So, sadly, after 7 faithful years as my primary workhorse, the best, most reliable Mac I have ever owned, my Mac Pro 4,1 has died. Looks to be a CPU failure, or maybe the motherboard gave out. I was hoping it would last long enough that I could get a second gen nMP and then figure out solutions to its lack of Rosetta then, but WWDC was a massive disappointment and now I'm kind of screwed. There's no way I'm paying good money to get a first gen nMP when the hardware was already old 900+ days ago, and the sad fact is I still pretty much need a 10.6.8 box for a few things. So I think I'm getting a refurbished cMP. The question is, which one? I don't want to pick up a later one that can't boot from my 10.6.8 disk and run certain Rosetta'd apps. The obvious thing would be to get another 4,1 but I do worry a refurbished 4,1 might not last too much longer either, and I wouldn't mind a spec bump from a later cMP for only a little bit more money. It appears that I should aim for a 5,1 but I want to be absolutely certain there's no possibility of messing this up. Can somebody confirm for me there wasn't ever any firmware patches or anything that might force 10.7+ on some models? Also, which model would be best? I need a lot of RAM. 32+ GB is a must, and the option to upgrade to 64 GB would certainly be nice. I assume that won't be a problem. Also, where was the "sweet spot" on CPUs back in the day? What CPU configuration would provide the best bang for the buck? Last, but not least, what sort of GPUs are available under 10.6.8 for 5,1s?