It depends how games will evolve over next years. But as both will have very strong 3rd party support they will deliver games for the lowest common multiple meaning 8 gb ram because no one will spend the extra effort to use more ram. Also ram is only one part of a system.

Shows how much you can follow an argument.
My assumption didn't start with "ms is scared",
My argumnet started with the op assertion
"They are not afraid and not revealing, therefore"
Hardware being the issue cannot be true
Because hardware being the. Issue would contradict "not afraid".

That's how logic works.

And if hardware was indeed very similar, they would be worried because sony said they would just improve their own specs.
Ms isn't concerned about hardware, they are going for a less powerful, features based console.

We already have evidence for this. Kinect will add to the cost. Therefore they cannot have a similarly priced system with as much power. Kinect will draw extra resources, therefore power will already be diverted.

Not so hard to figure out when you think about it, which is why I thought you didn't think about it.

I believe they are not afraid of what they saw.

Here is why (this is my point of view, these are not FACTS :)):

We already know that the CPU is going to be equivalent if not superior. And regarding what seem to be a "big deal" for certain about this DDR5; I do not see why Microsoft could not go for DDR5 too at the last minute like Sony did. Or if people believe that Sony kept this fact secret from everyone, Microsoft can also do the same.

At the end; from my point of view, Sony did not reveal anything exciting about the PS4 other than updated specs from PS3; I see Microsoft coming out with more than that. And when they saw Sony's conference it could be perfectly reasonable to believe that they are not afraid at all knowing that they already get something better (in their minds at least).

Why it is too late for Microsoft? Sony did it at the last minute...

And even if you are one of those who believe Sony kept it secret; then Microsoft could do the same.

The ps4 motherboard was built for gddr5. They just upgraded the ram sticks to be larger size.

720 would have to have been built with gddr5 otherwise, they cannot simply switch to it. It's completely different memory and a cmopletely different architecture, requiring a brand new motherboard design and GPU design. It's too big of a switch. Even if they upgrade their 8gb ddr3 to 16gb ddr3, it still wouldn't have the power of 8gb gddr5 supporting an APU.

Just to clue you in on the facts of life, the largest size gddr5 chip is 512Mb.

Sony is using 16 Ram chips to get to 8Gb.

If Microsoft is using a motherboard that accustoms regular ram 2x4GB or 4x2GB, then they have insufficient slots available to upgrade to gddr5. They would only be able to fit 2GB.

Like I said, they would have to completely redesign the motherboard to accomodate more slots.

Sony simply had 16 slots of 256MB GDDR5, and upgraded to 512MB GDDR5.

That's the difference.

No need to explain me the archicture of Sony's MB... The thing is that you have "no clue" about Microsoft's MB and this is exactly what I'm trying to say. It is definitely my personnal oppinion but rumors are rumors... And early dev kits != final console. And this is EXACTLY what I'm saying; that Microsoft may come out with gDDR5 as a surprise (with the right MB architecture) and nothing is set in stone.

You have the right to believe in rumors... I just don't believe in them; this is why I stay at high level and I'm not trying to already explain what Microsoft can or cannot do with their console as we have no idea what will be the final specs. 

By the way; thank you for explaining in details these things; they are relevant in general for people who believe in all rumors arround Microsoft's next console. Just do not be arrogant (bold quote) with me because I do not buy them (the rumors... not your explaination).

A lot of people who argue with me throw out empty statements, so I'll forgive you for the bolded. The truth is, MS already laid down their architecture by saying 8GB ddr3.

MS doesn't require gddr5 because they've tackled the issue in a different way, by using a special EDRAM. Maybe you haven't read about it?

And no, sorry, but it is too late in the game to change motherboards. System design is a very lengthy, expensive process. Shit, I even believe that manufacturing of their processors has already started as of LAST YEAR. Do you see how much time is required? No? Then that's why you believe they could make this upgrade. It's not happening Imagine, and I will bet you a month long ban that it won't.

*sigh* No. There is nothing like "slots" on the board... The chips are soldered at the "motherboard". It is far away from a standard motherboard like you perhaps know in PCs. The talking of slots is just wrong.