It could be noise on the power supply. Perhaps it's some 60 cycle hum on an upper harmonic? Do you have an uninterruptible power supply you can run it on?
If wacom is keeping its record of defective products (usb coming lose in intuos 4, and apparently power block issues in cintiq24hd), that may not be that bad of a deal getting the older gen...
yeah I agree... When it comes to tools, I would rather be amputated at the knees then live with the gnawing pain of compromise. ( because I went cheap. which I have with the graphire I have suffered with for the past 8? years ) On the other hand, prices have dropped for everything over the past twenty years ( even Thailand…