NVIDIA Hybrid SLI and nForce 700a Chipsets

Introduction to Hybrid SLI

NVIDIA is the sort of company that can and will capitalize on opportunities quickly, whether it be market or product related, or something as simple as logistics.  As such, in traditional fashion, with the huge insurgence of press and media swooping down on the never-ending sensory overload that is the city of Las Vegas and the CES show, NVIDIA took the opportunity to arrange an editor's day just prior to the opening day of CES.  With a venue like this and a captive audience to boot it's a proverbial no-brainer and so we convened at the New York-New York hotel and casino for an update from virtually every product group at NVIDIA.

If you've been spending some time here at HotHardware, you'll recall our coverage of AMD's Hybrid CrossFire technology for the mainstream desktop segment and the benefits of combining on-board IGP graphics with a discrete card.  Of course NVIDIA also has an answer for this, as you'd expect and we'll step through the salient points and highlights of Hybrid SLI for you in the pages ahead.

In addition, the company is also announcing the new nForce 700a series of chipsets for the AMD platform.  It too brings with it an offering of new features and functionality that NVIDIA is disclosing today and we learned a bit about some of NVIDIA's patented PCI Express Switching IP in the process as well.

Like AMD's Hybrid CrossFire, NVIDIA's Hybrid SLI technology gives users the ability to pair an IGP, or mGPU (motherboard GPU), with a discreet graphics card, or cards, for two new modes of operation.  NVIDIA calls these new modes Hybrid Power and GeForce Boost.

GeForce Boost does what its name suggests.  By coupling the motherboard's integrated GPU with a discreet graphics card, the 3D rendering workload is shared between the two GPUs for a boost in performance.  Currently, GeForce Boost is only supported by GeForce 8400 GS and 8500 GT discreet cards, as for the IGP, only the next-gen nForce 700a series of chipsets due to arrive this quarter will be supported initially.  New IGPs for the Intel platform that support Hybrid SLI are slated to arrive in Q2.

Hybrid Power mode is also fairly self explanatory.  With a monitor connected to the mGPU, the discreet graphics card can be completely shut down to reduce power consumption when no in use.  A side effect of the reduced power consumption will also be reduced heat and potentially less noise output from the system.  The discreet card is shutdown (or enabled) using the SMBUS connection inherent to the PCI Express graphics slots.  We should also note, that Hybrid SLI is supported by both PCI Express Gen 1 and Gen2.

NVIDIA's Hybrid SLI technology is controlled by system status and the Window Vista Power Plan.  Hybrid Power, for example, is enabled when the system reaches an idle state to reduce power consumption.  We spoke with NVIDIA and asked if an auto-switching system based on applications or workload for GeForce Boost and Hybrid Power was in the works, and company representatives explained that they would like to enable this type of functionality, but that it wouldn't be ready upon initial release.

At first, a new control panel icon in the system tray will give user's the ability to configure Hybrid SLI for other modes of operation.  Because a Hybrid SLI system will have multiple GPUs installed, it's also possible to run multiple displays.  The new control panel icon and final set of tools will be available in an upcoming driver release.

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