nForce 680i Overclocking

The defining area for the 680i chipset has to be overclocking. The 500 family chipsets for Intel performed fine in many areas, but they were one of the worst chipsets available for Intel in overclocking, topping out somewhere below 350 MHz on the bus speeds. This area kept many Enthusiasts from embracing the NVIDIA SLI solution for their Core 2 processors. It appeared NVIDIA had designed the 500 chipset family for spectacular overclocking on the 200 MHz HTT AMD AM2 chipset. The problem, of course, is that Core 2 processors were released at 1067 FSB (266 base bus speed), and the 500 family chipsets did not have anywhere close to the headroom of the competing Intel chipsets.

All of that has changed, NVIDIA tells us, with a 680i that can do 1333 FSB and more and DDR2 memory speeds of 1200 and beyond. To test NVIDIA's claims we tested the EVGA 680i SLI using the following setup:

Overclocking Testbed
Processor: Intel Core 2 Extreme X6800
Dual Core, 2.93GHz, 4MB Unified Cache
1066FSB, 11x Multiplier
CPU Voltage: Default (Auto) to 1.575V
Cooling: Tuniq Tower 120 Air Cooling
Power Supply: OCZ GameXstream 700W
Memory: Corsair Dominator 1142MHz (2x1GB)
(Micron Memory Chips)
Hard Drive Hitachi 250GB 7200RPM SATA2 16MB Cache
Maximum OC:
(Standard Ratio)
363 (1452 FSB) x 11 - 3.993GHz at 1.575V (+36.3%)
334 (1336 FSB) x 11 - 3.675GHz at Default Voltage
Maximum OC:
(Reduced Multiplier)
525 (2100 FSB) x 7 - 3.675GHz at Default Voltage

The overclock results are not a mistake. We managed to reach right at 4.0GHz with an X6800 at 1.575V. This represented the standard 11x ratio at a 1452 FSB. Even more spectacular was the reduced multiplier overclocking, where we reached a 2100 FSB (525 base) at a 7X multiplier AT DEFAULT VOLTAGE.

These results were with air cooling using a Tuniq 120 air cooler, which sandwiches a 120mm fan in a finned heatpipe core as pictured above.

Click to enlarge

One of our X6800 processors reached 2100 FSB, confirming NVIDIA's claims of overclocking an X6800 in their labs to 2070 FSB. Not only did we reach 2100 FSB (525) at a 7X multiplier (3.675GHz), we managed to reach that speed at default voltage. The system has run at those settings for several days without incident and has handled every test and benchmark we have thrown at the system. However, it should also be pointed out that a second X6800 CPU would not overclock 1 MHz higher than 1900 FSB (450) on this same motherboard, even though that X6800 reached a similar 4GHz maximum overclock and similar "default voltage" overclocks.

We have yet to find anything obvious that would explain these differences in maximum FSB in the X6800 chips we tested. Revision and Stepping explained nothing, and we also had four retail E6600 we tested that would not reach above 1800 FSB. We are looking into these findings further and hope to find some explanations to share with you that will explain these maximum FSB differences among 4MB Cache Core 2 chips.

Click to enlarge

Interestingly, all of the 2MB cache Core 2 processors we tested reached at least 2000 FSB, with the two tested E6300 reaching 2100 FSB (522x7 and 6x525). We were prepared to call the amount of cache the defining difference in FSB performance until the late X6800 reached 2100 in our labs and NVIDIA confirmed their own 2070 results with an X6800 Extreme. We are much more confident that 2MB Cache chips can top 2000 FSB and we are very anxious to find something that will help you identify 4MB cache chips that will reach the "magic" 2000, 2070, and 2100 FSB overclocks.

Overall overclocking performance with the 680i was spectacular, and the results should excite any of you who want to do some serious overclocking with a Core 2 processor. At the very least the nForce 600i chipset family gives shoppers new choices in motherboards that will make the most of their Core 2 processor.

Gaming Performance Final Words


View All Comments

  • 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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