The web has been alive with rumors of an upcoming update to AMD's 7-series chipsets that will somehow unlock the true overclocking potential of its Phenom processors. The rumor goes something like this: an updated South Bridge (SB750) will improve communication with Phenom, removing a previous bottleneck and improving the maximum overclock possible. We can't begin to explain the many issues with the various rumors, but we have to allow that somewhere buried deep in these rumors there is a morsel of truth.


The AMD 780G chipset, the South Bridge is the chip, er, at the south end of the image. USB, SATA and Audio all stem off of this chip.

The South Bridge of a chipset is typically responsible for I/O operations. The non-critical PCIe lanes come off of this chip, as do the SATA and USB ports. Audio codecs, networking interfaces and virtually all other components are also run off the South Bridge. The North Bridge on the other hand talks directly to the CPU and connects it to much higher speed elements of the system; things like graphics cards and main memory all stem from the typical North Bridge design. The point of this explanation being that if anything were going to improve overclocking performance, we would assume it would be the North Bridge, not the SB. However, AMD has taken a different approach from traditional chipset engineering as we will soon see.

We've been waiting for a motherboard with AMD's SB750 South Bridge ever since we started hearing these rumors, and we finally received one:

Foxconn sent us their new A79A-S motherboard that is part of their Digital Life series of products. This motherboard was not designed to be an extreme overclocker, but instead a feature rich platform that offers the capability to overclock when required. In testing to date, the board has actually gained a reputation of being an excellent overclocker along with a full featured BIOS. While the BIOS options are not as extensive as the top end 790FX products from ASUS or DFI, there are more than enough options to ensure successful overclocking for the vast majority of users. Foxconn is still developing the BIOS and we have sent our feedback on a few areas we would like to see improved, but overall, this board gets a recommendation from us.

We will take an additional look at the board during the official 790FX/SB750 launch activities next week but here are a few major features.  The A79A-S includes four x16 PCIe 2.0 slots (dual x16 or quad x8 electrical), one PCIe x1 and one PCI slots, six native SATA II ports featuring RAID 0, 1, 5, or 10 support, two dual e-SATA ports, dual Gigabit LAN ports, Realtek ALC888 HD audio featuring DTS Connect and Dolby Digital Live support, 12 USB 2.0 connections, dual IEEE-1394a connections, LED Debug display, and on/Off/CMOS buttons.

Let's take a look at how all of this works, at least what we know works.

How it Works, um, Kinda
POST A COMMENT

50 Comments

View All Comments

  • Xray1 - Friday, July 25, 2008 - link

    The possibility that it is all about cpu skew/timings does not contradict what I have said. Why do you need a 6 pin connection from a southbridge to the CPU to change these settings? You can do that with simple register programming (MSRs). That's just like what has been done in the past (especially in timing settings of the AthlonXP FSB).

    So for me the big secret 6pin connection still looks like a big hardware dongle to allow for AMDs overclocking tool to only work on AMD chipset mainboards. They wanted to make it 100% non-software accessible, so there would be no way of doing it on non-AMD chipset boards. That's all I said. And yes, it's also speculation. But as long as they keep it cloed source, it's a non-accessible feature for other chipset makers.
    Reply
  • ZootyGray - Friday, July 25, 2008 - link

    @ xray

    Agree. However we don't know. Are they going to keep it secret? Is it about competition? or proprietary? Is there more to it? Is there a hidden ?thing? in Phenom? Is there "black magic"? Has it all been a deliberate lag behind so that they can come roaring back to life and look like the greatest thing since the resurrection? Look what they did to nvidiot with the 48x0 release. And the new CEO wants to offer more performance. Lots going on here = wow! This has my attention, and I want facts.

    My point is that Anandtech is already barking up this same tree - they don't know - they have inquired - and they are reporting known facts - and that is the real food that we have come to eat. More will be revealed. Maybe the answer is the "don't dare mention"; but I doubt that. Maybe a lot of things. It's all exciting to me as AMD makes some noise.

    I watch and wait.
    Reply
  • eetnoyer - Thursday, July 24, 2008 - link

    "error of margin"?

    I think you meant confirmation, not conformation.
    Reply
  • The Preacher - Thursday, July 24, 2008 - link

    The clock speed reported by CPU need not tell the whole story. The new system might actually drop a clock cycle here and there and might not increase the CPU performance at all, despite the higher reported frequency. Reply
  • CyberHawk - Thursday, July 24, 2008 - link

    What is the product that we dare not mention its name? Mentioned twice in the article.

    If there is word about Overdrive Utility I guess that it is a new CPU on horizon.

    What do you think?
    Reply
  • nubie - Thursday, July 24, 2008 - link

    I don't think it is a new CPU, in "Final words" they seem to hint it is a new IGP with a lot more performance on tap.

    If they can storm the market with a 4850 for $200, I am sure that they can integrate something to run today's games at minimum settings on the motherboard and keep it under that price.
    Reply
  • luk1999 - Thursday, July 24, 2008 - link

    Could you test overclocking on this motherboard with some standard (non-Black Edition) Phenom? Reply
  • dvijaydev46 - Thursday, July 24, 2008 - link

    I wish you did at least a few benchmarks and published. I was very curious to see how a phenom performs at 3.5 GHz. Reply
  • MikeODanyurs - Thursday, July 24, 2008 - link

    My SB (supposedly SB700) has the same production week and only 2 digits and one letter difference on my Gigabyte GA-MA78GPM-DS2H motherboard. Anyone know if it's the letter or the 2 digit numbers that identify the SB750?
    http://i172.photobucket.com/albums/w35/IITravel/DS...">http://i172.photobucket.com/albums/w35/IITravel/DS...
    Reply
  • imaheadcase - Wednesday, July 23, 2008 - link

    Hardly can read pictures.. :P Reply

Log in

Don't have an account? Sign up now