My i7-2600k Gigabyte GA-Z68X-UD3H Noctua NH-D14 OVERCLOCK LOG (with Load Line Calibration)

DISCLAIMERI know there are a lot of thread like this, but there are few with load line calibration that I found. Google almost always led me to other forums when searching the matter. I am posting this here to share how Load Line Calibration has helped make my overclock stable. Most of the Sandy Bridge OC tutorials here don't fully explain it, so I am hoping I can ad to it.

I wanted to write down my recent experience overclocking my 2600k to 4.7+ghz on air for the purpose of Folding@home 24-7. Rig is in my signature. Highlights are...

2600k D2 stepping
Gigabyte GA-Z68-UD3H F12 Bios
Noctua NH-D14 Cooler
Asus GTX670 Non-Top
2x4GB Samsung RAM 1600mhz

Initially I tried OCing to 4.5ghz by only adjusting the multiplier to 45 and changing the power to 150w. It would boot but was unstable. I then tried the same configuration, but with 1.4v VCore instead of auto. This would appear stable but resulted in x124 BSOD under load while folding. After many tested configurations, I was about to conclude my chip was just a dud and could barely do 4.5ghz, when I found these articles and posts regarding Load Line Calibration.

Hardforum Asus P8P67 Overclocking
Gigabyte Z68XP-UD5 LGA 1155 Motherboard Review
Load Line Calibration Settings on Gigabyte Motherboards
GIGABYTE GA-Z68X-UD7

In short, I found Gigabyte boards have a hard time delivering the BIOS Vcore setting without Load Line Calibration (to be called LLC from now on), specifically LLC6 or 7. My board, with 1.4v Vcore set in BIOS, only delivered 1.284v under load. No wonder I was getting x124 BSODs all the time @ 4.5ghz, I was basically trying to run @ 1.28v (yes I know some people can run at that voltage but I don't think I am one of them). After reading those posts/reviews, I learned LLC6 and 7 on Gigabyte Z68 board get very close to the actual BIOS Vcore. For me, 1.4v in the BIOS with LLC6 = 1.414v under load. 1.38v = 1.392-1.404. This has enabled me to finally get a stable 4.7ghz overclock going. With 1.4v, LLC6, I am able to run 4.7ghz which I have tested so far @100% load for 40 hours straight folding@home.

Here is a chart I "borrowed" from Eldonko @ hardwarecanucks.com As you can see, there are great variations between between the voltage you select in the bios and what you actually get in Windows (I am using CPU-Z and HWinfo64 to read my voltages). LLC6 & 7 seem to yield the closest values to the desired voltage.



If we compare the commonly needed voltages from Sin0822s Tutorial on Sandy Bridge Overclocking here, we see that I was not getting the necessary voltages to run a 4.5ghz OC, even with 1.4v enabled in the bios. I need LLC to make the 1.4v an actual 1.4v (otherwise it will just be 1.29v under load).

Just as Sin0822 recommended, once I got the recommended 1.4v into my CPU, my overclock stabilized, in fact, I was able to push up 4.7 and 4.8ghz with the same 1.4v. (+Rep Sin0822)

I hope my findings will help others with Gigabyte boards and Sandy Bridge CPUs get the most out of their overclocks with LLC.



Currently I have tested the following configurations...


All configurations are with all C-states enabled. Everything is stock except for Multiplier, TDP being 150, Vcore as noted, and LLC as noted.

4.5ghz 1.4v NO load line calibration = a load voltage of 1.284. No wonder I was getting BSODs all the time while folding!

4.7ghz 1.4v LLC6 Stable for 40 hours (1.416v actual voltage@load) 73C max average on hottest core. Photo 1 Photo 2

4.7ghz 1.375v LLC6 Windows 7 froze on bootup (too little juice I guess)

4.7ghz 1.39v LLC6 Tested 1hr stable (1.404v actual@load). Similar temps 72C max@load

4.7ghz 1.38 LLC6 Tested 2hr stable (1.392-1.404v fluctuation). Max temp 70C

4.8ghz 1.4v LLC6 POST GOOD , WIN7 BOOT GOOD. Stable for 10 days.

4.9ghz 1.4v LLC6 POST Good, Win7 boot Good, BSOD x124 after 5 minutes@low load.

4.8ghz 1.4v LLC6 CPU PLL Enabled. 2133mhz, 1.5v DIMM, & 1.15v QPI/Vtt = VCCIO. BSODx124 after a night of straight folding.

4.9ghz @1.425v LLC6 (1.428 actual). PLL overvoltage enabled. 1600 Cl 9 RAM @ 1.35v & stock VTT/PLL (VCCIO). BSODx124 in 10 minutes of folding.

4.8ghz @1.4v LLC6 (1.416 actual). PLL overvoltage enabled. 1600 Cl 9 RAM @ 1.35v & stock VTT/PLL (VCCIO). BSOD x124 after long duration folding.

4.8ghz 1.425v LLC6 CPU PLL Enabled. 2133mhzCl10, 1.6v DIMM, & 1.15v QPI/Vtt = VCCIO. BSOD x124 after long duration folding.

4.8ghz 1.455v LLC6 CPU PLL Enabled. 2133mhzCl10, 1.6v DIMM, & 1.15v QPI/Vtt = VCCIO. Stable for 10 passes of IBT.

4.9ghz 1.45v LLC6 CPU PLL Enabled. 2133mhzCl10, 1.6v DIMM, & 1.15v QPI/VttVCCIO, 1.5 PLL. BSOD x124 within 5 minutes of folding. 78C max temp.

Currently testing 4.8ghz 1.425v LLC6 CPU PLL Enabled. 2133mhzCl10, 1.6v DIMM, & 1.15v QPI/VttVCCIO, 1.5 PLL.
Edited by valkeriefire - 8/13/12 at 3:09pm

Yes, holding stable at 4.8ghz. I've got about 8 hours into it now.

UPDATE: 5 days of non-stop folding on the 4.8ghz OC. Very stable so far. I may up the voltage and try for 4.9 or 5.0ghz if I can stay under 80C.
Edited by valkeriefire - 7/26/12 at 9:21am

UPDATE: The 4.8ghz OC is fully stable. I have completed 8.5 days of folding with it without a single crash.

I OC'd my Samsung RAM to 2133mhz while keeping the stock clocks and voltages (1.5v and Cl 11). This increased my folding speed by 5.5%.

I also tried 5.0ghz at 1.45v with LLC6. It was stable, but it putting too many volts out. Per CPU-Z I was actually getting 1.5-1.55v under load. Way more than I wanted. I dialed back the voltage to 1.425v in the bios, and got me around 1.44v in CPU-Z, but that OC crashed with a BSOD shortly after starting windows.

Looks like 5.0ghz is doable, but it will need more than 1.425v.

Read this guide for a basic overview...

http://forum.giga-byte.co.uk/upload/files/Gigabyte%20Sandy%20Bridge%20Overclocking%20Guide.pdf

then read this...

http://www.overclock.net/t/908782/sandy-bridge-overclocking-guide-ocn-members-only


My settings are...

Motherboard Tweaker/Adv Frequency Settings:
CPU Clock Ratio: 48
Turbo Power Limit: 150
Core Current Limit: 150


Motherboard Tweaker/Voltage Settings:
Load Line Calibration: Level 6
CPU VCore: 1.4

Please note: Load Line Calibration keeps my voltage good while I am at load (1.416v), but when idling the voltage gets high for me (1.46v), so check this to see what works best for you.

Everything else is stock.
Edited by valkeriefire - 8/1/12 at 8:47am

I've been getting some BSODs @ 4.8ghz now. The only thing I have changed is my RAM settings. I have tried 2133mhz @ 1.5v and after several days of folding got a x124. Then I tried 1866mhz for about 12 hours @ 1.5v without issues. Then I tried 1600mhz @ 1.5v to be sure I didn't get a crash, but I got one a few hours later. My original 8-10 day streak with no crashes was 1600mhz @ 1.5v so I am curious why I am now having a problem.

My current test setup is 4.8ghz, LLC6, 1.4v CPU PLL Enabled. RAM 1600mhz @1.35v (which is the rated voltage).

UPDATE: No crashes after 12 hours at the above settings.

UPDATE: 4.8ghz, LLC6, 1.4v CPU PLL Enabled. 2133mhz, 1.5v DIMM, & 1.15v QPI/Vtt = VCCIO. BSODx124 after a night of straight folding.
Edited by valkeriefire - 8/4/12 at 1:35pm