ATI's HD 4770 has a maximum board power consumption of 80W and that's by 5 Watts more than the PCI-Express slot can deliver.
The cards current clocks are 750MHz for the core, and 800MHz for GDDR5 memory. As you all know this RV740 card will be ATI's first 40nm desktop product that will hit retail. The clocks aren't final yet so we guess that some things might change.
AMD is still pretty much silent about the rumored HD 4750 that should have a RV740 GPU paired up with GDDR3 memory, and we guess that this one could end up without the PCI-Express power connector, but we couldn't confirm that at this point since the HD 4770 is scheduled to release in the first week of May, probably on the week of May 4th..
AMD wants this card to compete with Geforce 9800 GT and we guess that AMD is much better in this game, as it plans to sell this card for US $99.