Im overclocking a 920 d. So far i have it at 3.4. The temps are still really low but its getting unstable. i want to know what i can do to stabilize it.
Try to install better memory DIMM with lower latencies and heat sinks.
Then raise the voltage as said before.
I had an interesting experience where just changing the memory (CL3 from a not known manufacturer) to a CL2 DIMMs with heat sinks from Patriot led me on OC from a max 3.30GHz to a new max 3.75GHz, stable, with a Pentium 530!