[p]'s Nvidia 780i Overclocking Guide.

[[p]wnzor]

Hey all, though this might help a few of you. The originals are posted in the 411overkill forums here...

http://www.411overkill.com/forum/phpBB3/index.php

The un-official 780i Overclocking Guide...short and sweet.

I have found the following voltages to be rock solid from 1066-1800QDR on the 680i & 780i. Of course your RAM and CPU voltages will vary. Yes I still Link/Sync FSB & RAM. Disable all Spread Spectrums & CE1/Speedstep/Thermal stuff. Fans on 100% for now, you can turn them down later. SLI ready memory enabled/expert if you have the option.

CPU ~1.4v (actual via CPUid) a good starting point for Kentsfield >3.2Ghz…faster=more***
RAM Run at manufacturers specified voltage only.
FSB 1.3v....(1.4v ~1600QDR+)
SPP/NB 1.4v...(1.45v ~1700QDR+)
MCP/SB 1.525v
HT 1.25v (aka MCP<>SPP)
AUX 1.5v(auto) (not applicable on 680i)
GTRLEDs (auto) (not applicable on 680i)

***voltage stated for Kents, less voltage for Yorkies...ie ~1.35v.

Notice they are all still in the "green safe zone." If you set those voltages, regardless of QDR and you are not stable...~95% chance it's your RAM settings/voltage or CPU voltage, or you hit a nasty FSB "hole." Of course your CPU voltage may vary wildly, but you knew that because you read the first guide right?



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CPU VOLTAGE UPDATE!!!! Kentsfields ONLY!

I have been getting entirely too many questions regarding CPU voltage...so let me explain a few things.

#1 As I have preached time and time again, every CPU is different. Not every Q6600 is gonna do 3.6Ghz...most will, but not all.

#2 Every single CPU on the planet is gonna require different amounts of voltage to "get stable" at a given speed, even among CPUs from the same batches...they are like fingerprints...unique. I've seen a Q6600 do 4Ghz on 1.39v...my Q6600 requires 1.62v to get to 3.9Ghz...we are all effected by this. Luck of the draw.

#3 I cannot possibly tell you what your voltage should be at a given speed, I can tell you what I suspect it might be, but that is an assumption on my part. That is why I put 1.4v ACTUAL VIA CPUID as a STARTING POINT.

#4 Try to remember, 3.6Ghz, while fairly common, is NOT a "mild" overclock. It is actually quite extreme, 66% by my estimations. Before this current line up of CPUs came out I would have killed for a 33% overclock. You paid for 2.4Ghz, and I'll all but garantee you 3.2Ghz, 3.6Ghz is really quite amazing. If you want a garanteed overclock...shell out $1000 for an Extreme Edition.

Remember this is a guide...not a Bible. Your gonna have to put in work and cut your teeth just like the rest of us Uber Geeks did, I've been overclocking for about 10 years now...and I still ask questions...the day you think you know it all...is the day you're gonna fail.

Now that I'm done preaching I'll tell you how I deal with CPU voltage. It may not be right...it might even be dangerous, but that is how I roll.

When shooting for 3.6Ghz or greater with the current Kentsfield CPUs, I set the voltage to 1.5v in BIOS right off the bat. I know you are supposed to up the voltage slowly...and all that. I don't do it like that. Now, you should know...I have my cooling under control BEFORE I even attempt to overclock...and I'm mentally and financially prepared if I should kill a chip. I have given much more voltage 1.65v+ to my various C2D chips...none have died, yet. However...my cooling is up to par. If you are scared...then don't do this. If you are scared, then you should probably not touch voltages at all and just see how far default voltage takes you and be happy. Like I said, 3.6Ghz is extreme...you might break some eggs making the omlette.
Once/if I boot, then I start rebooting lowering voltages a notch at a time until I stop booting (Blue screen/freeze/whatever). Then I go back up one notch, and start stability testing an monitoring temperatures. If not stable, I reboot and give it a bit more until I'm stable or I start getting too hot. If I get too hot I start thinking, do I really need this overclock, or, how can I get these temps down. If overclocking is your thing, this little conversation will never end. If gaming is your thing, I suggest you overclock only as much as you need to to get the performance that you desire, then enjoy your machine. For me, the fun is seeing how high I can go...we all have our own personality quirks to bear. That is how I get 'er done.

Again, I, nor eVga, will not be responsible for what you do with this information. You have been warned.
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A bit more information for you new people, in lamens terms.

FSB
This is basically how fast your CPU talks to the rest of your system. It (along with the multiplier)is also a contributing factor in determining overall CPU speed. Faster is better in most cases.

QDR
This is the effective FSB speed, found by simply multiplying the true FSB times four.
(4 x FSB=QDR) True FSB speed is more important. Faster is better in most cases.

Multiplier
This along with FSB determines how fast your CPU operates.
(266 x 9 = 2400Mhz or 2.4Ghz) Notice how the QDR is not included in this equation. Higher multipliers are generally better.

DDR Ram (Thoughtfully corrected by dilburt) Future Ram guide coming...

Depending how long you have been around, you may remember SDRam. That stood for (Synchronous Dynamic Ram) Well, you guessed it DDR stands for (Double Data Rate Synchronous Dynamic RAM.) So when you look at DDR 800, that number is found by multiplying by two, thus the double.
(DDR800= 2 x 400Mhz) The Ram is actually operating at 400Mhz.

Now the faster your RAM goes, generally speaking the better. Only it's called bandwidth. Think about a highway. If DDR800 is say an 8 lane highway, than DDR1066 is say a 12 lane highway...meaning it has the ability to pass more data. That doesn't mean it will pass more data, but that it could, in theory.

Another thing about Ram is latencies, if we look at Ram's Mhz as a highway, like I have above, then latencies would be the speed of the cars traveling on that highway. I know it's a tough concept to grasp, but lets just say the speed limit on the DDR800 or 8 lane highway is faster than the speed limit on the DDR1066 or 12 lane highway. The goal is to get the most data or cars moved from point A to point B as fast as possible. Since the cars on the 8 lane highway are traveling faster, they are gonna get from point A to point B faster. Unless there are so many cars, so much data, that they cannot fit on the 8 lane highway...then the 12 lane highway will be faster. As things sit today, with our current CPUs, and 8 lane highway or DDR800 is more than enough.

Occasionally with some programs this won't be entirely true...but for the most part it is.

Still with me?

Most agree that a 1:1 FSB to RAM Ratio works the best for a balance of stability and performance. Meaning the Ram is running at the same speed as the FSB.

So using your CPU as an example....

You have a 266Mhz FSB, 1:1 with Ram would be achieved running DDR533. Remember Ram is double data rate. The equation looks like this...
(DDRMhz= 2 x RamMhz : FSBMhz x 4 =QDR) = 1:1

or....2.4Ghz or 2400Mhz

(DDR533= 2 x 266Mhz : 266Mhz x 4 = 1066QDR) = 1:1 =2400Mhz

Now if you wanted to overclock to say 3.6Ghz or 3600Mhz...it would look like this.

(DDR800= 2 x 400Mhz : 400Mhz x 4 = 1600QDR) = 1:1 =3600Mhz

So people buying DDR1066 Ram are wanting to run it 2x as fast as thier FSB, or a 2:1 ratio. This is rarely beneficial, you will notice most of the people with good overclocks are running close to a 1:1 ratio.

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Kentsfield popular Quad configurations.

CPU FSB QDR Multi RAM Final MHZ
Q6600 266Mhz 1066QDR 9x 533Mhz =2400Mhz
Q6600 333Mhz 1333QDR 9x 667Mhz =3000Mhz
Q6600 400Mhz 1600QDR 8x 800Mhz =3200Mhz
Q6600 375Mhz 1500QDR 9x 750Mhz =3375Mhz
Q6600 450Mhz 1800QDR 8x 900Mhz =3600Mhz
Q6600 400Mhz 1600QDR 9x 800Mhz =3600Mhz
Q6600 416.6Mhz 1666QDR 9x 833Mhz =3750Mhz
Q6600 425Mhz 1700QDR 9x 850Mhz =3830Mhz
Q6600 450Mhz 1800QDR 9x 900Mhz =4050Mhz
Q6600 466.6Mhz 1866QDR 9x 933Mhz =4200Mhz
Q6600 475Mhz 1900QDR* 9x 950Mhz =4275Mhz
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Q6700 266Mhz 1066QDR 10x 533Mhz =2660Mhz
Q6700 333Mhz 1333QDR 10x 667Mhz =3330Mhz
Q6700 375Mhz 1500QDR 10x 750Mhz =3750Mhz
Q6700 400Mhz 1600QDR 10x 800Mhz =4000Mhz
Q6700 416.6Mhz 1666QDR 10x 833Mhz =4166Mhz
Q6700 425Mhz 1700QDR 10x 850Mhz =4250Mhz
Q6700 450Mhz 1800QDR 10x 900Mhz =4500Mhz
Q6700 466.6Mhz 1866QDR 10x 933Mhz =4666Mhz
Q6700 475Mhz 1900QDR* 10x 950Mhz =4750Mhz
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Qx6850 333Mhz 1333QDR 9x 667Mhz =3000Mhz
Qx6850 375Mhz 1500QDR 9x 750Mhz =3375Mhz
Qx6850 400Mhz 1600QDR 9x 800Mhz =3600Mhz
Qx6850 416.6Mhz 1666QDR 9x 833Mhz =3750Mhz
Qx6850 425Mhz 1700QDR 9x 850Mhz =3830Mhz
Qx6850 450Mhz 1800QDR 9x 900Mhz =4050Mhz
Qx6850 466.6Mhz 1866QDR 9x 933Mhz =4200Mhz
Qx6850 475Mhz 1900QDR* 9x 950Mhz =4275Mhz

Qx6850 333Mhz 1333QDR 10x 667Mhz =3333Mhz
Qx6850 375Mhz 1500QDR 10x 750Mhz =3750Mhz
Qx6850 400Mhz 1600QDR 10x 800Mhz =4000Mhz
Qx6850 416.6Mhz 1666QDR 10x 833Mhz =4160Mhz
Qx6850 450Mhz 1800QDR 10x 900Mhz =4500Mhz
Qx6850 466.6Mhz 1866QDR 10x 933Mhz =4666Mhz
Qx6850 475Mhz 1900QDR* 10x 950Mhz =4750Mhz

Qx6850 333Mhz 1333QDR 11x 667Mhz =3663Mhz
Qx6850 375Mhz 1500QDR 11x 750Mhz =4125Mhz
Qx6850 400Mhz 1600QDR 11x 800Mhz =4400Mhz
Qx6850 416.6Mhz 1666QDR 11x 833Mhz =4582Mhz
Qx6850 450Mhz 1800QDR 11x 900Mhz =4950Mhz
Qx6850 466.6Mhz 1866QDR 11x 933Mhz =5126Mhz
Qx6850 475Mhz 1900QDR* 11x 950Mhz =5225Mhz
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Yorkfield popular Quad configurations.**

CPU FSB QDR Multi RAM Final MHZ
Q9450 333Mhz 1333QDR 8x 667Mhz =2660Mhz
Q9450 400Mhz 1600QDR 8x 800Mhz =3200Mhz
Q9450 416.6Mhz 1666QDR 8x 833Mhz =3333Mhz
Q9450 450Mhz 1800QDR 8x 900Mhz =3600Mhz
Q9450 466.6Mhz 1866QDR 8x 933Mhz =3733Mhz
Q9450 475Mhz 1900QDR* 8x 950Mhz =3800Mhz
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Q9550 333Mhz 1333QDR 8.5x 667Mhz =2830Mhz
Q9550 400Mhz 1600QDR 8.5x 800Mhz =3400Mhz
Q9550 416.6Mhz 1666QDR 8.5x 833Mhz =3541Mhz
Q9550 450Mhz 1800QDR 8.5x 900Mhz =3825Mhz
Q9550 466.6Mhz 1866QDR 8.5x 933Mhz =3966Mhz
Q9550 475Mhz 1900QDR* 8.5x 950Mhz =4040Mhz
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Qx9650 333Mhz 1333QDR 9x 667Mhz =3000Mhz
Qx9650 375Mhz 1500QDR 9x 750Mhz =3375Mhz
Qx9650 400Mhz 1600QDR 9x 800Mhz =3600Mhz
Qx9650 416.6Mhz 1666QDR 9x 833Mhz =3750Mhz
Qx9650 425Mhz 1700QDR 9x 850Mhz =3830Mhz
Qx9650 450Mhz 1800QDR 9x 900Mhz =4050Mhz
Qx9650 466.6Mhz 1866QDR 9x 933Mhz =4200Mhz
Qx9650 475Mhz 1900QDR* 9x 950Mhz =4275Mhz

Qx9650 333Mhz 1333QDR 10x 667Mhz =3333Mhz
Qx9650 375Mhz 1500QDR 10x 750Mhz =3750Mhz
Qx9650 400Mhz 1600QDR 10x 800Mhz =4000Mhz
Qx9650 416.6Mhz 1666QDR 10x 833Mhz =4160Mhz
Qx9650 450Mhz 1800QDR 10x 900Mhz =4500Mhz
Qx9650 466.6Mhz 1866QDR 10x 933Mhz =4666Mhz
Qx9650 475Mhz 1900QDR* 10x 950Mhz =4750Mhz

Qx9650 333Mhz 1333QDR 11x 667Mhz =3663Mhz
Qx9650 375Mhz 1500QDR 11x 750Mhz =4125Mhz
Qx9650 400Mhz 1600QDR 11x 800Mhz =4400Mhz
Qx9650 416.6Mhz 1666QDR 11x 833Mhz =4582Mhz
Qx9650 450Mhz 1800QDR 11x 900Mhz =4950Mhz
Qx9650 466.6Mhz 1866QDR 11x 933Mhz =5126Mhz
Qx9650 475Mhz 1900QDR* 11x 950Mhz =5225Mhz
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I have highlighted by bolding some of what I see as the more popular configurations. There are more options availble, but the above list gives you a nice idea...while missing the current known FSB holes on.

*780i peaks FSB right around here from my testing with a Q6600. However, a new CPU could change things slightly.

**Probably, they haven't come out yet, but I focused my inner geek, and those are the specs I came up with.

Extreme Editions: As of now, I think the multiplier adjustment can only be changed by full numbers, a future BIOS update may change this with Yorkies, but I doubt it.

I only did quads, quads with big caches and decent multipliers, because...well, if you can afford this board you can go get a quad.

I also have a feeling Intel is "sandbagging" us pretty hard with the "Yorkie" lineup since AMD isn't threatening them. I'd be very surprised if we didn't see CPUs with 9x & 9.5x multipliers before the end of summer...but they will cost a premium.












SPP might need 1.4v in some instances!




Always keep your CPU under 65C under load. I will not be responsible if you break something. I may change the data if I find out or learn something new. So far this has gotten me to 3.9Ghz, only thing stopping me from going higher is Air cooling and a voltage hungry chip. As always, these numbers should work, but don't freak out if they don't...there are always small variations motherboard to motherboard, CPU to CPU. If you run into a problem, let me know by posting below...I will answer as soon as I can to the best of my ability. If you absolutely need something you can PM me, however I would rather you posted here so that others may learn from our mistakes.

Also, if you dis-agree that's fine. I might be wrong about something. Trust me I'm wrong everyday I have a girlfreind, but lets try to have a civil conversation and keep the flaming to a minimum so that this post can act as a learning journal for new people.

If you can’t afford to replace it, don’t overclock it. [p]

http://www.411overkill.com/forum/phpBB3/viewforum.php?f=19

EDITED 2/11/2008...new info, thanks [p] admin @411overkill.com

[[p]wnzor]

My bad...

[psygnosi]

Thanks pwnzor! Got my Asus P5N-T Deluxe and Intel Q6600 cpu to 3.60Ghz on air! Sweet! Now just have to get better ram to get it from 400 to 450 to get to 4.0Ghz.