PS4 XBO Difference
Texture reads(gt/s)...........56........41.....36.59%
Vertex throughput(bn). .....1.6........1.7....-5.88%
Output(gp/s)..................25.6.......13.6....88.24%
Ops/cycle......................1152......768....50.00%
TF................................1.84......1.308...40.67%
So what does it all mean?
The Texture reads are the number of textures you can "fetch" in per second from a given source. Its exactly what it means. The PS4 can grab 36% more textures per second.
Vertex throughput - Conversely, because both are tied to there clock speed, the end result is, the XBO has an advantage on just how many things it can display on screen per second (note: I'm not saying how pretty those things are).
Output- This one is a little squishy, while the raw numbers would favor Sony, the real trick here is to try and output only what is required. The more useless information you can "kill" and not output at all, the better.
Couple together the ability to store data in a compressed format, a rather large ROP cache that allows for depth testing pre pixel shader work, and you make significant gains in output. It's really really hard to come up with any sort of meaningful conclusion on this one other than to say they both have more than enough grunt to do 1080p 60fps with well over 10 overdraw easily.
Op/s per cycle.......Now here's the one that you need to get you head around and where the famous "50%" more power tends to get bandied about. A few things you have to understand about a graphics pipeline, and that is that its entirely programmable. The length and complexity of those calculations is entirely up to the programmer running for both vertex and pixel (and others these days).
I wont get to much into but lets put it this way. If dev choose a rather lengthy complex calculation to run on a pixel shader, then this will favor the PS4. If not, then it wont affect either, except for the fact that the XBO is pushing more cycles per second.
The best way to thing of it is like lines of code, this is by no means a correct analogy, but its the best I can come up with....
If the programmer runs code on shader that's less than 768 "instructions", then it favor the XBO due to its higher clock rate.
If the code is larger than 768 "instructions" then it favors the PS4.
Here's the kicker though, because this code is running "per vertex" or "per texal" ie. per model or mesh, then your still tied to your vertex throughput or texture fetch rate.
One of these does allow for the PS4's greater lines of code, by allowing for more texture fetches, but on a vertex by vertex rate? Your still limited to clock speed.
The only conclusion I make from this is, that for most tasks, shadow mapping etc it's pretty much a wash outside of clock rate.
The PS4 allows for more complex code in terms of allowing more textures per model or mesh, and more complex and lengthier code "per model".
The end result will likely be a wash in terms of most assets used. Models, the number of models, "things going on" is identical. The actual texture resolution though, this favors the PS4, whether that be through the number of textures applied to a model, or simply higher res textures.
I cant help but think of the PS4 render pipeline architecture as a snake, whose eaten a rather large meal. He has this rather large belly in the middle of it. While its head and tail are sleek.
The issue being of course, if you use that overhead "space" or not.
Conclusion:Things aren't going to be "faster" you not going to see "more things" on the PS4 graphics. What you may see is higher res textures, or better texture effects possible on the PS4. While I expect the frame rate to be steady and the same on both. My gut feeling is, that extra "bump" in the snake is there for compute calculations.
Now, what Ive left out of all of this, is the extra work that either the CPU or GPU have to do on the PS4. There is no real way of conclusively discussing that as Sony hasn't been terribly forthcoming on and additional hardware specs.
But, as things stand, there's and awe-full lot the PS4 has to deal with outside of simply drawing a polygon, that will need either CPU or GPU resources, and could impact on that extra compute claculations overhead the PS4 has.
