We then retested at tighter memory timings. We used the following

We see that the sweet-spot for the memory modules seem to be around 2.8v. The
clock speed suffered a huge drop when going over to this setting, from the previous
297MHz attained to the 257MHz with this setting.

After some testing, we found that it is the TRCD (RAS to CAS Delay) setting
that is limiting the memory so we set this back to “4” and tested
at the following settings:

At this setting, we managed to get the memory modules up to 287MHz.