|ASRock AOD790GX/128M AM2+ Motherboard|
|Reviews - Featured Reviews: Motherboards|
|Written by Bruce Normann - Edited by Olin Coles|
|Tuesday, 10 March 2009|
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AMD 790GX Details
The AMD 700-series chipset covers a lot of bases; as one leg of AMD's new DragonTM platform, it has a pretty strong team backing it up. The fusion of the AMD PhenomTM II processor, ATI RadeonTM HD 4800 series graphics, AMD 7-series chipsets, and AMD software should yield seamless integration between all the major PC subsystems and the highest possible level of performance at the lowest cost. If that sounds like a tall order, it is, and the success of companies like NVIDIA put a wrinkle in that perfect picture.
The 700-series integrated chipset solution buys you the following capabilities and features:
It's a very strong platform, and gives Intel and NVIDIA plenty of competition as the basis for high-definition gaming, video processing and home entertainment PCs. AMD claims that it is "... the only company in the world that can deliver all the essential technologies for an amazing gaming experience and breakthrough video processing speeds with our world-class processors, graphics, and chipsets." True enough... The AMD 700-series chipsets are produced by the giant Taiwanese semiconductor foundry TSMC, and in the case of the 790GX, the latest chip in the series, uses the latest 55nM fabrication process. 55nM was a direct, linear die shrink from the 65nM process, so AMD didn't have to do any architecture or device redesign for the 790GX. They just took advantage of their partner's technology progress, when TSMC rolled out the improved process in May 2007. I'm sure this is exactly the sort of thing AMD hopes to do more of in the future, now that they've sold off all their production wafer fabs to a third party.
The AMD 790FX Northbridge offers 42 available PCI-E lanes, which explains some of the monster motherboards featuring 4 PCI-E 16X expansion slots. If you use all four, they have to throttle back to 8X bandwidth, but when you can pick up four ATI 4830 cards for about $300, the possibilities look pretty interesting. The ASRock AOD790GX/128M uses the newer 790GX Northbridge, which supports 26 PCI-E 2.0 lanes, limiting it to 8X bandwidth in dual Crossfire mode. You might ask, "Can I run 3-8X cards; that only consumes 24 lanes of the 26?" Unfortunately, the answer is no, since four of the 26 lanes are consumed by the chipset interconnects, leaving only 22 lanes available for onboard peripherals and expansion slots.
The ASRock AOD790GX/128M has an ATI Radeon 3300 integrated graphics processor, 128MB of sideport memory hooked directly to the NB, and can run in Hybrid CrossfireX mode with Radeon 3400 series video cards, as long as you are running Vista. This is an excellent component set for general office use or a HTPC, however it's largely irrelevant to enthusiasts or gaming users. BTW, the sideport memory is being called a "Performance Cache" by some vendors; don't be fooled, its sole function is to act as video memory for the IGP. It doesn't interface with the rest of the Northbridge, nor offer any performance benefit unless you are using the built-in video capability, where it does do an excellent job of speeding up the integrated graphics.
The SB750 Southbridge caused quite a stir when it was introduced in 2008, as it introduced Advanced Clock Calibration (ACC) to the world, a feature that is now built in to the Phenom II class of CPUs. How that functionality ended up in a Southbridge is anybody's guess, the whole story seems shrouded in secrecy. But, if you've got a Phenom CPU that needs a new mobo, pick one that has a SB750 Southbridge if you want to overclock it. Additionally, if you want to take advantage of the ACC feature within AMD OverDriveTM, you also need the SB750. In case you're wondering, that's what the "AOD" in the product name, AOD790GX/128M refers to.
Surrounding the processor socket there are the usual power supply components: switching transistors, capacitors and chokes. ASRock offers its own version of power-saving design, calling it Intelligent Energy Saver. Like most power saving schemes, it reduces clock speed and voltage in tandem. They've also focused on the design of the voltage regulators and are claiming a 16% increase in efficiency. This is a smart approach, because even though the components draw less current when you feed them less voltage, the "extra" voltage has to be dissipated by the voltage regulator; the power supply is still putting out 3.3, 5, and 12 volts.
Going from left to right on the I/O panel, there is not an overabundance of connections available, but a reasonable set, at least. PS/2 keyboard and mouse ports are still supplied, which is handy when starting up a new system, if the MB has trouble connecting to a USB KB and mouse. A total of six High-Speed USB 2.0 ports populate the I/O panel, with another four available on two motherboard headers, for connection to the case I/O panel.
There is one IEEE-1394 Firewire ports on the I/O panel; the larger, 6-pin version which is commonly used on larger, stationary devices, such as 3.5" external HDDs. There is also an additional motherboard header available to connect to an IEEE-1394 port on your computer case I/O panel, if one is supported. One Ethernet LAN connections is supplied, with activity and link speed indicators at the corner of the RJ-45 port. ASRock includes the high-definition Realtek ALC890 audio controller on the AOD790GX/128M with support for Full HD 1080p Blu-ray (BD) / HD-DVD playback. S/PDIF digital audio OUT is available on the motherboard, and can be used for internal connection to a video card for full HDMI compatibility.
The external eSATA connector on the rear I/O panel is not hardwired to the board; it requires a cable connection, jumpered from the sixth SATA connector near the bottom of the board, which is specifically designated to support this function. The first five SATA connectors only support regular SATA II connections; the sixth can function as a normal SATA II port, or as the pass-thru for the external eSATA port. ASRock conveniently color coded the two SATA sockets that need to be connected differently from the other sockets; it's the brown one.
In the next section, component layout is examined, an area that is all too often an unexpected weakness for some motherboards.