HI

Haswell overclocked to 4.6 FSX runs fine but when ovc to 4.8 it crashes at startup. Any ideas/help? Win8 runs fine at 4.8 and no heating problems with my corsair H90.

Many thanks

 

Just a guess. Overclock Stable at 4.6 not at 4.8? :excl:

Most of the 4770K's are not capable of overclocking that high.  I have yet to get it stable even at 4.6 and currently sitting at 4.2.  I have followed ASUS overclocking guides to the "T" and still get crashes.  It is not as easy to overclock as the Sandy Bridge. 

 

Best regards,

Jim

Did you test your stablity using software like Prime95 - http://www.mersenne.org/freesoft/, direct link http://download.mersenne.ca/gimps/p95v279.win64.zip

 

Try running the blend test for at least 30 minutes and see if there are no errors. If there are - you have your answer. As Jim mentioned it's even highly doubtful the 4.6GHz is stable. 

I'll start by lowering the multiplier to 42x and play around with the CPU and VTT voltages until it's "prime stable" for at least 30 minutes.

 

System boot is no indication of stability. Only putting it under high pressure (like Prime95 does) is. It's fairly common for an OC'd system to run perfectly under normal working conditions (office application, browsing, etc.) but crashing when under heavy load like playing games. Only tedious, using small steps, overclocking and load testing will give stability. It's also important to realistically lower your expectations and not compromise stability over performance improvement.

 

Hope I helped,

Łukasz

No I didn't run Prime95 etc. but had not a single crash with 4.6. I was hoping for some hints alike bus (100) or memory speed(2400). Anyway it would make only ~3 fps difference or so, hence I won't investigate any further.

Well you didn't provide any information regarding your settings - voltages, frequencies, multipliers, RAM settings etc. So it's hard to give any specific advice. I suppose If you managed to get it to 4.6 you know the general idea of overclocking. Basic advice if it's crashing is to bump the voltage a little (like 0.05V) and prime test for at least 30 minutes. If it fails bump it a little more, until it passes the test. Remember it's not just the CPU voltage that matters. RAM voltage and VTT (memory controller) are also important. In the end run a prime test for a couple of hours to be 100% sure everything is OK.

agree with above post, that means you have stable 4.6 and 4.8 just need to be "stabilized" - adjusting the settings / voltages