One of the features unique to the nForce 590SLI and 680i SLI MCP is a system called LinkBoost. If a GeForce 7900 GTX or GeForce 8800 is detected on either MCP then LinkBoost will automatically increase the PCI Express and MCP HyperTransport (HT) bus speeds by 25%. This increases the bandwidth available to each PCI Express and HT bus link from 8GB/s to 10GB/s.

Since this technology increases the clock speed of the PCI Express bus by 25% to the x16 PCI Express graphics slots, NVIDIA requires certification of the video card for this program to work automatically. In this case, the 7900GTX and 8800 series are the only compatible cards offered, although you can manually set the bus speeds and achieve the same results depending upon your components. We feel this feature is worthwhile for those users who do not want to tune their BIOS and go through extensive test routines to find the best possible combination of settings.

In essence, NVIDIA is guaranteeing their chipset's PCI Express and HT interconnect links are qualified to perform up to 125% of their default speeds without issue. While LinkBoost is an interesting idea, the 25% increase in PCI Express x16 slots and HT bus speeds yielded virtually the same performance as our system without LinkBoost enabled in most cases.

Its actual implementation did not change our test scores in single video card testing but did provide a 1%~2% difference in SLI testing at resolutions under 1600x1200 in several game titles. The reason for the minimal increases at best is that the performance boost is being applied in areas that have minimal impact on system performance as the link to the CPU/Memory subsystem is left at stock speed thus negating the true benefits of this technology.


As part of the overhaul of the networking features first introduced in the NVIDIA nForce 590SLI and now 680i SLI Series, FirstPacket is a packet prioritization technology that allows latency-sensitive applications and games to effectively share the upstream bandwidth of their broadband connection. Essentially this technology allows the user to set network data packets for applications and games that are more latency sensitive with a higher queue priority for outbound traffic only.

FirstPacket is embedded in the hardware and offers driver support that is specifically designed to reduce latency for networked games and other latency-sensitive traffic like Voice over IP (VoIP). When network traffic constrains a connection, latency is increased which in turn can result in dropped packets that would create a jitter and delay in VoIP connections or higher ping rates to the game server resulting in stutters and decreased game play abilities.

In the typical PC configuration, the operation system, network hardware, and driver software are unaware of latency issues and therefore are unable to reduce it. The standard interfaces that allow applications to send and receive data are basically identical to the OS in a typical system. This type of design results in latency-tolerant and large packet applications like FTP or Web browsers filling the outbound pipeline without regards to the needs of small packet and very latency-sensitive applications like games or VoIP applications.

FirstPacket operates by creating an additional transmit queue in the network driver. This queue is designed to provide expedited packet transmission for applications the user determines are latency-sensitive applications. The ability of the designated applications to get preferential access to the upstream bandwidth usually results in improved performance and lower ping rates. The FirstPacket setup and configuration is available through a revised Windows based driver control panel that is very easy to use.

In our LAN testing, we witnessed ping rate performance improvements of 22% to 36% during the streaming of video from our media server while playing Serious Sam II across three machines on our LAN. We noticed ping rate performance improvements of 14% to 33% while uploading files via BitTorrent and playing Battlefield 2 on varying servers.

The drawback at this time is that only outbound packets are prioritized so if you spend more time downloading than uploading the FirstPacket technology will have little impact on your computing experience. Worth mention is that nearly all broadband connections have a lot more downstream bandwidth than upstream bandwidth, so focusing on prioritizing outbound traffic does make sense. Also, the upload time for our test file increased by 41% with FirstPacket turned on but the overall gaming experience was significantly better. However, in NVIDIA's defense they cannot control the behavior or quality of service on other networked clients, so FirstPacket addresses the services NVIDIA can control - namely uploading.

nForce 650i SLI & 650i Ultra DualNet, Teaming, and TCP/IP Acceleration


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  • fenacv - Tuesday, January 8, 2008 - link">
    If you don't really care the prefermace, I found it's onsale just buy one only 138 bucks. It's cheap.
  • TheBeagle - Friday, December 8, 2006 - link

    I'm wondering if these touted new 680i boards are vaporware, especially the Gigabyte GA-N680SLI-DQ6 board. Ever since you first alerted us to the fact that the 680i chipset was replacing the 590 version, I've been waiting to see this whole new array of motherboards. However, aside from a few boards (ASUS and a few others) the major board manufacturers haven't been forthcoming with these products. Maybe this is just going to be some sort of a big Christmas present that Santa delivers on the holiday. If you guys at AnandTech have some info on this, I'd sure like to hear about. Thanks Reply
  • mbf - Wednesday, November 29, 2006 - link

    I, for one, am going to seriously miss the native hardware firewall of the nForce3 and nForce4 chipsets, so I'm anything but "thankful" for seeing it "jettisoned into deep space." Actually, this was one of the coolest features of the nForce chipsets and truly innovative.

    nVidia's stance as to removing it because the functionality is built into Windows Vista doesn't ring true. A software solution can never work as efficiently and transparently as a hardware solution. And what of the people having no intention to switch to Windows Vista, and there are many reasons for not wanting to. They're practically left out in the cold.

    I second the opinion that nVidia probably botched the hardware in some form or other, although the hardware firewall works quite well on my nForce3 250gb based system, once you get familiar with its quirks. This actually doesn't bode well for nVidia's "inventiveness" and "forward-thinking" (think DualNet), since chances are nVidia will drop support completely rather than work out the bugs that inevitably will be there. Removing the hardware firewall is the best example of this.

    Also, and this is a bit off-topic in regard to the rest of this topic, wasn't there supposed to be ECC memory support in the new northbridge for the 680i chipset? I remember reading about the northbridge also being used in the new nForce Pro series chipsets. Another feature that has been removed in the mean time?
  • skrewler2 - Monday, November 13, 2006 - link

    How was the Tuniq Tower 120 on the board? I've heard lots of people complaining about backplates not fitting right on this board because the back of the mobo has lots of capacitors... Did you need to do any modding or did it just work?

  • Gary Key - Monday, November 13, 2006 - link

    I used the Scythe Infinity in my testing, Wes used the Tuniq. I did try the Tuniq and it was okay with an extra pad on the backplate that negated any damage to the capacitors. Reply
  • mlau - Monday, November 13, 2006 - link

    Did you test a recent Linux kernel on this board?
    Which components are supported (I don't care about "raid"),
    and how buggy are the HPET, (IO-)APIC and ACPI implementations?
  • Governator - Saturday, November 11, 2006 - link

    First off, very well done article guys, but I've a question on the layouts with regards to PCI slots so far with the Asus and Evga; are we to expect similar layouts with upcoming boards from other manufacturers? I ask because I'm planning on a water cooled SLI setup upon a 680i and am planning on an X-Fi card but not sure if I'll be able to use the middle PCI slot, TIA...

  • Gary Key - Sunday, November 12, 2006 - link

    Most of the 680i boards have the same basic layout. On the Asus Striker board you should be able to use the X-FI with most watercooled SLI setups as an example. It will all depend on your setup but you can kiss the middle PCIe slot good-bye. ;) Reply
  • Governator - Saturday, November 18, 2006 - link

    Hi Gary, sorry I meant to reply sooner but thanks for this. I'm hoping I'll be in good shape with the fact that I'll be using the new 8800GTX water block codeveloped by BFG Tech from Danger Den which appears that it'll only take up one slot allowing for that bottom PCI slot to go to the X-Fi card, thoughts? TIA ;) Reply
  • deathwalker - Friday, November 10, 2006 - link

    I wonder if there are Matx mobo's in the future for the 600 series chipsets. Reply

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