Have you adjusted the LDT (RAM controler) multiplyer.
The below will explane you delema being you have a default 5x LDT and are using a 220HTT your overall RAM bus speed is 1100 which is well beyond the default 1000... most MBs wont be stable beyond 1080. Keep it between 800 and 1000.
My work from another post
The LDT multiplyer (memory) relative to the HTT is a bit confusing at first.
HTT and CPU ... as it is increased the LDT would be adjusted to maintain the RAM's stability, in part, as do the RAM timings and vdimm require additional attention if you maintain a 1:1 CPU:RAM speeds.
Basically the
HTTxLDT=1000 or
200x5=1000
201-250 use an LDT of 4x
251-333 use 3x
The LDT voltage may also require increses.
A RAM divider is required when the RAM can not maintain a 1:1 ratio to the CPU when the HTT is increased beyond the RAM's ability to match the speed.
The below will explane you delema being you have a default 5x LDT and are using a 220HTT your overall RAM bus speed is 1100 which is well beyond the default 1000... most MBs wont be stable beyond 1080. Keep it between 800 and 1000.
My work from another post

The LDT multiplyer (memory) relative to the HTT is a bit confusing at first.
HTT and CPU ... as it is increased the LDT would be adjusted to maintain the RAM's stability, in part, as do the RAM timings and vdimm require additional attention if you maintain a 1:1 CPU:RAM speeds.
Basically the
HTTxLDT=1000 or
200x5=1000
201-250 use an LDT of 4x
251-333 use 3x
The LDT voltage may also require increses.
A RAM divider is required when the RAM can not maintain a 1:1 ratio to the CPU when the HTT is increased beyond the RAM's ability to match the speed.