Ivy Brige BCLK OC

Tips for BCLK OC:

Increase VTT Voltage for BCLK OC over 110 in some cases

Drop temp to -60 to -80C, and you can start with 105 or 110.

If you are using the iGPU you will get stuck at around 111MHz

If you are using a PCI-E Gen3 card, the 7000 series have some issue with PCI-E 3.0 and BCLK and cold, so you might want to change them to PCI-E 2.0

BCLK change will require restarts, however in Windows it is okay to do a 3-5% raise in BCLK without restart

Post code 72 is usually BCLK related if you are pushing the BCLK

Your initial BCLK change will require a full reset of the PCH to properly initialize a BCLK change, however there is a 3-5% margin where there isn’t a needed restart after that. With some BIOSes changing from 108-111 BCLK might not require a restart if you go in 1-2MHz increments.

How to get rid of the Cold Bug:

BCLK: Most CPUs do not have cold bugs; if they do then they also have a cold boot bug. The best way to proceed to maximize the cold boot bug is by first increasing the BCLK over 102-104mhz. When you OC with LN2 you have to increase the BCLK, and when you increase the BCLK you will also increase the CPU frequency which allows users to get above 6.3 GHz as the maximum Ivy Bridge multiplier is 63X which is readily exhausted. With my 3570K I increase BLCK to as little as 4 MHz and was able to change my cold bug from -120c to -150C and my cold boot bug from -70C to -140C. I would start with 106mhz BLCk and work up from there!

CPU PLL: This voltage can be changed, now I have tested from 1.4v to 2.2v in 0.05v increments and found that CPU PLL had no positive effect on CB or CBB from 1.4v to 1.8v, and had a slight negative effect above 1.8v. The fact that it had a negative effect above 1.8v means that it has some effect, and that perhaps most CPUs are optimized for 1.8v, however if your isn’t it could be nice to find out by testing every voltage in 0.05v increments. Through deductive reasoning we can think that this voltage might help.

A note on odd CB/CBB Experience:

I will find my best settings, and then I will go for something and then restart. If I crash in windows, then I hit restart button on the board very quickly, and then I can proceed to restart without CBB. However some CPUs that have no CB, might have a CBB, and for some reason they will only trigger the CBB if the board has powered the CPU down for longer than a few seconds, so if you restart quickly enough you should be fine. This means that I can go into BIOS and change BCLK to 112 from 110, go through a restart (if needed as some BIOSes won’t restart for only 2 MHz) and then I can have no CBB! But if I restart and wait like 30 seconds I might then have a CBB. With a 3570K I had a bad CBB or -70C and a bad CB of -150 but that was with 110BCLK, now if I hit the CB and crashed because of CB then I would trigger the -70C CB, however if I crashed because of OC or instability then I would not trigger the -70C CBB, instead my CBB would be -140C.

LN2 OCing Voltages:

Voltages to increase:

Many users just increase vcore, however very high vcore like over 1.9v might not be always better, as the vcore will increase the die temperature, and many cases the die temperature is more pertinent to the CPU frequency. Some users also like to increase the VTT and System Agent (IMC) to help increase the BLCK and memory stability, it is hard to find clear cut benefits to doing this, however it can help with certain clocks and CPU. You should use high Vcore for max clocks, but many CPUs do not like over 1.83-1.85v for 2D and 3D benchmarks because the high voltage increases the temperature of the CPU more. Ivy cares more for temperature than it does for voltage.

Voltages to decrease:
You should always try to decrease the CPU PLL and perhaps the VCCIO(VTT) and VCCSA(IMC) if not only to help decrease temperatures even more if you don’t need them for BCLK and Memory stability. CPU PLL Might help CB by affecting the temperature of the die so that the CPU can run at a colder temperature.

Power Consumption under LN2:

If you take a look here we see the power draw (12v current monitor on the 8 pin connector) when running wprime 1024 on a 3570K on a G1 Sniper M3, what is amazing about this shot is that 234W is being provided to the CPU VRM through a 4-pin power connector powering a 6 phase VRM (identical CPU phase quality as UD3H and UD5H and Sniper 3). The CPU is at 6.1 GHz. This just proves there is no need for huge power delivery, like there is no need for 24 phases on these boards.

Page 1 - Introduction	Page 6 - Step 3: OC-Profiles
Page 2 - Ivy Bridge Basics	Page 7 - Ivy Bridge and LN2
Page 3 - 22 Nanometer and Maths	Page 8 - Ivy Bridge LN2 Memory Overclocking
Page 4 - Step 1: Ivy Bridge CPU Overclocking	Page 9 - Ivy Bridge BCLK Overclocking
Page 5 - Step 2: Ivy Bridge Memory Overclocking

The original article comes from Steven Bassiri also known as sin0082. We asked sin0082 if we can publish his article and he said yes. Furhtermore I (Marc "rewarder" Büchel) translated it to German. sin0082 also has his own website: SinHardware where you can find quite a few very interesting articles.

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