ali, after searching google and various forums I can't find anyone else reporting this 23x problem.
I'm probably running a very simlar rig to you (check the ultima dreadnought system from ocuk, thats what I have)
Anyways, dispite being worried about ocuk not supporting my oc if I update the bios, this DPC latency problem effecting audio and causing fps to stutter in games is too major. Theres a huge amount of people with ga-x58a boards all reporting that the bios update stops the DPC spikes.
It would seem the spikes start on all these boards without the latest bios when the northbridge temp gets above a cirtain level (when the led for nb temp first lights on). It seems the older bios is doing something to cause the northbridge to restrict itself to cooldown. However this causes DPC spikes untill the bios thinks the nb is cool enought to go back to normal.
So seeming gigabyte fixed it at one point (maybe FC) for the ud3r rev2.
If you have a diffrent version or rev of a ga-x58a board then from what I have seen there are bios updates for all of them solving this common problem.
I'm about to update to the latest bios of FE myself.
I've seen some people, from before the bios fix came out, that they attached fans to the northbridge to keep it cooler, though this helped with the frequency of it happening, they still eventually would get the dpc spikes (sometimes when the nb wasnt even that hot) some others were also reporting that the actual nb temprature mesured with external sensors was lower than the bios reported. Possibly the whole problem was because of inaccurate temprature readings in the earlier bios.
I'm just about to write down all of the ocuk bios preset to set in to the FE bios after the update. I'll let you know how it goes. I really hope I don't get this 23x multiplier problem you have described. That is the same as the ocuk preset oc for 4ghz.
(note: i am updating from stock bios FA)