Not sure what you are looking at to see 860, prob something showing true freq in which case yes it would be doubled as it's DDR (Double data rate) so your DRAM is actually at 1720. SOunds like a multiplier turned up, is the CPU OCed? At 1720 the CPU should be able to handle it - can try raising the DRAM voltage + 0.05 and the CPU/NB voltage about the same