It just shows that to develop for Wii U, you have to know what you're doing with the eDRAM. If you don't, then you've likely mess up the coding and will lead to under-performing parts. Similar to the CPU as well, if you don't know what's going on, then it will perform badly.

"Each game team would have to develop special technioques in order to manage it."

"It takes a while to figure out how to use it, but once you understand how to use that little cache of eDRAM, you can unlock the full potential of the hardware."

In other words, what I and many others have been saying all along, and straight from the mouth of Cerny Computer Entertainment.

Yes, he likely went on to explain the advantages of the PS4 approach and I have no doubt it's GDDR5 setup is better, but that doesn't change his statement than the eDRAM approach Wii U uses has its own strengths and is not as weak as some people like to think.

The 360 has 10MB eDRAM, the Wii U has 32MB. 

Cerny makes an example of Edram having a potential bandwidth of 1TB with a small pool of memory paired with a much larger slower pool of memory, and how simply having one pool of high bandwidth memory is the better solution because it removes hurdles which developers have to jump making their lives easier, hence their decision to with with 1 large and fast pool of memory, But you take this as Cerny stating that the WiiU has 1TB of bandwidth?.....wow....just wow.

For reference, the 360 has 10MB of Edram, it only has a bandwidth of 32GB/s from the GPU to the Edram, but internally the Edram has a bandwidth of 256GB/s to the ROPS.

Currently there is no definitive information about the bandwidth of the Edram in the WiiU, there are only educated guesses people can make, but if we take the whole WiiU design into consideration, one can easily see that although the WiiU has an efficient and somewhat customized architecture, the parts themselves aren't aren't top end, from an old GPU architecture, an even older CPU architecture, to the very slow DDR3 ram used.

From this, one can make the assumption that the Edram bandwidth will not be on the top end of the scale rather it may be on the lower end of the scale, perhaps even lower than what is found on the 360, I say this because Edram is very expensive at high capacity and high speeds and the WiiU has 32MB of it, compromises would have to be made to balance the system and speed would most likely be the first thing cut. Why put in Edram with a bandwidth of 1TB/s if the current WiiU GPU will never be able to take advantage of it?, kind of a waste. For reference the Nvidia Titan, only has a bandwidth of 288GB/s.

The fact of the matter is, the WiiU is NOT a graphics power house, it never was and never will be, that is the domain of the PS4 and Xbox One. This however does not mean that the WiiU won't be capable of nice graphics, because it will be, just look at what these 7 year old machines, PS3/360, can do, I am sure that the WiiU with a more modern GPU and more memory will be capable of some very nice games, it's just that when it comes to multiplatform games, they will look and run a hell of a lot better on the PS4 and xbox one

The point is, (technically uninformed) people ignore Wii U's eDRAM, point to its main memory and say, "oh look, it's so slow" without realizing the advantages eDRAM gives. This video nicely demonstrates how such an advantage works.

For thoses that do not know, caches (like Wii U's eDram) exist because of the Locality of Reference.

While the unified PS4 memory hierarcy is very simple and consequently easy to use, the funny thing about eDRAM is that a developer can easily write a program to sniff the RAM memory accesses while playing a game so you will be able to know what are the best assets to be promoted from the RAM to the eDRAM.

How you DARE bring facts and knowledge here?!... But anyway, I always had the idea that the Wii U's eDRAM was gonna be used for 1080p and AA, but this has not been the case...

OT: I thought we had agreed that the Wii U's problem was not it's weaker hardware, which is not THAT far from the other two, but third parties not wanting to fight against Nintendo's games for sales.

The whole point of Edram is to compensate for the low bandwidth of the main memory because graphics rendering is bandwidth intensive and low bandwidth DDR3 would cripple it. There is also the business equation to it, spend a more money on small pool of fast ram, then put in larger, slower, cheaper ram with the overall cost being cheaper than just using 1 large pool of high speed ram, the compromise there is the overhead you give developers.

In the end its two solutions for the one problem as described in the video, Cerny's approach was to reduce developer overhead as much as possible which led to him favouring 1 large pool of high speed ram. The thinking I guess is that you spend money now on ram, but reduce the difficulty and thus reduce the cost or at the very least maintain the cost of developing rather than have it exponentially grow again.

PS4's approach was probably chosen for being easier to develop for, yeah.

I'm not arguing Wii U's approach is better, I'm just saying that by explaining the value of the eDRAM approach Cerny does show the inaccuracy of claims that point to Wii U's main RAM bandwdith and judge the system on that while pretending its 32MB eDRAM doesn't exist.

That right there is developer overhead, something developers don't need to worry on the PS4.

Xbox one at least has the Move engines which in a way try to automate that process you described in hardware, again reducing developer overhead.

Moving data required for rending to Edram will become more and more a headache as developers try to squeeze more juice out of the GPU in later years...this is exactly the hurdle that Cerny thought about and why he pushed forward with the much developer friendlier architecture in the PS4.

I'm not that tech savvy, but wouldn't developer's experience dealing with the EDRAM in the Xbox360 help somewhat in developing for the Wii U? I understand that they still have different architectures, but surely the programming of code for use between the DDR3 and the EDRAM involves a similar process between the two consoles.