Author: Adam Wilson
So you’ve picked up a Intel Z77 board and an Ivy Bridge unlocked CPU and you want to know how to make your CPU perform better. In this guide I’ll be detailing how to overclock your CPU with both offset and fixed voltage methods, along with ideal board/BIOS parameters for your new clock to remain stable. So are you ready to overclock? Let’s go!
Disclaimer: This guide is meant as an information resource and not an instruction set for overclocking a CPU. Overclocking in many cases voids the warranty on your product. If any damage arises from you following this resource, ThinkComputers.org cannot be held accountable. We did not change your settings, you did.
Before you start, there are a few pieces of software I’d recommend you get to both monitor and test your new overclock. There are many available, but the suites I use are:
Prime 95: A rugged stress test that puts your CPU to full load. Prime95 is for extended stability testing. Testing with Prime95 is not recommended if you’re not going to let it run for a recommended 8 hours plus.
IntelBurnTest: IBT is a suite designed to REALLY stress your CPU over short periods. It puts your CPU to full load and then continues to push it. It runs 10 tests that all complete in a relatively short amount of time. I have seen temps rocket past my Prime95 max temps in a matter of seconds. Do NOT run IntelBurnTest on a high overclock without testing PROGRESSIVE overclocks first. It can push your CPU over its Thermal Maximum and you will risk damaging your chip.
CPU-Z: CPU-Z will give you detailed information on your installed processor, including the thing we need to monitor the most: voltage.
RealTemp 3.7: A good temperature monitor that will detail min/max/current temperatures, and the “distance” to your CPU’s thermal maximum. There are other alternatives, but RealTemp is mine, and many others, favorite.
An Introduction to Overclocking Ivy Bridge:
Every processor has a FSB (Front-Side Bus) speed, this is also known as BCLK. Ivy Bridge’s FSB is 100mhz.
Each chip works on a multiplier. As this guide is written from the perspective of the 3770k and 3570k, the maximum multiplier is 63x. What this means is that you take your 100mhz FSB and multiply it to give you a clock speed.
The 3570k’s base clock speed is 3.4ghz, or 3400mhz. So this is a 34x multiplier on the 100mhz FSB.
In theory, Ivy Bridges theoretical maximum clock speed under air or water is 6.3ghz (100MHZ FSB x 63x multipler.) It’s unlikely you’ll achieve this though, as temperatures are a major factor in your CPU’s performance and lifespan.
As I’m sure you know, hot = bad. Ivy Bridges thermal maximum (as in, the temperature it can hit before it shuts off to save itself) is 105C. That isn’t what you should aim for, though. If your overclock hits 90c full load on Prime95 at any point over the duration, reduce the voltage or reduce the multiplier.
Terms & Maximums
Aside from temperatures, there are other maximum settings that you should not go over in order to prevent chip degradation or damage. Here are some terms you’ll need to know and understand if you want to achieve a nice overclock.
DO NOT TOUCH BCLK (FSB) SETTINGS UNLESS YOU HAVE ACCESS TO LIQUID NITROGEN OR LIQUID HELIUM.
VCC – AKA VCore: Intel recommends you do not exceed 1.52 volts. So don’t. This is the voltage your CPU receives directly. If you’re overclocking on air or water, I wouldn’t recommend you go over 1.45v, as this is where temperatures can get pretty high.
VCCPLL – AKA CPU PLL: Stands for Phase-Locked Loop, this is the voltage of the internal clock on your CPU. Reducing PLL can have a nice effect on temperatures but can affect overclock stability. If you’re hitting the max on your VCC, you can try raising the the VCCPLL. Do not go over 1.89v. Reducing the VCCPLL can have a significant affect on your overclock performance if you drop too low. Don’t go lower than 1.709v.
VCCIO – AKA QPI/VTT: This is the voltage received by the integrated memory controller on the CPU. It can help when stabilizing high memory overclocks. You shouldn’t need to touch it for overclocking your CPU. There are some instances where you may need to, and I’ll list them later.
VCCSA – AKA IMC/System Agent: You shouldn’t touch this setting unless you’re extremely confident with overclocking . That said, adjusting this voltage helps with high memory overclocks and/or BCLK overclocks. Max is 0.971v.
DRAM Voltage – AKA DDR Voltage: This is the voltage your RAM receives. Intel recommend a maximum of 1.5v, but there are numerous 1.65 kits on the market, and if you’re overclocking RAM then chances are you’ll need to increase this. Do not exceed 1.65v.
VGFXVID – AKA IGPU or IGFX Voltage: Voltage for the integrated graphics controller. Not needed for overclocking. Max is 1.52v, though.
Exceeding these maximum values can and in many cases will damage your CPU irreparably, so be careful.
LLC: LLC stands for Load-Line Calibration. In short, when a CPU reaches full or loads, the VCC tends to drop down. If the VCC drops too far, this can lead to stability issues including BSODs and freezes. LLC was made to combat this. Each board is different, but my ASRock is set up so that Level 1 gives you the most compensation for Vdroop, and level 5 the least. I found that using Level 1 causes my voltage to spike upwards, so I tend to go with Level 2 or 3. What you’re trying to achieve is as close to the same voltage under load in Windows (use CPU-Z to check) as it reports in your BIOS when you’re configuring things.