There exists no standard way to report temperatures and unfortunately most tools take several months to fully support new hardware. Discrepancies are more common than accuracy.
Intel has not changed anything core temperature related with any Core i processor since the first one was released in November 2008. The most recent versions of Core Temp and RealTemp have no problem reading Ivy Bridge CPUs correctly.
The temperature that Asus Probe reports comes from a different sensor than what RealTemp and Core Temp reports. As mentioned, Ivy Bridge runs hot and the peak core temperature when fully loaded with a stress testing program is going to be significantly higher than the temperature that Asus Probe reports.
Enjoy your new CPU and don't worry about your core temperature unless your CPU starts thermal throttling which doesn't start until the core temperature hits approximately 100C. Intel designs their CPUs so they can run very reliable at very high core temperatures. No worries.