Overclocking clover installation

Hi all,

Not sure if it is the right place to post this thread, but if no, would be appreciated if the moderators can move it where it belong.
I have managed to install Yosemite on an SSD and now that everything is stable and running fine, I would like to overclock my system (as per my mavericks system which was also overclocked).
I have a Z97X-UD5H + i7 4790K + 16GB
XMP is enabled in the UEFI bios, XMP=Yes is set in clover config.plist and using various diagnostic tools, it shows that the memory is running at 2133Mhz as opposed to the 1600Mhz.
The processor is 4Ghz, the default setting. It the bios it is possible to select predefined value for teh cpu speed via a menu. I selected 4.8Ghz which is the highest predefined settings. The doc does not really say what this setting means (I mean apart from changing the cpu speed, I can find any info regarding whether or not the memory speed is also adjusted, etc..)
When I restart the system, clover boots the SSD drive, displayed the apple logo and there is a progression bar which normally goes 1/3 before the desktop is displayed. On the overclocked system, after 10% of loading, the system resets.
My question is: do you need to rebuild the cache when overclocking? If the cache has to be rebuilt then I prefer starting with that rather than fiddling the settings in the bios.
Thanks

Moved to Overclocking

A predefined 4.8Ghz overclock setting is very unlikely to work. OSX is resetting because the overclock is unstable. Nothing wrong with the hackintosh system itself.

Do some research on how to properly overclock.

The basic system is:

CPU Ghz = Base clock * multiplier. By stock the 4790K runs at 100mhz bclk * 40 multiplier which results in 4000mhz which is 4Ghz.

Start at the stock 40 multiplier and change by +1 until the system fails a CPU stress test. I usually use windows programs like IntelBurnTest for stress testing but I think Geekbench for Mac has a stress test function. Reminder that increasing the multiplier by one increases the CPU Ghz by 0.1Ghz.

When your system isn't stable, increase VCore voltage by 0.025V. The maximum voltage for Haswell is 1.4V but you're usually limited by cooling.

If are still using the stock cooler then don't even try overclocking. Not on an i7.

Here's a good resource for finding out what kind of overclock you can expect depending on the cooling you use. The average on aftermarket air cooling is 4.6Ghz. http://hwbot.org/hardware/processor/core_i7_4790k/