the timings are what they are. what are the timings of the RAM at stock, if the timings are lower now then you have an issue.
when you made the memory run faster you changed the timings accordingly, they are linked to each other as the timings are measured in clock speed, change the clock speed and you MUST change the CAS timings.
higher freq MEANS higher timings. always.
take any stick and overclock it the timings MUST rise accordingly.
get the fastest stick you can ge at stock. the lower the timings at stock the lower the timings when overclocked, but the OC timings MUST always be higher than stock.
its like a law somewhere