is not good idea to use saturated colour texture map for displacement, which should use greyscale map specifically prepared for displacement.  this is advanced issue.  however, if vendor sold you  product in which both bump and displacement maps used on same posersurface, may be some reason known only to said vendor.  it takes time to learn all these things, hence be patient.

if both bump and displacement are present, try temporarily disconnecting displacement map and see if it renders o.k., and if it renders faster.