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.
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Janooo - Thursday, August 7, 2008 - link
Gary,you could be right when you say:
"Curiously enough, AMD cited "competitive concerns" as a reason why it would not disclose exactly what's going on with this new overclocking feature. We still cannot help but wonder if it is because AMD is going a little too far in the sacrifices, it is willing to make in the quest for higher clock speeds."
Though, another reason could be that AMD found something nice that would give Intel even higher edge if they knew what AMD did.
ZootyGray - Thursday, August 7, 2008 - link
"reason could be that AMD found something nice"Agree. And this same statement was uttered when ACC appeared in the SB750 review.
I would like to know - WHAT is the sacrifice? The apparently unqualified statement seems to cast doubt and nasty slur, and really should be explained, methinks.
ET - Thursday, August 7, 2008 - link
First of all, I'd like to say well done on letting us know of the issues and not rushing out a review like other sites. (Though I must say that having access to both fast and in depth reviews is the best of both worlds, so I'm also glad these other sites exist.)One thing which wasn't clear to me was: "vertex and texture caches are fully associative instead of separate." "Fully associative" has a meaning when it comes to caches, yet I imagine that's not what it's about. Sounds from the sentence like the caches have been unified (as opposed to separate).
Since according to the text this is the only departure from the 2400's architecture, it'd be nice to clarify this point.
quanta - Wednesday, August 6, 2008 - link
It seems the 'new' Advanced Clock Calibration is based on something that already existed in SB700 but was undocumented.[1] Based on the speculation, ACC could be the clock skew feature used by some other motherboards.That aside, RAID5 is a definite welcome addition, but unless it includes XOR offload, it really isn't much of an improvement. BTW, it is inexcusable for not having Ethernet support these days.
The claim of adding 2 specific 1.1 ports for compatibility reasons is confusing. USB 2.0 ports are 1.1 already compatible, just using slower speeds.
HyperFlash is a poorly implemented idea, especially when production Flash SSDs already exceed the maximum bandwidth of HyperFlash modules anyway. It is better off to just wait for Flash SSDs to mature.
[1] http://www.overclockers.com/tips01369/">http://www.overclockers.com/tips01369/
Goty - Wednesday, August 6, 2008 - link
It's possible, but I find it odd that a notoriously anti-AMD site (at least recently) like overclockers.com did absolutely no testing to confirm this hypothesis.chucky2 - Wednesday, August 6, 2008 - link
...to please give us 690G results along with it, for the benchmarks and power consumption. This way, we can see if 780G and/or 790GX, or one of the other competing solutions, is a worthwhile upgrade for us. One of the Gigabyte 690G boards would be perfect...Chuck
ZootyGray - Thursday, August 7, 2008 - link
And which manufacturer's 780G mobo would run with a Phenom 9950BE ? Is that possible?I am wondering how far the 780G comparison can go; since several mobos were destroyed back in April or May anand testing. (search The Three Amigos or "pop goes the mosfet"). Did the various manufacturers make any changes to replace the cheap mosfets they were using? 780G is a great N/B chip but some older(?) boards need lower-power cpu's. Other newer boards? - not sure yet. Still awaiting the update on all that. Did I miss something?
chucky2 - Thursday, August 7, 2008 - link
So when the review comes out, use the maximum CPU that the 690G board supports, and carry that forward to the 780G and 790GX boards.Also it'd be nice to see the CPU comparison on like minimum CPU needed to play 1080p content.
Also, best price/performance CPU out, cheapest dual core out, and older AM2 CPU's such as the 3600+ X2.
Show us what we can expect when it's not a Phenom running in there, i.e. give us information users - both existing and new - would find helpful in the review.
Chuck
yyrkoon - Wednesday, August 6, 2008 - link
Lets just say that Stability is the main reason why I purchase what I purchase name brand wise. Motherboards, memory, and power supplies are my main concerns and probably will be for a long time to come.Anyways, performance numbers etc are always good to know also, but I think it would be good if you guys at anandtech could put some 'stability figures' in your motherboard results as well. "This board performed well ..." would not work for those of us who want to know actual figures either. So maybe you guys can include a page, half a page or something dedicated strictly to stability ?
One of the main reasons why I am asking for this is as an example, I have an AM2 opteron system, as well as Core 2 Duo system, and while I love my AM2 system, and it *is* 'very stable', it still can not touch the rock solid stability of the Intel system. I do not pretend to know why, but I would love to figure out why . . . Both system have a board made by the same manufacturer, have used the same memory, video card(same company made both the GPU, and motherboard chipsets - nVidia)power supply, and hard drives. Hell, the Intel system has even been overclocked for 6-7 months now : /
Going from the above I am left at guessing that it is either 1) a hardware implementation, or 2) drivers. User error *is* a possibility, but I would like to think that since I have been fixing / integrating systems since the early 90's . . . well that I at least know half of what I am doing. That said, this 'issue' is still over my head.
Calin - Thursday, August 7, 2008 - link
It could be hardware implementation, it could be something that could be solved by a microcode/BIOS update, or maybe not. Also, there might be a difference between individual components (as similar as they are in theory), difference in general quality between the two mainboards, difference in component quality on boards (either by design or by chance/bad capacitors). It might be in the drivers, or just in things written in the processor errata which are not taken into account by the software.