For several years NVIDIA denied its SLI technology to be used in conjunction with chipsets of competitors. These were almost always political reasons, not technical ones as frequent driver hacks showed. This usually meant that if you wanted to use SLI on AMD platform, you needed a chipset from NVIDIA. On the Intel platform, SLI support developed into a licensing war between Intel and NVIDIA, as the company was barred from producing chipsets for newer Core "i" series of processors. Even though Intel paid a high price, NVIDIA opened SLI to select Intel chipsets in two ways: via often criticized NF200 bridge chip (thermal issues) or simple licensing agreement.
Last time we saw SLI heavily advertised for the AMD gaming platform: 2006 and the nForce 590 chipset
Since AMDs CPUs weren’t dominating in performance and the company’s mindshare among gamers dropped, the platform wasn’t that interesting for NVIDIA. Things are changing, though. With upcoming CPU architecture codenamed Bulldozer, the SLI technology on AMD platforms just might become interesting again for gamers. In any case, NVIDIA withrew from the chipset business for AMD platforms back in 2009, so they need to take a different approach if they want to support SLI on the AMD platform. If slides revealed from our colleages at VR-Zone are to believe, they simply do so by flipping the switch in their driver to support SLI on the upcoming 990FX and 990X chipsets from AMD.
Leaked VR-Zone slide from nVidia, detailing the return of SLI on AMD platform
According to the slide, NVIDIA licenses SLI for use with the 990FX and 990X chipsets under similiar terms as for Intel’s P67 chipset. This basically means that mainboard vendors need to pay a license fee to NVIDIA – $5 per every motherboard. Both 2-Way SLI and 3-Way SLI are supported on the 990FX, while the 990X will only support 2-Way SLI (limitation due to available PCI Express lanes). Interesting note is that the use of the nForce 200 companion chip is not supported. Also, according to the current information, AMDs previous generation 7-series and 8-series chipsets will not get SLI-support retroactively.
AMDs 9-series chipsets are said to be launched in the current quarter, meaning only few weeks from now. It’s highly likely that the launch will take place at the same time the AMD FX CPUs based on the Bulldozer architecture will be introduced. According to information leaked by AMDZone last fall, the 9-series chipsets will be slightly updated variants of the 8-series chips. Most of the features remain the same, though some of the chipsets get a IOMMU (I/O Memory Management Unit). This part is essential for I/O virtualization. So basically a 990FX chipset is a 890FX with an IOMMU. The same goes for the 990X and 970 chipsets, you get the picture. This also brings the possibility that AMD will return focus on workstation market with the single socket platform, which the company abandoned due to competition from Intel – as stated by Leslie Sobon, Corporate VP.
The 980 chipset will feature an outdated DX10.1 IGP and according to the slides doesn’t even feature an IOMMU, so it’s basically a rebranded 880. Though in the IGP space, AMD will offer a much better platform with the Llano APU anyway, which offers a DX11 GPU on the same die as the CPU. The southbridges again look a lot like rebrands of the current SB 8xx offerings. The featuresets look much the same and USB 3.0 is glaringly absent. So AMD doesn’t really do any better than Intel on their high-end platform. However the upcoming Llano chipsets A75 (Desktop) and M70 (Notebook) will feature USB 3.0 as the USB-IF compliance database revealed.