Compatible HD for Early Mac Pro 2008

You can put any make and any size 3.5" drive in all the bays in any combination. Also SATA 3's will work but of course at not their full maximum speed as you mentioned so SATA 2's are OK.

As an example, if you got 4 3TB's you could stuff them in there for a max of 12TB. Bit of overkill unless you really need all that space!😉

Personally I like Western Digital 1TB and 2TB blacks.

You might also want to consider using an SSD as your boot drive.

Update: I took a look at that site you linked. That 4TB limit is the max any one drive bay can support, not the total capacity across all 4 bays.

Any site saying there is a limit should do the right thing: take that down, edit, and stop saying there is some limit. Apple does that, and it just confuses people.

3TB x 4 for 12TB, only because that is the largest drive available, until 4TB drives come out.

I would recommend you go with the latest model versions and avoid the older models.

Second, probably avoid any drive that is 'green' and does not operate at 7200 rpm (5400 rpm or variable type)

Plan on using no more than about 60% gives you some room and more likely to have files located in the faster outer portion where the drive performance is best.

It is only when you get into SSDs that you can talk of overkill but even there something to look at for your system. And with 2TB WD Black and 120GB SSD both going for about $200.

They are compatible, have larger cache.

What's to know?

old = 105MB/sec new = 120MB/sec depending on drive density etc

stop worrying. they are built for wide range and HAVE to be backward compatible, not everyone buys new computer or updates motherboard every 2-3 yrs.

"a chain is as strong as its weakest link"

Although those drives could transfer data at 6GB/sec, since it never comes off the platters faster than 120MB sec, the 6GB in this case is specsmanship.

Yup. And everyone thinks SATA III is ONLY the 6G and not the improvements in the features and support for Native Command Queue, better use of dual DSP, optimized firmware, fixes for things that they found in earlier models.

SATA III (v. 3.1) will incorporate optimized features for SSDs.

More GB and TB being put closer together packed into a platter.