We simply can’t find any single flaw on this product.

Of course it is not the cheapest motherboard around, but it provides a terrific cost/benefit ratio for its intended audience, especially when you think that competing products like ASUS P7P55D Premium, which has SATA-600 ports but not USB 3.0, are more expensive.

It is important to keep in mind that P55-GD80 has some features that were removed on GD85, like overvoltage protection switches, display to show the current CPU base clock, display to show the current number of active phases on the voltage regulator circuit and the third PCI Express x16 slot.