Overclocking with i5 4690k and a 500w evga psu

It varies, so we can only cite what is typical for the i5 4690K, which is about 4.6GHz +/- 200MHz. Veteran overclockers know this, so your question suggests that you're not experienced. We advise that you study the topic (links below) before you overclock, so you don't risk damaging your hardware.

Overclocking is always limited by two factors; voltage and temperature. No two processors are identical; each is unique in voltage tolerance, thermal behavior and overclocking potential, which is often referred to as the "silicon lottery". As Core speed (MHz) is increased, Core voltage (Vcore) must also be increased to maintain stability. This increases Power consumption (Watts) which increases Core temperatures. Overclocked processors at higher Vcore might run more than 50% above rated TDP (Thermal Design Power), so just as darkbreeze pointed out, high TDP air or liquid cooling is crucial.

A Cryorig H7 would be a good choice - https://www.newegg.com/Product/Product.aspx?Item=13C-000U-00005

Overclocking should not be attempted with Vcore settings in “Auto” because BIOS will apply significantly more voltage than is necessary to maintain stability, which increases Power and heat. We know that excessive heat over time damages electronics, so even when using manual Vcore settings, excessive Vcore and Core temperature may result in accelerated "Electromigration" - https://www.google.com/?gws_rd=ssl#q=Electromigration

This prematurely erodes the traces and junctions within the processor's layers and nano-circuits, which will eventually result in blue-screen crashes that become increasingly frequent over time. As a rule, CPU's are more susceptible to Electromigration with each Die-shrink. However, the most notable exception is Intel's 14 nanometer Microarchitecture, where advances in FinFET transistor technology have improved voltage tolerance.

Here's the maximum recommended Core voltages per Microarchitecture from 14 to 65 nanometers since 2006:

With high-end cooling you might reach the Vcore limit before 85°C. With low-end cooling you’ll reach 85°C before the Vcore limit. Regardless, whichever limit you reach first is where you should stop. Throttle temperature (Tj Max) for your Devil's Canyon 4690K is 100°C. However, since cooler is better for ultimate stability, performance and longevity, it's prudent to observe a reasonable thermal margin below Tj Max.

Here's the nominal operating range for Core temperature:

Core temperatures above 85°C are not recommended.

Core temperatures below 80°C are ideal.

Remember to keep overclocking in perspective. For example, the difference between 4.5 GHz and 4.6 Ghz is less than 2.3%, which has no noticeable impact on overall system performance. It simply isn’t worth pushing your processor beyond recommended Core voltage and Core temperature limits just to squeeze out another 100 MHz.

I recommend that you carefully read these guides:

Beginners guide to overclocking your CPU - http://www.tomshardware.com/faq/id-3761568/beginners-guide-overclocking-cpu-explicit-testing-guidelines.html

Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

CT