Today I've took the liberty to perform some current measurements on the P2Eval, while on idle, and then when programming and running the prime numbers calculator program (code available inside the attached zip file - thanks to ersmith for suggesting some improvements, BTW). As you can see, in the photo attached, the board was being supplied via its "PC USB" connector. The device on the right is the ITUSB1, a USB test switch that also has the capability of measuring current, besides connecting and disconnecting VBUS and data lines.
The graph is very telling. The vertical axis is expressed in mA, while the horizontal one is expressed in units of 0.1s. The P2Eval is attached at around 4s, consuming 50mA on average, until it is programmed. After programming, it consumes just under 350mA, even if the program is not calculating primes and just waiting for user input. Strangely, the P2 seems to demand a bit less current when the program is active calculating small numbers (from second 24 to 80).
As far as the voltages are concerned, I've measured 4.75V at the type B connector on the ITUSB1, 4.60V at the type A connector on the same board, and 4.27V at the 5V rail on the P2 Eval. Of course most of the voltage drop happens on the cables, but a drop of 156.2mV on the ITUSB1 alone is still considerable (at around 300mA).
Anyway, I'm do the same tests when I get the new P2 Eval. It would be interesting to do a comparison between the two. On a side note, I should mention that the P2 Eval continues to consume the same amount of current when only the data lines are switched off (61mA when idle or around 300mA when programmed and running). The current eventually drops to about 6mA after a few minutes, which still violates the USB spec for suspend. It is not an important aspect, IMHO, anyway.
Kind regards, Samuel Lourenço