Overclocking the X58, a practical guide

Disclaimer: For the sake of clarity. Overclocking any piece of hardware should be considered harmful before even considering the benefits which the process will yield. Some hardware manufacturers do not warrant the abuse of hardware. I am not responsible for how far any PC owner chooses to push their hardware if inspired to reference this guide. This guide is a work in progress and I will be updating it when new, legitimate, information creeps into my way.

Let the fun begin!

Step 1: Understanding the X58 chipset.

You only need one image to get started and then a little bit of intuition to start understanding it.



This is a block diagram, and it shows the relation between the different parts of X58 motherboards. Not all motherboards are the same, and not all manufacturers will use the same terminology to describe every changable clock. The important part is that all X58 boards can be understood by applying the settings in a given bios with this block diagram.

Important Note Understanding the block diagram is easier when you compare it to the bios.

That may be a stretch for some, but it will make more sense later on.

Step 2: Write up a bios template.

Do it. Go to the bios, find the OC tab, and write down those settings on a PDA or notebook or even... paper :O

Step 3: Understanding the bios template.

Remember that block diagram from Step 1? Keep it handy

Universal terms

• BCLK- Short for Base CLocK. This is the base frequency at which your CPU will drive the rest of the PC. The limiting factors in max BCLK will be the cpu itself (luck of the draw) and the motherboard (luck of the draw/quality control). (BCLK)CPU Multi = CPU Frequency. For 32nm Westmere chips it is best to overclock with chips that have high multipliers as max BCLK is low with these chips. At and beyond 200 BCLK the qpi/vtt voltage required to post become too high to be considered safe to overclock for over 24 hours.
• DRAM- Main Memory, ur DDR3, the triple channel goodness, whatever... (BCLK)Memory Multipler = DRAM frequency.
• Uncore- This is in the block diagram but not written. Uncore is a frequency that the CPU handles everything from the north bridge to the south bridge. Uncore must be at least 2x as great as the memory frequency. This can be an issue if your CPU/motherboard can not handle an insanely high uncore, so for the record a memory overclock will affect the uncore stability. An overclock can get a special edge by pushing the uncore beyond 2(memory multi). If you have room to OC it then go for it. SPECIAL NOTE there are substancial findings to suggest the average overclocker can increase their uncore multi by 1 and may achieve higher system stability even at mild OCs. This can even reduce voltage at higher OCs and is a MUST to consider for MAX OC.
• QPI- Quick Path Interface is the memory I/O for the CPU. With CPUs like the i7 920 the low QPI rating can interfere with MAX OC. Only a few motherboards have the options to circumvent this barrier.
• IOH- North Bridge, affected directly by Uncore
• ICH- South Bridge, less affected by Uncore than the North Bridge
• CPU Multiplier- Explained in the BCLK bullet as a factor of overall CPU frequency the CPU multiplier represents the CPU's proportional speed to the BCLK. For a x21 CPU multiplier you would take the BCLK frequency and that's how many cycles the CPU completes before it is addressed by the BCLK.

These universal terms are the bread and butter of your overclock. You want to tune your boards to acheive overclocks in these domains. Depending on the benchmark or application there are a number of ways to set the BCLK/DRAM/Uncore/QPI for increased performance.

Common voltages (45nm Bloomfield)

• VCore - directly related to the CPU frequency. Chances are if the cpu frequency doesn't change then this does not need to be changed. "Safe" for overclocking voltages range from 1.0-1.53V (intel spec).
• QPI voltage/CPU vtt- related to any change in memory frequency. If you change the BCLK, the memory frequency will change. This voltage also affects the uncore stability indirectly. "Safe" for overclocking voltages range from 1.1-1.4V (intel spec).
• IOH Core Voltage- Different than IOH PLL, and more important! This observation will be explained later. The catcher.
• ICH Core Voltage- Not important.
• Core pll- Signal strength of the CPU. At higher core voltages/frequencies the Core pll can be reduced below spec to enhance stability.
• IOH pll- Think of this like the catcher's pitching strength. The catcher (IOH) needs to catch, not pitch so much.
• QPI pll- The pitcher's pitch! Some motherboards tie this pll voltage to be proportionate with the cpu pll, but that's stupid. If your motherboard doesn't support this voltage then by all means don't try to increase the cpu pll to achieve results. When you are reaching (within .5GHz) the physical limit of the QPI clock for your chip this is usually a culprit for stability. At a max of 1.5V (DON'T GO HIGHER) some stubborn chips and boards can reach high BCLK OCs. The IOH Core Voltage needs to be = to the QPI pll voltage for best results. The two voltages should be the same at stock 1.1V or something like that. If they are not the same then do not change them because your bios probably has them named differently.

Fun fact! Believe it or not VCore/CPU vtt has less to do with heat output than the frequency of the clocks in the CPU itself. When you see CPU cooler review sites testing a 3.6GHz core i7 @ 1.5V on the core the heat is not even close to an i7 4.2GHz @ 1.24V on the core. This observation is only applicable to 45nm bloomfield. 32nm Westmere chips heat up proportionally to both frequency and voltage.

Common voltages (32nm Westmere)

• VCore - directly related to the CPU frequency. Chances are if the cpu frequency doesn't change then this does not need to be changed. "Safe" for overclocking voltages range from 0.9-1.4V (intel spec).
• QPI voltage/CPU vtt- Any change in CPU frequency for 32nm chips. If you change the BCLK, the memory frequency will change. This voltage also affects the uncore stability indirectly. "Safe" for overclocking voltages range from 1.1-1.4V (intel spec). ***CAUTION*** Raising the vtt beyond 1.35V has shown to damage 32nm based chips. This observation was made by a number of overclockers, and the information is to be used as a measure of caution. If you're approaching the intel spec MAX for this voltage then you are getting dangerously close to causing damage. Approaching the maximum or going beyond would not be advised unless someone is benching with sub-zero cooling for some time under 24 hours.
• IOH Core Voltage- Different than IOH PLL, and more important! This observation will be explained later. The catcher.
• ICH Core Voltage- Not important.
• Core pll- Signal strength of the CPU. At higher core voltages/frequencies the Core pll can be reduced below spec to enhance stability.
• IOH pll- Think of this like the catcher's pitching strength. The catcher (IOH) needs to catch, not pitch so much.
• QPI pll- The pitcher's pitch! When you are reaching (within .5GHz) the physical limit of the QPI clock for your chip this is usually a culprit for stability. At a max of 1.5V (DON'T GO HIGHER) some stubborn chips and boards can reach high BCLK OCs. The IOH Core Voltage needs to be = to the QPI pll voltage for best results. The two voltages should be the same at stock 1.1V or something like that. If they are not the same then do not change them because your bios probably has them named differently.
• CPU pll- This voltage is overlooked for 45nm chips mostly because it is not an issue when overclocking. For 32nm chips the maximum voltage is 2V, and slight increases above the automatic setting of 1.8V may increase stability.

Step 4: Trial and Error

This is something a lot of us hate, but have to deal with. When going for extreme OCs you will go mad before ever getting anywhere. Double check the info in this thread with what you understand. Compare your bios template to the block diagram. Get an idea of which parts are stressed, and what voltages may need adjusting. Most importantly eliminate variables! Narrow down the cause of your instability with scrutiny.

Step 5: Testing

A number of people have a number of views of what is stable. I like to throw a fruit basket of tests at my PC to test stability. OCCT will find a bad memory overclock in no time. Prime 95 small FFT will crash most unstable cores in 20 min or less. Vantage will test your Uncore stability as it relies heavily on IOH bandwidth. Folding@home and BIONC clients don't make as much heat (unless you give it 100% CPU control) but if your results are proving to be erronious then you are doing it(the OC) wrong. Sometimes this will crash your machine, sometimes it won't, but massive errors = instability. Video games are amazing for testing overclocks! Believe it or not some games will just bluescreen you in a bad OC, so while you're beating your brain over this OCing thing... have some fun

Step 6: Thank me! No really thank yourself. If you've gotten this far it means you didn't have someone punch in their voltages or motherboard settings for you and you understand the failure mechanisms of YOUR hardware more than anyone else.

This concludes the body of my practical guide. I hope anyone who reads this will walk around TPU with a greater understanding of their X58 workstations.

Reserved for future notes/motherboard specific settings & tweaks.

FAQs

Q. Will temperature affect the stability of my overclock?
A. Yes for 32nm Westmere AND not always for 45nm bloomfield. There is nothing saying that water cooling vs high end air cooling yields any better results with 45nm bloomfield processors durring a bench session. Extreme cooling will yield better OC results on extreme CPU frequencies (5GHz+) in a bench session. I can say with certainty that high temperatures in the area of 80-90C will show their effect on CPU longevity before causing stability issues in a bench session. CPU longevity would mean that if you returned your cpu to stock then it may perform normally or less as well as the day you bought the CPU.

Q. What are the different ways of achieving an overclock?
A. There's two ways to overclock every part of the x58. You can either increase the BCLK or you can increase the frequency multiplier of a domain. Something to consider when overclocking memory is that once you increase the memory multiplier you're forced to increase the uncore and QPI.

Q. I'm having problems setting performance goals. What are some examples of overclocks I can achieve with a i7 920.
A. It's very important to set goals, and even if the goals aren't your own it's OK. Please understand that voltages change based on hardware, but approach voltages with less fear and an appropriate level of respect for your hardware. Fearing errors/hardlocks/bluescreens will only make OCing harder, defeat the purpose of Step 4, and make you more reliant on people who may be too wreckless.

Acceptable performance goals for 24/7 use & Benching (45nm Bloomfield):

• 24/7: stock CPU, high memory multi- BCLK 133, CPU Multi x21, Memory Multi x12, Uncore Multi x24-x27, QPI AUTO. This will require little to no core voltage change, but you will most likely have to increase the QPI(vtt) voltage, and the memory multiplier is high so uncore will also be very high for your CPU. This is memory overclocking for a target of 1596MHz so your computer will feel a little more snappy, but nothing quite like what a core OC would do.
• 24/7: Mid range CPU and medium/high memory multi- BCLK 166, CPU Multi x21, Memory Multi x10, Uncore Multi x20-x23, QPI AUTO. Less stress on the QPI(vtt) and uncore. May be easier/produce less heat than the settings above. Most D0 stepping can achieve this using stock VCore, but keep in mind not ALL can. Target CPU 3.48GHz, Target memory 1660MHz.
• 24/7: The "magic" BCLK OC- BCLK 200, CPU Multi x13-x21, Memory Multi x8, Uncore Multi x16-x19, QPI AUTO. This is my favorite setting for BCLK because it makes for an EASY 1600MHz ram OC, and you can clock your CPU from below stock to 4.2GHz. You will have to tune this but it is so much easier on the memory OC. Some chips handle 200 BCLK like they were made for it while others (mainly seen in the first steppings for x58 i7s) fail miserably and require LOADS of voltage. Raising the BCLK is preffered for memory overclocking because it allows you to keep low multipliers which is better for stability!
• Bench OCs: Anything over 200 BCLK and using a mixture of BCLK >133 and CPU Multipliers >x30 are considered to be bench OCs. They require a lot of tuning and I can't offer too much advice here because while I have done 226x21 there aren't the words to describe my journey to that point. When considering the three above 24/7 OCs make sure you take note of the multipliers and which parts are weak in your i7. If your i7 can't handle high memory multipliers then you know for high memory OCs you will have to use more BCLK than memory multiplier. Simply, the three above OCs, if learned, will offer a lot of insight into benching.

Q. I have questions, you aren't around, and you have a foul smell. Where can I get other opinions about my OC?
A. My odor is a glandular problem... i7 Overclocking and Feedback


Good Guides/Threads from around the webs for General Purpose X58 Overclocking & Motherboard Specific X58 Overclocking

• How to Overclock the i7 a Guide by shansmi of EVGA forums - Recommended by Live or Die
• Nehalem 101 by Saaya of XtremeSystems.com forums - Recommended by Shevanel
• Max Base Clock Strategy Guide by linuxrouter of EVGA forums
• Motherboard Specific Guide - Gigabyte X58 Extreme by eva2000 of i4memory.com
• Motherboard Specific Guide - DFI X58 T3eh8 by eva2000 of i4memory.com
• Motherboard Specific Guide - ASUS Rampage II Extreme by eva2000 of i4memory.com
• Motherboard Specific Guide - ASUS P6T by eva2000 of i4memory.com

User written guides by miahallen! Priceless info! x58, LGA1156, LGA1155

• 3 Step Overclocking Guide- Bloomfield & Gulftown
• 3 Step Overclocking Guide- Lynnfield
• 3 Step Overclocking Guide- Clarkdale
• 3 Step Overclocking Guide- Sandy Bridge

Updated Q&A section with "Overclocking Goals" as of 9:21 this evening.

Updated for 32nm Westmere based processors.

updated with new user submitted guides in post two, and fixed the deadlink in post #1!