Your pipes are locked via the die. I have the same card as you. Which brand is yours? If you have the r480 core you should be able to overclock it pretty well, and also flash to a modified x850xt(pe) bios. If you have the r423, you won't be able to OC the core as well, but you should be able to flash to a x800xt(pe) modified bios. Note that flashing to either of these will not unlock to any more pipelines, but will raise performance.