NVIDIA 680i: The Best Core 2 Chipset?
by Gary Key & Wesley Fink on November 8, 2006 4:45 AM EST- Posted in
- CPUs
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:
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.
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.
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.
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:
| EVGA 680i SLI 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.
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Wesley Fink - Thursday, November 9, 2006 - link
The other time you might need a fan on the northbrdige is when using water cooling or phase-change cooling. There is no air-flow spillover from water-cooling the CPU like there is with the usual fan heatsink on the CPU, so the auxillary fan might be needed in that situation.Wesley Fink - Thursday, November 9, 2006 - link
The 680i Does NOT require active notrthbridge cooling and is shipped as a passive heatpipe design. At 80nm it is much cooler than the 130nm nVdia chipsets. The fan you see in the pictures is an included accessory for massive overclocking, much like Asus includes auxillary fans in their top boards.In our testing we really did not find the stock fanless board much of a limitation in overclocking as the northbridge did not get particularly hot at any time. We installed the fan when we were trying to set the OC record and left it on for our 3 days at 2100 FSB. Since it is a clip and 3 screws to install we left it on.
IntelUser2000 - Monday, November 13, 2006 - link
That's funny. A cooler running one consuming more power. Must be the die size is much larger :D.
yacoub - Thursday, November 9, 2006 - link
ah okay thanks for that clarification! =)yacoub - Thursday, November 9, 2006 - link
NTune would be a lot more interesting if it wasn't so slow to respond to page changes, cumbersome, and a gigantic UI realestate hog.The same functionality in a slimmer, more configurable, and efficient UI design would be highly desireable.
yacoub - Thursday, November 9, 2006 - link
and actually, that goes for the entire NVidia display/GPU settings configuration panel.Khato - Wednesday, November 8, 2006 - link
Each CPU is going to have a max FSB clock that it'll run stably at for the same reason that it has a max core logic frequency. The main difference here is that you have two possible barriers: signal degredation due to the analog buffers not being designed for such high speed and then whatever buffer logic there is in the CPU to clock cross from FSB to core not liking the higher frequency. I'm kinda leaning towards the buffer logic being the limiting factor, since I'd expect the manufacturing variance in the analog buffers to be minimal. That and the described 75MHz variance in top FSB frequency between various processors sounds reasonable for non-optimized logic.Staples - Wednesday, November 8, 2006 - link
I have no need for SLI. Makes the board more expensive and an SLI setup is just not worth it to me. I was about to buy a P965 chipset but now I am interested in a the 650i Ultra. Will we see a review of this chipset in the future? Most of it seems to be exactly the same as the 680i however it does lack some features and I am afraid that those missing features may affect performance. As it stands now, do you expect the performance of the 650i Ultra to perform identical to the 680i SLI?Gary Key - Wednesday, November 8, 2006 - link
We do not, we do expect the 650i SLI to perform closely to it. We will have 650i boards in early December for review. :)
Pirks - Wednesday, November 8, 2006 - link
is this functionality where you can overclock your CPU and FSB and memory on the fly without rebooting Windows available only on nForce mobos? I'm a stability freak and I want to be able to raise and lower my clocks and voltage on the fly, similar to the way Macs do this - they spin their fans under load and become totally quiet when idle - I wanna do the same so that my rig is dead quiet when idle/doing word/inet/email/etc and becomes noisy and fast OCed beast when firing up Crysis or something. and I want this Mac-style WITHOUT rebooting Windowsso do I have to buy nVidia mobo for that?
600i series only or earlier nForce 4 or 5 series will do as well?
I still can't dig what's up with these "dynamic BIOS updates that _require_ reboot to work" - so can you OC without rebooting or not? if yes - what are these BIOS options that nTune changes that DOES require reboot?
could you happy nTune owners enlighten me on that stuff? thanks ;)