what is VTT on PSU

hardware doctor says my VTT rating is too high (the little danger thing pops up) because its at 1.66 and not the normal 1.55ish area. would this cause any problems in a system or not really. all other voltages 3.3, 5 and 12 are perfect.

PSU is Antec 550w

I don't know what Vtt is, but I wouldn't trust MBM or any other hardware monitor program without first verifying the readings with a meter because with one mobo MBM read the +12V rail 20% too low, and SpeedFan said that it bounced between 6-8V every second. If Vtt is the CPU core voltage, the only way to measure it with a meter is by poking the pins and metal tabs of the MOSFETs, but wedge cardboard or wood between their pins to make shorts less likely if the meter probe slips.

VTT is on the MB, not the PSU.

It is 1/2 VDIMM.