Refer to the PDF data sheet for device specific package drawings
Keep the crystal and its load capacitors close to the USB PHY pins, XI and XO (see Figure 8-25). Note that frequencies from power sources or large capacitors can cause modulations within the clock and should not be placed near the crystal. In these instances, errors such as dropped packets occur. A placeholder for a resistor, in parallel with the crystal, can be incorporated in the design to assist oscillator startup.
Power is proportional to the current squared. The current is I = C*dv/dt, because dv/dt is a function of the PHY, current is proportional to the capacitive load. Cutting the load to 1/2 decreases the current by 1/2 and the power to 1/4 of the original value. For more details on crystal selection, see the Selection and Specification of Crystals for Texas Instruments USB 2.0 Devices.