ADSP-BF537KBCZ-6BV or 6BX REV 0.3 Speed Issue

We are seeing a speed issue between the main ADSP-BF537KBCZ-6BV or 6BX REV 0.3 and the Micron MT48LC16M16A2P-7E IT:G SDRAM so that we are not able to run much faster than 400MHz. Therefore we cannot run at the full 600Mhz speed and we cannot run the Ethernet at 100Mb/s (runs fine at 10Mb/s). We suspect it might be because we did not use the 22 ohm series resistances at the SDRAM however, our traces are not that long either. We were wondering if you have an Blackfin expert we can communicate with to review what we have done and provide any recommendations for speed improvement.

blackifin speed adsp-bf537kbcz-6bv or 6bx rev 0.3