[Bill Thomas] "I have an older Mac and was curious if it can even be upgraded to work with 4k (or even 1920, since even THAT format lags in Premiere Pro!). "
[Bill Thomas] "SInce I'm still testing, I have been using the MOV format at 100mbs, 59.94. Would the AVCHD format be better to edit with? (I read a previous post about some compressions, like H264, being awful to edit with)."
[Bill Thomas] "And since I probably know what your answer will be, and if I have to go to a new system, what would be the least expensive Mac I could get that would easily edit 1920 (and occasionally 4k) using Premier Pro CC?"
[Bill Thomas] "Lastly, I've been very pleased with external USB 3, 3.5" drives instead of my old SATA RAID setup. Never any hiccups, BUT it's been for 1280x720 P2 footage. "
[Bill Thomas] "EDIT: Since I prefer Premiere Pro, can you offer an argument why a PC system could be better/cheaper than a Mac? (I have had Macs forever, but I'm not married to it)."