I bought i5-4670 and Asus H87-pro 2 weeks ago and everything worked fine (3800 MHz turbo frequency) till I decided to update the bios.
Now multiplier won't go over 36, but everything is set properly (Turbo on, MCE enabled, information about target CPU and cache speed 3800 MHz, etc... ), also CPU-z is showing 8-38 multiplier range, but in any app that uses CPU 100% (rendering, linx) frequency is 3600 MHz (multiplier is stuck on 36).
Is there any setting that can make speed right?
With a locked multiplier the overclocking can only be done by the Bclk and the 38 is for the turbo boost which will only boost one core anyway so when the turbo kicks in it really isn't doing much and its only for a short time.
You may want to contact Asus tech support to see if there is anything that they can do because other than reloading the bios or a different bios there isn't much that you can do.
In the bios try loading optimized defaults.