Lenovo ThinkCentre with i5 4590T
Am running Xmrig on an intel 4590T with 8Gb of ram solar powered miner. Currently I can only get one core running, so am using 25% of cpu power. Tried adding --threads=2 to command line but had no effect. 

Have searched online but not found any real answer, other than adding more threads.

Is the cpu just not up to the job? Or do I need more ram? 