AMD 790GX - The Introduction

by Gary Key on August 6, 2008 12:00 PM EST

Prelude to a Review-

The AMD 780G chipset got us excited about integrated graphics platforms again after its release last March. You can imagine our surprise when AMD contacted us in April asking what we would like to see in the next IG chipset scheduled for release this year. Of course, we obliged AMD with our wish list that included everything from 8-channel LPCM audio over HDMI to HD 3650 or higher-level performance.

We also requested a new Southbridge with improved RAID performance along with RAID 5 capability. More importantly, we wanted a chipset that could run true CrossFire and bridge the gap between the budget IGP and enthusiast level markets.  In other words, we wanted a chipset that could serve the multimedia and small form factor audience in a uATX form factor or provide top-flight performance and features for the enthusiast in an ATX form factor.  You know, something like the NVIDIA 750a SLI product or Intel’s P45 only with an IG unit.

AMD listened intently and replied they had something that might just fit our requirements.  We were even more surprised to learn that it was arriving in late June under the 790GX moniker. Yes, we had to wait until early August but estimated release schedules in this industry have a tendency to be overly optimistic.  For those diehard AMD fans, the delay in the release of the 790GX has been frustrating. Mainly due to the fact that rumors swirling around the internet about the performance and capabilities of the 790GX have been a bit more optimistic than the release schedule.

Unfortunately, speaking of release schedules, we think later August would have been a better target after spending the last week testing our 790GX products. In fact, we ran across so many problems that our article today is a preview of the chipset capabilities. We will follow-up quickly (Editor- no more food or Guitar Hero until this is finished) with a full review of products from Gigabyte, ASUS, Biostar, and Foxconn.

The majority of our problems center on BIOS tuning and driver related maladies. After speaking extensively with the motherboard suppliers, we are certain the BIOS releases that arrived late last night or those coming today will address problems ranging from NB multipliers/HT Ref Clock change requests not accepted via BIOS or AOD to 8GB compatibility issues along with other minor performance hindrances like memory SPD settings not being read correctly when overclocking. PCI peripheral support with a couple of network and audio cards is also giving us trouble. Of course, BIOS tuning can take you only so far and the requirement for solid drivers is necessary.

The 8.521.1 driver set, aka Catalyst 8.8 beta, has significant performance optimizations for the 790GX plus full support for the new C1E power savings mode, PowerPlay, and deep sleep instructions for the SidePort memory, umm Performance cache. As is the case with beta drivers there are liable to be various features that might not work correctly. One important feature that failed to work properly for us was CrossFire operation with our HD 4850 or HD 4870 cards.

Other problems ranged from proper C1E implementations and S1/S3 resume issues to HDMI repeater/screen resolution setups with commercial BD playback software. AMD informed us late today that we should roll back to the 8.7 drivers for testing all items but C1E. Of course, this meant graphics, power management, and performance testing on our test platforms just got tossed out the window. It also meant a reduction in IG performance around 3%~5% and some quirky results with C1E and Cool-n-Quiet enabled.

 

On a side note, we still do not have the latest version of AOD working correctly with any of our 790GX and 9950BE combinations after a stellar appearance on the 790FX board we utilized in our SB750 preview. Actually, these problems are typical during the launch of a product. It just seemed that in our case the perfect storm brewed as it was nearly impossible to close out each benchmark session without running into a problem. We sailed through discreet graphic card testing with the beta drivers but were stymied with the inability to run CrossFire although Hybrid CrossFire worked fine.

Our power draw tests revealed three different sets of numbers, not an explainable difference due to a board’s components, but a 30W difference at idle with the same components and BIOS settings. RAID 5 testing resulted in several different sets of IOMeter results between the boards that we are still investigating. Problems even carried over to HDMI output through our receivers although it appears rolling back to the 8.7 drivers today cured those issues.

In our estimation, the BIOS and drivers needed some additional brewing time before the product release. While it may seem we are picking on AMD, this occurs with NVIDIA and Intel also. In fact, we could devote an entire page to our early experiences with G45. However, all this said, we did find the motherboards to be extremely stable in the normal course of testing with major applications that typical users will utilize. In addition, performance from the integrated graphics unit is simply superb considering AMD’s competition. We did not discover any show stopping problems that would prevent us from purchasing the product at this time. Just beware that a BIOS spin and updated driver release will be required to get the most out of the board’s additional features.

So let’s take a look at the chipset specifications of the 790GX chipset.

Heading up North...
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  • flipmode - Wednesday, August 6, 2008 - link

    What does underrated mean - that the Phenom hasn't been given the credit it is due? That's pretty much what it sounds like, and if that's the case then, isn't that ball in you guys' hands?
  • flipmode - Wednesday, August 6, 2008 - link

    gah! the quote button didn't work. my above post was supposed to start with this quote:

    "That brings us to what we see as the jewel of this product release, the SB750. It brings sorely needed overclocking headroom for the underrated Phenom processor"
  • Calin - Thursday, August 7, 2008 - link

    In this case, I think underrated means "rated at an inferior clock speed"
  • ZootyGray - Tuesday, August 12, 2008 - link

    it means it should be rated higher - but due to bias, market manipulation, and the gullibility of the general public - not to mention deliberate choice of test conditions designed to make look bad, unbeknownst to the gullible public, or deliberate intent to just emphasize all problems with little or no basis in fact - etc etc etc
    - and then delays and other self-important indulgences.

    Opposite to overrated. Result of market hype - a belief that the usual is superior when it has already gone flat.

    You know there are test reports all over the internet.
  • MikeODanyurs - Wednesday, August 6, 2008 - link

    What's the word on the AMD OverDrive 2.1.2 release?
  • Ephebus - Saturday, August 9, 2008 - link

    They can't even get a simple utility like AMD Power Monitor right, so I wouldn't expect much if I were you. AMD Power Monitor won't report the cores' clocks correctly anymore if the processor is overclocked - it shows the values as if it wasn't overclocked. The last version that worked OK with overclocked processors was version 1.0.2. There have been 3 releases since that version, and I've complained to AMD every time a new release would come out that the utility had stopped working correctly. Then finally some AMD guy said he tested it under Vista and it worked OK, but not under XP. Maybe they are not aware of all the people who won't touch Vista with a ten-foot pole? I was really disappointed by this kind of "support" and pretty much gave up on AMD. I've been buying inferior processors from them just to support the company (yes, I'm that idealist), but in my next upgrade I'll go Intel all the way.
  • ZootyGray - Tuesday, August 12, 2008 - link

    I don't believe anything you say. Your problem is not AMD's fault - is it?

    And do you suppose we should assume that an antitrust busted monopolist will babysit and care for us all?

    If so, you would probably put me in charge too - right? Careful.
  • Ephebus - Thursday, August 14, 2008 - link

    The utility is made by AMD for AMD processors, so yes, it is AMD's fault, fanboy.

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