Mac Pro :: Quad Nehalem Max RAM - 16Gb - Fact Or Error?

I just found THIS

http://www.maxupgrades.com/istore/in...ategory_id=343

where they state that the max RAM is 16GB. Do they KNOW something? This would throw up in the air all my thinking about which MacPro to buy.

I am an old Mac hand (and before, Apple IIe, IIc, then Mac 128, 512, Plus, Se, IIx.... to a Dual G5 1.8GHz now), but a total newbie as far as Intel is concerned, so please pardon me if my conjectures are completely off whack, and for the large number of questions.

Looking at the ill assorted (in my view, particularly pricewise) lineup of the latest Pros, I have come up with the following ideas:

- Buy a quad 2.66 with up to 8Gb and be happy for the time being (I have 2.5GB now), with better single thread performance than the 2.26 and still 8 thread performance available WHEN there will be apps to use it (none/few of those I use do, as far as I read around, in any case, and even those seem to stop at 2/4 cores anyway).

- IF the 4GB sticks work (I know this is a big if, but given what I just found, there might be hope....), buy them at a later stage when they come down to an acceptable price and get to 16. I see a lot being written around along the lines �Even if they work, they cost more than the computer today.... etc, but RAM prices normally go down fast, so is this really an issue (except if you need 16GB NOW, of course)? And arent 8GB sticks likely to appear later on to get it to 32 if needed?

-Buy a used 2.93 or faster chip in 2-3 years. I have no idea of how cost effective this has historically been. Do prices go down significantly, or am I likely to get in the ballpark of the delta with a used, faster machine, as it often happened in the past with CPU upgrades?

-Are future chips likely to be compatible with the current machine (can someone who understand the Intel roadmap shed some light here?), or would I be limited to the 2.93 which is known to work?

-In case the 4Gb are proven to be unusable and I go for the octo, can changing chips work by replacing the 2.26 at a later stage? Knowing that I would need to buy 2, would the economics still work? It seems more unlikely, or is it?

-I remember reading about using the graphic card chip to reinforce computing power. Is this fact or forecast? Is this true of both Nvidia and ATI or (as I seem to remember) only Nvidia? If so, is it better for the long term to choose the cheaper standard Nvidia or the ATI, which seems better right now?

-Does any of these cards give an advantage over the other NOW in Photoshop, iMovie, Aperture (I have tried it on my G5, but scrolling a large collection of photos is a pain)? I do some video but no #D, nor do I think I will do in the future.

-Last quesstion for those who have a 2009 Pro in their hands, I have had always problems with USB peripherals on my G5. At some point the bus slows down to a crawl, with transfers of 1Mb/s. According to a local vendor the 2008 Pro was similar because he said it was a limitation of USB architecture, is this true? Has there been any improvement with thee better memory architecture of the 2009 Pros?