680i SLI is too expensive? Asus as the solution : P5N32-E SLI PLUS

[renethx]

So summarizing Tom's information from NVIDIA and Naughtyboy's thought,

SPP (System Platform Processor, Northbridge)

Apparently there are four kinds of C55:

• C55 for 650i Ultra
  
  • FSB 1066/800MTps
  • DDR2-800/667/533, up to 32GB
  • 18 PCI Express lanes with links 16,1,1
• C55 for 650i SLI (printed "NF650I-SLI-N-xx" or "C55-SLIX8N-xx" on the chipset surface)
  
  • FSB 1066/800MTps
  • DDR2-800/667/533, up to 32GB
  • 18 PCI Express lanes with links 16,1,1 or 8,8,1,1
• C55 for 680i SLI "Lite" (printed "C55-SLIX8N-xx" on the chipset surface)
  
  • FSB 1333/1066/800MTps
  • DDR2-1200*/800/667/533 (* for SLI-ready memory with EPP), ECC or Non-ECC, up to 32GB
  • 18 PCI Express lanes with links 16,1,1
• C55 for 680i SLI (printed "NF680I-SLI-N-xx" or "C55-SLIX16N-xx" on the chipset surface)
  
  • FSB 1333/1066/800MTps
  • DDR2-1200*/800/667/533 (* for SLI-ready memory with EPP), ECC or Non-ECC, up to 32GB
  • 26 PCI Express lanes with links 16,8,1,1

Actually there are only two kinds of C55, however:

• C55
  
  • FSB 1333/1066/800MTps
  • DDR2-1200*/800/667/533 (* for SLI-ready memory with EPP), ECC or Non-ECC, up to 32GB
  • 18 PCI Express lanes with links 16,1,1 or 8,8,1,1
• C55XE
  
  • FSB 1333/1066/800MTps
  • DDR2-1200*/800/667/533 (* for SLI-ready memory with EPP), ECC or Non-ECC, up to 32GB
  • 26 PCI Express lanes with links 16,8,1,1

The only difference between C55 and C55XE is that C55XE has an extra x8 PCIe link (for a third PEG port which will be used by a future nVIDIA solutions for particle). C55 for 650i Ultra/650i SLI/680i SLI "Lite" are all the same as the C55 vanilla (identified as 650i SLI SPP by CPU-Z) with some functions disabled at the motherboard/BIOS level. C55 for 680i is the C55XE (identified as 680i SLI SPP or erroneously C60 by CPU-Z; C60 is the canceled IGP solution for Intel, cf. the INQUIRER).

MCP (Media and Communications Processor, Southbridge)

There are two MCPs for nForce 600i Series:

• MCP51 (a.k.a. nForce 430, printed "MCP51-xx" or "NF-430-N-xx" on the chipset surface)
  
  • No PCI Express lane
  • 2 x PATA, 4 x SATA at 3.0Gbps, RAID 0/1/01/5/JBOD, NCQ, Hot-Plug, Native Gigabit LAN, 8 x USB2.0, HD Audio
• MCP55 (a.k.a. nForce 590 SLI MCP, printed "NF590-SLI-N-xx" on the chipset surface)
  
  • 28 PCI Express lanes with links 16,8,1,1,1,1
  • 1 x PATA, 6 x SATA at 3.0Gbps, RAID 0/1/01/5/JBOD, NCQ, Hot-Plug, Dual Native Gb LAN, 10 x USB2.0, HD Audio
  • DualNet, Teaming, TCP/IP Acceleration

MCP55 is exactly nForce 570 SLI for AMD (single chip), so it is identified with "nForce 570 SLI" by CPU-Z.

Chipsets

• nForce 650i Ultra = C55 + MCP51; PEG x16 only
• nForce 650i SLI = C55 + MCP51; PEG x16 or (x8, x8)
• nForce 680i SLI "Lite" (or Dual x16 SLI or Dual PCI-E x16 in the ASUS term) = C55 + MCP55; PEG (x16, x16, x8)
• nForce 680i SLI = C55XE + MCP55; PEG (x16, x16, x8) (and the hidden x8)

Again the only difference between 680i SLI "Lite" and 680i SLI is that 680i SLI has an extra (hidden) x8 link in its SPP. FYI

nForce 500 Series for Intel

• nForce 570 SLI = C19 + MCP51; PEG x16 or (x8, x8)
• nForce 590 SLI = C19 + MCP55; PEG (x16, x16, x8)

nForce4 for Intel

• nForce4 SLI = C19 + MCP-04; PEG x16 or (x8, x8) (The lanes in MCP are disabled!)
• nForce4 SLI X16 = C19 + MCP-04; PEG (x16, x16)
• nForce4 Ultra = C19 + MCP51; PEG x16
• nForce4 SLI XE = C19 + MCP51; PEG x16 or (x8, x8)

nForce 500 Series for AMD

• nForce 550 = MCP55; PEG x16
• nForce 570 Ultra = MCP55; PEG x16
• nForce 570 SLI = MCP55; PEG (x16, x8) or (x8, x8)
• nForce 590 SLI = C51XE + MCP55; PEG (x16, x16)

nForce4 for AMD

• nForce4 = MCP-04; PEG x16
• nForce4 Ultra = MCP-04; PEG x16
• nForce4 SLI = MCP-04; PEG x16 or (x8, x8)
• nForce4 SLI X16 = C51D + MCP-04; PEG (x16, x16)

More in the sticky thread Core 2 & AM2 Motherboards in AnandTech Forums, Part II, Section 9, 10, 11.

Drivers

There is no driver for SPP. In other words,

• "nForce 650i SLI/650i Ultra Drivers" = "nForce 430/410 Drivers" = MCP51 drivers
• "nForce 680i SLI Drivers" = MCP55 drivers

Even if 680i SLI "Lite" uses the 650i SPP, its drivers is still "nForce 680i SLI Drivers" = MCP55 drivers.

About C51 (or Crush 51)

C51 is the codename of the GeForce 6100 family chipsets for the AMD platform. Actually the project includes three chipsets:

• C51G & C51PV
  
  • SPP with integrated graphics for the AMD platform
  • 18 PCI Express lanes (16 for external graphics)
• C51D & C51XE
  
  • SPP with discrete graphics for the AMD platform
  • 18 PCI Express lanes (16 for external graphics)
• MCP51
  
  • MCP (for both AMD and Intel)
  • No PCI Express lane, 2 x PATA, 4 x SATA at 3.0Gbps, RAID 0/1/01/5/JBOD, NCQ, Hot-Plug, Native Gigabit LAN, 8 x USB2.0, HD Audio

C51G/PV + MCP51 is just the GeForce 6100/nForce 400 chipset family (PV = PureVideo = GeForce 6150). C51D/XE is used in nForce4 SLI X16/nForce 590 SLI for AMD. MCP51 is also used as the MCP of nForc4 Ultra/nForce 4 SLI XE/nForce 570 SLI/nForce 650i Ultra/nForce 650i SLI for Intel.

The above speculations are almost reasonable, except one point: no review site has ever mentioned the hidden extra x8 PCIe link in the 680i SLI SPP. But without this assumption (or at least some kind of hidden features that cost extra $50), the distinction between C55 and C55XE would be meaningless.