790GX and SB750 explored and reviewed

Motherboards/AMD AM2+ by massman @ 2008-10-02

The 790GX chipset has been released a while ago and motherboards equiped with this chipset and the new southbridge chipset SB750 are now widely available in the local hardware shops. Madshrimps has had its sample, sent by AMD, on the testbench a while now and today we have a look at the new technology, including a better IGP and supposedly better overclocking.

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Key features of 790GX and SB750 chipset

Key features of the 790GX and SB750
Before writing this review, we had a quick look at the presentation files AMD has given us after the conference call regarding the release of the 790GX and SB750 chipset. From those presentation files, we withheld the most important pointers of these new chipsets.

Madshrimps (c)

User groups

For AMD, there are basicly three different categories of pc users: the performance user, the multimedia user and the mainstream user. The first group is that group that wants the absolute maximum performance to play games at high resolutions, want complete motherboards with all the features and extra's you can imagine and, most importantly, want to finetune their configuration as fast as possible. The multimedia user aims at, obviously, movie and music playback quality, fast storage, a lot of cores to encode and decode videos and keep an eye on the power efficiency. The third and last group, the mainstream user, wants performance for the bukc quality: a built-in IGP, tweakable configuration and updateable system parts if the system becomes too slow in the future.

Now, for each of these groups, AMD has designed a number of different features and tools.

Overclocking and tweaking your system

The new SB750 chipset has a better communication with the processor as the two communicate directly with each other, providing a more stable overclock. At least, that's how AMD sees it and explains it to it's costumers. The new technology is called 'Advanced Clock Calibration' and basicly fixes the broken signals between the processor and southbridge. What it exactly does is quite technical and would require a few pages to explain, but you can compare it to what Intel introduced with the GTL+ voltage levels. By elevating or decreasing the voltage of the GTL+ level, your system needs less Vcore to obtain the same overclock and, thus, is the overclock more stable after adjusting the GTL level. Changing the ACC setup can make your cores run more stable. More on this in the overclocking section of this review.

Madshrimps (c)

The second development is a tuning tool named AMD OverDrive which is a combination of SetFSB and A64tweaker/Memset, but better and more elaborate. You can tweak nearly every setting and voltage of your Phenom-based setup and, to be honest, it works quite well! There are built-in stress tests and there's an option to let the system decide what's the maximum stable overclock. Basicly, the HT link (~FSB in Intel terms) increases, making the system more and more unstable and when the system finally crashes and reboots, the program remembers the last stable setting and applies that setting at the next boot.

Upgrading from IGP to Crossfire-X

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The 790GX features a new, better and faster type of integrated graphics processor: the HD 3300. Being completely silent, this little chip can produce DirectX10 3D graphics, be it at a lower level than the modern videocards. However, as AMD says, this is mainstream-minded, in other words for those who don't have the need to play the newest games at resolutions exceeding 1280x1024. This is only the first step of the upgrade path AMD has laid out for you; the next step is: Hybrid graphics. Basicly, you have your IGP and add a low-end videocard to your system and the 3D performance will be higher than if you would only use the low-end videocard, because the IGP helps to create the images. Crossfire, but at a much lower level. The last step in the upgrading path is the Crossfire-X, which is the possibility to stack up multiple high-end videocards in your system. The more videocards, the more performance, the higher the resolution, the higher the AA/AF ... the better the gaming experience! Amd allowes a maximum of four cores to co-operate, although some sources say that Crossfire would have no problem working with even more cores. Too bad the drivers don't allow this hypothesis to be tested.

More on the IGP, you can find in the 'HD 3300' section of this article.

More performance, less power: power efficiency

The only proper way to explain what AMD claims to have innovated on the power efficiency is by showing you what AMD published in the presentation files.

Madshrimps (c)

To be honest, I'm quite sceptical about all this power efficiency ramblings. Okay, I may not be the heavy environmentalist who cares about every green leaf and tries to end the suffocating of the this (beautiful) planet, but I do want to save energy to pay as less on electrical bills as possible. The new innovations that have been introduced on Intel platforms as well, claim to save you a lot of power just by deactivating certain parts of the motherboard or by making those parts need less voltage. But ... In my experience it's possible to say a lot more money by overclocking and underclocking your system. If your system works at a comforting speed, go into the bios and decrease the voltage. Do you want higher frequencies for games? Overclock only one core! Tests on the Intel platforms have shown, by the way, that these 'green inventions' are not that energy-saving as the advertisements would let us believe. But then again ... they are advertisments.

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