I have tried installing Ghost on two different computers. On a 3 year old Intel Q9450 and on a brand new AMD A8-3850 quad-core.
When backing up on the Intel with High compression Ghost uses all four kernels 100%. When backing up on the new AMD it uses 1 core 100% (or 4 cores 25%) and I achieve a much lower backupspeed.
Can it really be that Ghost is not able to use all four cores on a new AMD CPU?