NVIDIA nForce® 680i SLI vs NVIDIA® Dual x16 SLI

[ShadowZERO]

I have decided to build a new Nvidia based Core 2 Duo system with an Asus motherboard, and i'm trying to narrow down my motherboard choices. There are 2 Asus motherboards that have almost identical specifications, and i'd like some imput on what, aside from around $50 dollars, is the difference between these 2 boards. Even though both boards are listed on Newegg.com as using the 680i chipset, the "Plus" version of this board is about $50 cheaper than the regular version. However, on the official Asus website, the "Plus" version of the board uses this chipset:

P5N32-E SLI Plus

NVIDIA® Dual X16 SLI
(C55+MCP55P; a.k.a. nForce®650i SLI & nForce®570 SLI)
ASUS HybridUp Technology
* Support SLI-Ready Memory Technology

The non "Plus" version uses the normal 680i chipset. I am trying to see if anyone could tell me the technical differences between the "Plus" and regular versions of the P5N32-E SLI, or more specifically, what the differences are between the "Dual X16 SLI" chipset and the true 680i chipset. From what i'm gathering, the "Dual x16 SLI" chipset is something Asus conjured up themselves, and is not an official Nvidia chipset. Aside from the price difference, what would i be losing out on by going with the cheaper "Dual X16 SLI" chipset instead of the true 680i chipset?

 

[Pyrokinetic]

The 680i chipset is a "dual x16 SLI" chipset. The term "dual x16" refers to the fact that the chipset can run both PCIE slots at the full x16 bandwidth at the same time. Note that the 650i chipset only has dual x8 bandwith when using both PCIE slots in SLI. The kicker is that having dual x16 SLI bandwidth offers no performance benefit over dual x8 SLI at this time. However, in the future with newer graphic cards, this might change.

As for the difference between the ASUS P5N32-E and the ASUS P5N32-E Plus, the "Plus" is merely a minor revision to the original. Both are genuine 680i chipsets. ASUS lists the board under "Nvidia chipsets" instead of the seperate "Nvidia 680i chipsets." How do you know it is then a 680i board? The Northbridge chip is list as a "C55" otherwise known as a 600 series chipset. Anandtech referred to the changes in a recent article: "The ASUS P5N32-E SLI is under going an update to the Plus version that features revised electrical components, BIOS changes, and new accessory items." http://www.anandtech.com/tradeshows/showdoc.aspx?i=2905&p=3
ASUS just needs to revamp their stupid and illogical subcategory headers for Intel motherboards.

ASUS also makes two other Nvidia "x16 SLI" boards for intel:

the 590 chipset -- ASUS P5N32 SLI (does not overclock well, a chipset better suited to AMD processors)

and the

NVIDIA® nForce4 SLI Intel® Editionx16 chipset -- ASUS P5N32-SLI SE (which also works with Core 2 Duo chips, a great and proven chipset that is not quite as feature-rich and won't overclock quite as high as the 680i chipset. However, at around $200 you might as well buy a 680i motherboard).

Also, Newegg made a mistake and listed the P5N32-E Plus as a 650i chipset. This is incorrect. The name "N32" indicates that this is a "dual x16 SLI" board and the 650i chipset is definitely not. See the following: http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2869&p=2

Hope this somewhat clears up your confusion.

 

[renethx]

This topic has been discussed in

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

The official answer from ASUS is here:

• P5N32-E SLI & Striker Extreme = C55XE + MCP55PXE
• P5N32-E SLI Plus = C55 + MCP55 (but functionally the same as the above)

NVIDIA claims that there is only one southbridge MCP55 (no MCP55PXE) and the distiction between C55 and C55XE is that C55XE has an extra x8 PCIe link. On the other hands, it was revealed that

• SPP of P5N32-E SLI Plus = SPP of P5N-E SLI (650i SLI) = C55-SLIX8N-A2 (the actual model number on the surface of the chip)
• SPP of P5N32-E SLI (680i SLI) = SPP of Striker Extreme (680i) = C55-SLIX16N-A2 (the actual model number on the surface of the chip)

Furthermore the 650i SLI SPP seems to have the same capability as the 680i SLI SPP despite its specs (support for FSB 1333MHz chips and SLI-ready memory) as seen in ASUS P5N-E SLI. Combining all the information, I concluded that there are two kinds of C55:

• C55 (C55-SLIX8N-A2)
  • 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 (C55-SLIX16N-A2)
  • 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 x8 link is unused)

and

• 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)

The detailed analysis is found in the two threads cited in the beginning.

 

[Pyrokinetic]

Ok, thanx renethx! I stand corrected. The Northbridge for the ASUS P5N32-E SLI Plus is the Northbridge from the 650i combined with the Southbridge from the 680i to create a "lite" dual x16 SLI setup.

Got me all confused because Nvidia is going to release an "official" 680i LT SLI offering. According to Dailytech, the LT version will have active cooling (at least with the reference models), only one gigabit ethernet connector, and will limit the memory controller to DDR2-800.
http://www.dailytech.com/article.aspx?newsid=6026

The ASUS P5N32-E SLI Plus must be indeed an ASUS specific custom setup as it retains the heatpipe cooling, the dual gigabit connectors, and higher DDR2 support of the 680i.

Anandtech said they were looking to review the Plus model, and I will eagerly await that review.