does voltage affect CAS stability?

Like I don't think my memory is totally stable at cas 2.0 and vdimm 2.63V. If I increase vdimm, will this give me more stability??

yes

Most of the time increasing the vdimm will increase stability, but I have heard there are some memory sticks out there that are not affected (haven't come accross any yet though), but increasing the voltage, as long as its within reason should not hurt your ram, so why not give it a try and see if it helps it, just my 2 cents.