You're taking shortcuts by purchasing RAM slower than the recommended speed. You clearly made up your own story from the rest of my statement.
I don't recommed Apple's brand but recommend Crucial so I don't know where you got that from.
When the Mac Pro was released, no one made a 4GB module. How was Apple suppose to know it would be compatible with something that was not out in the market.
Assuming things and taking short cuts about anything more often than not will lead to undesirable outcome, am I correct? If no one can give a definative answer to your question, I would buy something you know is 100% guaranteed compatible with the new Mac Pro. That's all I'm saying.
One word of wisdom, when people don't reply to a thread, it's often because the question is too obscure for anyone to answer with 100% certainty or because it has a really simple, obvious answer.
Good luck with your quest.
At the end of your first post, you said something to the effect that "Taking shortcuts will bite you in the butt." Nowhere in your post did you say anything about crucial being good or bad, you left it to me to decide what you were trying to say. And since you didn't praise crucial and put in some remark about taking shortcuts (without explaining what the shortcuts comment meant), I deduced that you were saying crucial ram was a shortcut.
As far as my comment about the previous Pro system handling 32gb of memory, my point was that up until the end, Apple always said 16gb maximum. That wasn't true and proof that sometimes even glorious Apple doesn't know everything. They are pretty obscure themselves as far as backwards compatibility goes and this is a question that obviously, at least one other person had.
I never said I was going to spend $300 on ram that I might not know for sure would work in my system or not. I'm doing research and hence, asking questions. Since I'm sure not everyone reads the rumor's section, I figured I would try to get the attention of people in the proper section of the forum, the Desktop section. Sure I asked the question 3 times, but thats because I want a solid answer. "Doubt it" was something we used to say (when I worked for Geek Squad) if we didn't know but wanted to leave a little breathing room in case we were wrong. "Doubt" is a ridiculous word and an attempt for someone to sound smarter than they actually are without too much risk of actually being wrong (this isn't an attack on you bry, its an attack on the word). "Doubt" does nothing more than create more "doubt".
Okay, end rant. I'm not taking shortcuts (at least in my definition) and I haven't decided what ram I'm getting. I may very well order it from OWC since they are the only ones I can find that are carrying FB, ECC, PC2-6400 memory at the moment for a decent price. I'm just looking for answers to questions. And if you could find that link to the site you were talking about previously, it would be much appreciated