Reference Board Examination
There's no difference in PCB layout or heatsink design when comparing the PRO and XT. The functional differences are in the R420 GPU itself (one quad pipeline disabled) and the memory modules.
The PRO board uses 2.0ns Samsung GDDR3 DRAMs, compared to the GC16 1.6ns variant on the XT. That allows for a maximum theoretical clock at default voltage of 1000MHz. With the memory clocked at 900MHz initially, the opportunity for a large increase on the memory clock when overclocking is slightly limited.
Like the XT, the PRO reference board features the familiar connectivity options of DVI-I, S-Video (input and output using the Rage Theater processor) and 15-pin analogue VGA.
Like the XT, ATI's AIB partners are actively encouraged to equip their boards with dual DVI ports, but it remains to be seen if any will. Of the AIBs offering boards for pre-order, all are currently sticking to the reference design in that respect.
