New to overclocking CPUs, need help

Hi Madchemist83. Teacher again, be prepared for some more sleep

I wrote this up for someone else. Maybe it will help.

Overclocking Haswell i5 4690K.
I'm a school teacher, which means that I'm a good, professional, learner, just like what I want for my students. I'm trained as an Organic Chemist and spent twenty years in the computer/software/database/GIS/consulting business before retiring to become a school teacher. I do not have any real special modern knowledge. Almost everything I know about overclocking, I leaned in the last six months by doing a lot of reading on the Internet, and in the last two months by actually overclocking a couple of Pentium G3258s and an i5 4690K, and I have an i7 4790 waiting. I hope I know my limitations, and I'm learning more about this every day. I plan to introduce my students to G3258 overclocking this school year and I need to know a lot more about it than they do.

Much of what I say below I comes from many other web-sites I will cite at the end. Very little of this is original thought.

All chips are not created equal. The minor variations inherent in the manufacturing process means that chips come with a range of power and speed capabilities. Intel sets the floor, but the manufacturing variables mean that different chips will overclock differently. It is a fact of mathematics that half of all chips will be below average. On the basis of insufficient information, I would expect almost all Haswell chips to be overclockable to 4.0Ghz, but a few may not.

Haswell chips are comparatively easy to perform a simple overclock. There are only three things to pay attention to:

Multiplier. This is the number by which the 100Mhz base clock (BLCK) is multiplied to get to the actual processor speed. The G3258 starts at 32 (3.2Ghz) and the i5 4690K at 35 (3.5Ghz) 48 (4.8Ghz) is the practical limit for these chips using 'ordinary' cooling, and only the best chips can get there.

Voltage. This is the power or energy used to make the chip go. More speed requires more power requires more voltage. Something like 1.35V is as much as you would want to use for 24/7 use. Going higher is possible. From what I have read, the expected half-life of a Haswell chip is around 7 years at stock voltages, as the voltage is increased, this life is reduced. Most overclockers don't care too much because they are not planning to keep their CPU more than three or four years anyway. All of this is based on the statistics of large numbers. Each chip is an individual, and may be an outlier.

Temperature. This is the side effect of all that power. An i5 4690K is an 88W product. If you have ever touched a 75W light bulb, you know just how much energy that is. Chips are supplied with coolers to dissipate excess energy to keep them at safe temperatures under even normal extreme loads (serious gaming or number crunching), but not necessarily the special torture-testing software used for overclocking tests. To protect itself, the CPU will shut off, throttle, if the temps get too high. If you see a test that goes over 95C and keeps rising, I would stop it at once. Long term temperatures at heavy load in the upper 70s for normal use are OK, but 75 or less under all but torture-test circumstances is a good target to aim for. High temperature for extended periods will also reduce processor life.

Looking at a race car engine, Multiplier is like RPM, Voltage is HP, and temperature is pretty much the same, for the same reasons.
Testing the Chip.

Simple test. Install chip, go to Override voltage, set Vcore to 1.2V and Multiplier 46. Boot the system and see how far you get.
Quoted from this site: http://www.overclockers.com/3step-guide-to-overclock-intel-haswell/

Now, I’ll share a secret imparted by the folks at ASUS who gave several reviewers some tips on overclocking the retail stepping Haswell chips: Set Vcore to 1.20 V. Set all cores to 46x (which would be a 4.6 GHz overclock), save & reboot. If the system boots past the UEFI and either begins to load or, ideally, makes it into the OS and is stable, you have a 50th percentile or greater chip on the Haswell overclocking-ability bell curve. If it won’t at least boot there and make it into the UEFI, you probably have less than a 50th percentile chip. You can expect chips in the lower 50th percentile to top out in the 4.4-4.5 GHz range at 1.25 V.

If your chip will boot at 4.6 GHz and 1.25 V, that’s very good. It means you have at least an average chip. If it will boot at 4.6 GHz and is stable there, then you may have an above average chip. The best chips will be able to do 4.8 GHz stable at 1.25 V. Our sample did 4.8 GHz, but at 1.3 V and on a custom water loop. Using 1.3 V will likely put a chip out of the air cooling / AIO water cooling thermal envelope. Temperatures in all of these scenarios, from the dog 4.3 GHz chips up to the good 4.8 GHz chips, will always be in the ~90°C range. That’s just the nature of Haswell. With the VRM on-die, think of Haswell as Ivy Bridge plus 10° C.

So now you have some idea what to expect. If it 'fails this test, drop the multiplier down until if passes.

Voltage control.

The multiplier sets your target, voltage control sets the power level need to achieve it. There are four approaches to voltage control.

Stock. The stock Intel chip comes with internal software to manage voltage and speed. To extend life, when the chip is not being used, it idles, just like a car. When more is needed more is provided. There is a table of voltages for each speed in the CPU. I was able to overclock both G3258s and the i5 moderately, merely by increasing the multiplier, using the stock voltage management of the chip. Increasing the multiplier by 1 or 2 from stock and running stability tests and benchmarks is a good way to start. The i5 has turbo-boost, so increasing the multiplier to 39 is a good place to start there. This will not get you far, however.

Override. You tell the chip how much voltage to use all the time. That's what we did in the test. It is easy to do and is the easiest way to find out what your chip is capable of. I prefer to set my voltage to what I consider a safe level, then increase the multiplier until it fails testing, then increase the voltage in small steps until it is stable. If everything looks OK, I will try for one more multiplier increase, but the stable temperatures and voltages will probably be too high, but at least you know. My 4690K runs 4.7Ghz at 1.31V at good temperatures. It will run at 4.8Ghz and 1.373V, but the voltage is higher than I like and the benefit is small, but now I know. The drawback with override for the long term is that the CPU runs at the power no matter what the load, there is no idle.

Offset. You tell the chip how much additional voltage to add to the stock management table. A number like 0.200V is added from the 0.700V of idle ,which becomes 0.900V, to the 1.100V of full power, which becomes 1.300V. This is almost the same as override, but keeps a much lower idle voltage. Once you have your stable Override voltage, it is a simple calculation to get and equivalent Offset voltage. (HWMonitor can help you check your math by looking at the actual voltages being delivered.)

Adaptive. You tell the chip what the new top end is, and it will ramp up to that voltage when more power is required by modifying its voltage table. This gives more voltage at the top, but keeps the stock idle. To get the desired Adaptive voltage takes a bit of trial and error. There is likely a way to calculate it, but I do not yet know that secret.

It is possible, and maybe desirable, to combine Offset and Adaptive so you can tweak the top end and idle independently.

If stock is 1.100 (I think it varies for each chip, mine was a little less) and you need 1.300V for your overclock, the offset would be 0,.200V

1.100 + 0.200 = 1.300.

That will raise the top end and your idle, both by 0.200V.

If that works, I would start messing with adaptive, to try and keep the idle as low as possible.

Let us know how it goes. When you have finished, record temperatures from something like HWMonitor and run some benchmarks so you can tell later if any change has taken place.

Let us know how it goes. When you have finished, record temperatures from something like HWMonitor and run some benchmarks so you can tell later if any change has taken place.