ADFS 2011 Wrapup & AMD Lynx Platform Tests

Company: AMD
Author: James Prior
Editor: Charles Oliver
Date: July 18th, 2011

Llano Performance Testing: A8-3850 and Gigabyte A75M-UD2H mainboard

The good folks at AMD supplied us with an A8-3850 and Gigabyte A75M-UD2H mainboard. This is the top end desktop APU, with 2.9GHz quad core CPU and 600MHz 400 Radeon Core GPU. The mainboard is a microATX design with four memory slots, two PCI-Express Graphics slots (one x16, one x4), a single PCI-E x1 and a PCI v2.3 32-bit slot.

The A75M-UD2H is equipped with the A75 Fusion controller hub (FCH), which provides four USB 3.0 ports, eight USB 2.0 ports, six SATA-3 6Gbps ports, and four PCI-Express lanes. Additionally, Gigabyte added two Firewire/IEEE-1394 ports from a VIA VT6308 chip, and several legacy ports using an iTE IT8720 chip. This provides a serial port header, parallel port header, and PS/2 keyboard/mouse connections. There are two dual USB 2.0 port headers, an IEEE1394 header, and dual USB 3.0 front panel header. Rear-mounted brackets for all these headers are available as optional extras from Gigabyte - disappointingly none are included in the box.

Audio is provided by Realtek ALC889, which offers ten DAC channels to support 7.1 playback with independent stereo through front panel outputs - multiple streaming. The chip sports a 108dB SNR for playback, and 104dB SNR for recording. S/PDIF optical out is provided at the rear, and internally there is a two-pin header. A Dolby Home Theater function controlled through the Realtek control panel software allows virtual surround for audio sources less than the number of channels you have connected, i.e. stereo to 7.1, 2.1 to 5.1 etc. A Realtek 8111E chip provides gigabit Ethernet connectivity. There are two fan headers, one 4-pin for CPU fan and one 3-pin for system fan, which can be automatically controlled by temperature. The board has a trusted platform header for plugging in a TPM module, and dual BIOS.

The first PCI-Express Graphics slot is v2.0 with x16 lanes, for full bandwidth performance and is connected directly to the APU. The second slot is also PCI-E v2.0 and physically x16 but electrically x4. The two slots are triple spaced, with the PCI-E x1 and PCI bus in between them. The second slot should be thought of more as a general expansion port than for running dual graphics cards, although it has enough bandwidth for current mainstream cards, it will likely bottleneck enthusiast and performance cards. The PCI-E x16 slot form factor means that any host bus adapters or RAID cards, audio cards, tuners, SSDs/RAMDISKs on a stick that you might want to use will fit, and for those applications PCI-E 2.0 x4 lanes in a lot of bandwidth. It's a a per board design decision if the 16 lanes from the APU are dynamically split between two (or more) PEG slots. Gigabyte claims dual discrete multi-GPU support on the Gigabyte A75M-UD2H, but Crossfire wouldn't engage for us using two Radeon HD 6670s.

The board requires a 24-pin and 4-pin ATX power inputs; no need for EPS12v here. Gigabyte use a 4+1 PWM phase design, meaning four power phases for the APU and 1 for memory. The VRMs are cooled using an aluminum heatspreader, sprung mounted and not particularly strongly fixed in place. The Fusion Controller Hub is cooled by another aluminum heatspreader, low profile and screw mounted in place.

The FM1 socket has 905 holes for the pins on the APU, and is physically a little smaller than AM3. The heatsink mounting mechanism is the same as AM2/AM3, existing coolers compatible with those sockets should work fine.

The use of 'solid' 50,000 hour Japanese capacitors is pervasive, and the layout is fair. The triple spaced PCI-E x16 size slots means that the lower slot blocks the SATA ports and front panel headers when using a double-height card. The Front panel audio headers couldn't get any further way from the front of a case, either. There is only a single system fan header, meaning you'll need 4-pin molex to 3-pin fan header adapters or a fan controller if you have more than one chassis fan. This board is clearly designed for use in HTPC or SFF cases.

The DVI port can be enabled in Dual-Link mode for supporting 2560x1600 resolution displays, via a BIOS option. This option also disables the other outputs. The rear USB ports are individually fused, meaning if an overload current condition occurs and blows the safety fuse, on that port will be disabled. The ports are also higher power draw capable than traditional USB ports, for use with charging smart phones and tablets. This can be done even when the system is off, using the red colored ports.

The four DDR3 memory DIMM sockets are spaced to allow RAM with heatspreaders. The board supports the official speeds of DDR3-1333, 1600 and 1866 via standard multipliers in the BIOS. All Gigabyte Ultra Durable (the UD part of A75M-UD2H) mainboards support upto DDR3-2400 speeds, via overclocking. AMD's A75 FCH provides four USB 3.0 ports and six SATA 3.0 ports. Two of the USB 3.0 ports and a single eSATA port are present on the rear of the board, with the remaining two USB 3.0 ports available via header (not included).