I went ahead and got one of these: http://www.newegg.com/Product/Product.aspx?Item=N82E16814102858&cm_re=5770-_-14-102-858-_-Product And there is some good news. I dumped the ROM and had a look. (attached) It has 43K of free space in middle. Pretty sure from memory that this is MORE than the 4870 EFI portion. And with a 128K chip. There is even another 1.6K empty at the end, so we could move the GDDR5 table down a smidge to grab some more space, if we change the MCUC address, like with some 4870/90 ROMs. So, unless Apple BLOATS their EFI, there is a GOOD chance that just like 4870, we will be able to flash most if not all of the 5770 cards. By this I refer to likelihood that Mac ROM will fit on the EEPROM chip present on PC 5770s. While the GTX285 flashes beautifully ONCE YOU PUT A 256K EEPROM ON IT, which is unfortunately impossible for 99% of people. We may be able to avoid all that soldering with these. If Apple gets the EFI portion over 45K we may be in trouble, however. I was unable to get even basic functionality / frame buffer from 5770 with any version of ATY_Init I could find. I attempted to place the BIOS into the ATY_Binimage field, but even without 3000 kext, I got a KP. So, I probably didn't do it right. Netkas could do this better but it seems likely that he reason to believe that it won't work any better than 5870, as he has written 5770 ATY_Init for Hacks that specifically mentions "not for Mac Pro" I can completely understand if he would rather wait a week or two until final ROMs / drivers make it out into the wild as many current problems will likely go away, and some new ones might very well show up. Can't wait.