If you're bottlenecked by your CPU, it doesn't matter what the GPU can do especially if your rendering/lighting engine is CPU-bound. I'm calling bullshit on your calling bullshit. In order for Unity to be updated such that the GPU can be used to improve AC:U on the PS4 would likely require that the entire game's engine be re-written not only off of nVidia tech optimization but also specifically to utilize PS4 hardware, making the game have two seperate development chains... which was what developers were trying to get away from in this age of skyrocketting prices. (There's also doubt on whether or not the CPU-bound bottlenecks can even be circumvented by GPGPU as we have a lacking amount of details on the whole matter (GPGPU is not some sort of magic wand to suddenly offload CPU workloads) aside from an insider developer stating that getting this game even working as it is on these consoles with high fidelity graphics has been nothing short of a clusterfuck nightmare.) Moreover, if you unload an inefficient process for GPGPU from the CPU, you're robbing the game of the ability to spend its GPU power on other aspects of IQ; this is afterall a zero-sum game of power we're working with. For all we know, when Unity launches, the PS4 version may boast better texture details and other graphical qualities due to its higher GPU specs which would have had to have been sacrificed in the scenario where you unload a potentially ruinously ineffecient process from the CPU to GPGPU just so that you can reach 1080p.

I don't disagree with the rest of the statements as they are common sense facts, the PS4 has a stronger GPU and can do more things with said GPU and Ace (and lack thereof of esdram). Ya, Ubisoft is full of shit but they're not just crippling the game out of some twisted sense of satisfaction. There are deadlines, costs, and what not else that you and I are not privy to with our armchair development discussions.

The GPGPU during idle time is basically a free boost. It's like a car turbocharger which uses the exhaust gases to increase power.

Does anyone know the X1s capabilities in this area? I know the PS4s 64 compute threads (X1 has 2) really help in this idle time, as you have the full 1.84 Teraflops to use in this idle time.

My expectation: Microsoft didn't really add to the features that you get out of the box with gpgpu, mainly because of their work in other parts of the apu and their cloud focus. They can add more support in an sdk, but I don't think they can add more compute threads with a software change.

In your op you very clearly brought into the equation a parity clause that doesn't exist. Calling bs to developers info etc. To fit an agenda.its clear after your comments what you intend with these tech talk posts. So ill let you guys carry on. I'll leave you to it.

XB1 vs PS4 is not a derail. Making this thread about "agendas" and referenda on user habits or intentions, is definitely a derail. Personal jabs stop NOW or bans will follow.

What you're describing is a case where the game is trying to reduce input latency, but that's not usually how things are done except for example for VR games (oculus, morpheus, etc...).

Usually games use pipelining so the GPU processes frame N while the CPU processes frame N+1, thus giving full 33ms to both CPU & GPU.

The XB1 is also capable of GPU compute. Thought in th e traditional sense of it. The PS4 can do 64 simultaneous GPGPU instructions while the XB1 does 4. This is just due to th efact that more of the PS4s GPU can be used for it. In addition to this the PS4's GPU has HUMA. Which basiacally means that the GPU can read and write directly to system memory and completely bypass the systems L caches. Basically, this is saying that GPGPU compute on the PS4 is an independent task that doesn't take up any CPU cycles.

And yes, MS and sony appraoched their APUs very differently. Its actually funny, sony didnt really add anything to their APU... they just tried to develop what was already on theer as much as possible while MS added ESRAM and data move engines to theirs. The XB1s APU is actually the more expensive of the two.

However, Ubisoft has way more people working for them and already released two huge games: Assassin's Creed IV: Black Flag and Watch Dogs. You don't have any evidence that Sucker Punch had "far more time" with the PS4 than the Unity team.

At the end of this day, this thread is talking about the PS4's tech, specifically on its ability to do GPGPU compute. The major takeaway from this thread is that while the PS4 and X1 APUs seem identical, they're actually very different from each other. As Intrinsic mentioned already, the PS4 can do signficantly more GPGPU instructions and has HUMA, something the X1 doesn't have. The PS4's GPU can bypass the L caches and directly access the GDDR5. The X1's APU, on the other hand, doesn't have HUMA and its CPU cannot directly access the esRAM. In constrast, the garlic and onion buses in the PS4 allows the GPU and CPU, respectively, directly access its memory pool. The point of the OP was to teach the ins and outs of the PS4 (and X1). Nothing more. Nothing less.

Ok, forget about GPGPU for a moment. As far as ubisoft is concerned and according to them they are only using its for tech that deals with cloth (soft body) physics. They said this themselves, but this is not about ubisoft using GPU compute or not.

I have tried to explain how a render pipeline works. I would have gone ito the whole deferred and forward rendering but thats big enough to be a thread on its own. So let me put it simply.

• You need to have the CPU + GPU complete their respective tasks in time for the next frame to go to the screen. You have a time allotment of 33ms.
• The CPU starts first (frame 1) and does all its processing so it can feed the GPU with what the GPU needs to render the frame. Lets say it takes a hypothetical 20ms to finish its task.
• Once finished, it hands over the instructions to the GPU. The CPUs work is done at this point and it immediately starts working on frame 2. 
• The GPU still needs to render frame 1 and output it to the screen. It however now has exactly 13ms to do this so the entire first frame ends up taking 33ms; total 20ms CPU + 13ms GPU.
• No matter how bound a game is to the CPU, at the point that the GPU is rendering frame 1 with the 13ms it has to do that its ALL on the GPU. Cause at this point the CPU is busy calculating frame 2. 
• So basically, at this point both the XB1 and PS4's GPUs have got exactly 13ms to spit out a frame. 

I understand the details, you don't need to list them out to me.

As for the quoted: yes, this was my point. They built the game on the lowest common denominator. But, as I said listen to the bombcast, there is some ambiguity if, in fact, even the PS4 is capable of more than what Unity can produce. The bombcast went into this, into the insider dev info and into a test-against-experts. There is a real issue here that, simply put, optimizing for GPGPU may not have been able to fix or would have cost too much to offload onto the GPU for some or other inefficient process.

Like I said, zero-sum game but we, as armchair developers, do not know what the sum involves.

Without being on the development team well never really know what could have been in terms of everything with unity. The ps4 Is a bit stronger than the xb1 for sure in terms of what the op has written as well as other things, but in terms of unity who knows if that was enough to make a meaningful difference.