Closer Look: M4A88TD-V EVO/USB3

The M4A88TD-V EVO/USB3 motherboard doesn't look like a budget board. The only tell-tale clue comes from the abundance of PCI slots. High end boards tend to feature more PCI Express slots, to accommodate the latest add-in boards. Budget boards tend to have more PCI slots, which allow consumers to continue using their old peripherals when they upgrade. There are only a few ASUS motherboards based on this combination of an 880G Northbridge and a SB850 Southbridge. More than half of them are µATX boards, but don't let that put you off. This pairing of modern components provides excellent performance and the latest features at low cost. Plus, its full-sized ATX form factor means that it has more of those PCI slots to accept your existing hardware.

Perhaps the most significant feature of the M4A88TD-V EVO/USB3 is the SB850 Southbridge, which supports six native SATA 6Gb/s ports and USB 3.0 with full PCI Express 2.0 connectivity. The Intel P55/H55 chipset has to jump through hoops to support the latest high-speed peripheral interfaces with anything close to full bandwidth, but the SB850 does it in stride. While a USB3 interface is not integrated into the Southbridge, there are two "extra" PCI Express 2.0 interfaces there, which allows easy connection to the most common USB3 support chips. It is also possible to connect the USB 3.0 support chips up to the 880G Northbridge, as it also has some "spare" PCI-Express 2.0 lanes available. Latency is likely to be lower with this NB connection, so look to see how each motherboard vendor implements the USB 3.0 connection. All this is accomplished at a much lower cost than any Intel-based solution currently available. While Intel is ahead in the inevitable push to integrate NB and SB functions, their current chipset leaves too many interfaces behind; interfaces left to be performed by additional support chips.

The AMD 880G Northbridge incorporates a Radeon HD 4250 integrated graphics processor in addition to the normal functions of handling the PCI Express 2.0 lanes for discrete graphics and providing a bridge between the CPU and the Southbridge. The data link to the CPU is accomplished by HyperTransport 3.0, with a transaction rate of 5.2GT/s (gigatransfers per second). The South-side data link to the SB850 has been upgraded to 2 GB/s with the use of A-Link Express III, which trades the old four lanes of PCI EXPRESS 1.0 for the same number of PCI EXPRESS 2.0, thereby doubling the capacity of the link. This takes care of any potential bandwidth issues with transferring SATA 6Gb/s data. Plus, since USB 3.0 connects directly into the Northbridge, the SATA data doesn't have to compete with it for bandwidth.

The Radeon HD 4250 is still based on the Radeon HD 4200, first found in the 785G chipset launched in August of 2009. The only difference is the base clock rate of the GPU, which has been bumped up from 500MHz to 560 MHZ. The HD 4290 in the 890GX is specified at a base clock of 700 MHZ, but ASUS includes their GPU Boost feature in the BIOS of the M4A88TD-V EVO/USB3, so if you need to crank up your integrated graphics, have at it! They are all built on the same graphics core, the RS880 with 205 million transistors and 40 stream processors. At the mid-market price point, most everyone has implemented the 128MB of sideport memory, which is directly addressed by the graphics core, unlike the remaining system memory. Low end boards generally do without the benefit of the dedicated sideport memory.

In common with most IGPs, which are called on to drive the majority of PC-based home theater setups, the HD 4250 has no shortage of support for video standards. HDMI 1.3, UVD2 / AVIVO support, DirectX 10.1, and hardware MPEG-2/VC-1/H.264 decoding are all catered for, gratis. The Radeon HD 4250 is supposed to support Hybrid CrossfireX with the Radeon HD 5450. This is the first time the HD 4xxx series of IGPs has supported a modern GPU in Hybrid CrossFireX. I didn't have any success with it, using Catalyst Control Center 10.6. My HD 5450 card is an engineering sample, and may need a BIOS update. Or, maybe the base driver needs to be the IGP driver from ATI. The manual was VERY generic in its instructions.

ASUS uses an 8+2 PWM design for the M4A88TD-V EVO/USB3, as it does on almost every modern AM3-socketed motherboard they produce. Even the ASUS Crosshair IV Formula, which costs almost double the price ($ 229.99), uses the same basic topology. Someday, I'll figure out how it is that Intel CPUs benefit from 16+2 phases of PWM power, and AMD chips don't....some people blame it on a limitation with the AM2 architecture. ASUS makes the case that their board offers "True" 8+2 phase power, and it's true, all right. The PWM controller chips, which is where the PWM phases are first generated, output 8 distinct, separate phases that get delivered to eight full sets of drivers and power MOSFETs. Unfortunately, there are some other boards that only have a 4-phase PWM controller, and then double the number of filter chokes and capacitors, to make it appear that twice that number of phases is present. Some use a "phase splitter" to create the additional phases, but the PWM controller can only control the downstream devices in groups of two, limiting the power quality vs. power efficiency balance. All of the power MOSFETS and drivers are covered by a long, thin heatsink, next to the row of ferrite chokes. It's physically held in place with the typical spring-loaded plastic lock pin, and contacts the power transistors via thermal tape.

The rear I/O panel has 6 USB ports (the two blue ports are USB 3.0), one PS/2 connector for Keyboard, an optical S/PDIF port, HDMI, VGA and DVI ports, an IEEE 1394 Firewire port, an E-SATA port, a gigabit Ethernet port, and the regular 8-channel audio ports. Nothing out of the ordinary here, except the blue USB 3.0 ports, shown by balloon number 11 above.

At the rear edge of the board, the five SATA connectors face up, not out to the side. This is not always a negative, as some PC cases don't have enough room around the back edge of the motherboard to allow for SATA cables sticking out. In some instances, the 90 degree ports provide a cleaner install, but the odds of a budget case having the necessary room in this area are about 50/50. ASUS played it safe here, and I can't blame them. The same goes for the PATA connector, although I imagine most people would use the PATA interface for their older optical drive and would like it to be located closer to the top of the board, where most people place their ODD. I could be wrong, as many people have one or two old PATA HDDs lying around, and a new SATA DVD writer is generally less than $30.

The card slot layout is pretty standard, and given the fact that it really doesn't need to support SLI or CrossFireX, the only given is that you will lose access to one of the three standard PCI slots when you install a 2-slot graphics card. Not a great loss, as you still have access to two regular PCI slots, one PCI Express x4 slot, and one PCI Express x1 slot. The upper, dark blue connector is the one wired for x16, and the only place you would want to install a high-end graphics card. I must admit to being confused when I looked at the back of the motherboard, as the x4 slot is actually soldered in with a full 16 lanes worth of connector pins, despite the fact that it only supports four of those 16 lanes. The board is also silk-screened with an x16 designator, even though it is only an x16 in the mechanical sense.

Let's take an even closer look at some of the unique features on this motherboard...

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