Predict: The Next Generation Console Tech

Maybe, but legally and ethically defensible are two different things and many were skeptical that AMD could pull off the dual contract, so the oneous is on AMD to be above any hint of impropriety.

But hey, if Sony is totally cool with the end result then yea no problem.

 

That's the best explanation, but it's not exactly like that. Hardware needs to provide developers with resources to be used in making their games. Back around the year 2000, Sony, like others, were looking at very programmable, fast throughput, which is flexible enough to render graphics, encode and decode video, crunch through AI datasets, etc. So they set about developing a high SIMD chip. Whether MS really wanted a high SIMD chip themselves in the initial design, or just reacted to the Cell noise, we might never know.

Once those chips found their way into the consoles, the developers used them to calculate whatever functions they needed. Which more-often-than-not was graphics tasks. During that time, GPU's have developed to be more flexible with their computer power, meaning the development of high SIMD CPUs has taken a back-step once again.

It's not that workloads have changed, or designers overestimated anything. You can never have too much power! It's just that the economies of providing flexible compute power have shifted once again. Maybe there's a recognition that all that compute power gets spent on graphics anyway so it can be moved into the GPU anywhere, but I dare say that it's a simple price/performance balance this time around.

 

4 Core Haswell would be twice that - 409.6 GLFOPS via AVX2.

Current Sandy and Ivy bridge processors peak at 204.8 with 4 cores at 3.2Ghz.

 

It does not have 64 bit vector units.

 

I know that. My point is that a core with 128 bit vector units and 0.2 IPC can be easily be outperformed by a smarter core (even by 2005 standards) with 64 bit vector units. I wonder whether the Xbox 360 design team expected game code to achieve such a low IPC. The actual IPC achieved by game code this generation might be one of the reason to go with Jaguar cores, which are clearly lacking in terms of peak floating point throughput (by 2013 standards) this time around, rather than, for isntance, PowerPC A2 cores.

 

The apocryphal history states that MS actually wanted an out of order CPU for xenon, but IBM could not deliver in the required timeframe. In terms of actual workload, a jaguar core is more than a match for a xenon core, even with the dual issue. The only place you'll have problems would be highly optimized streaming vector calculations, used extensively by most audio engines. With very few jumps and a nice large data set, a xenon core would almost double the performance of a jaguar one.

 

I would be curious what kind of flop throughput is actually sustainable on the 360's CPU. my guess is that it's probably below 50% (if not a lot less) of the peak. I just can't imagine the memory and caches being capable of sustaining data for that kind of performance.

 

It's got enough registers that for the right workload, where you can actually accommodate the memory latency, you could hit close to 100%

But that's not really indicative of real workloads.

I've always maintained than both the 360 CPU and Cell were focused on the wrong things, designed by marketing.

10 years ago in order CPU's were back in vogue, many people thought that compilers could solve the scheduling problem, it didn't happen.

 

No high-performance system can provide sustained peak flop throughput. A 32 bit calculation requires 4 bytes (let's take it as 4 bytes in addition to what's in registers, rather than having to load two 32 values to operate on). 1 gigaflop would thus require 4 gigabytes per second of bandwidth. 100 GFlops would need 400 GBps, outstripping every bus available by a mile. A 1 TFlop GPU would consumer 4 terabytes of data a second sustained peak...

If your code can operate out of caches/registers, recycling the data being consumed (a set of serial operations applied to the initial data), you can get better flop throughput, but that's a limited set of code.

 

I think Xenon's often quoted 115.2 GFlop/s are really a bit optimistic.
It assumes issuing one 128Bit FMA/DotProduct (8 flops) in the VMX unit + another 4 flops from another instruction for 12 flops per cycle and core.

 

It was 77 GFLOPs, for Xenon's theoretical performance; according to this IBM graphic reference (within the Forbes link).

EDIT: "The 115.2 figure is the theoretical peak if you include non-arithmetic instructions such as permute. These are not normally included in any measure of FLOPs."

 

If the heaving lifting code on the SPEs is vertex culling, compute shader workloads for complex illumination, mesh skinning, post processing...they are tasks ideally suited for GPUs; no GPGPU about it. SPEs are AFAIK mostly used for graphics tasks that the RSX isn't great at.

 

Just as an aside, how long does it take to design a custom cpu from the ground up, and what size of an engineering team are we talking? Be it IBM, Intel, whatever.

 

But there's a lot of image decoding and processing for the Kinect-2 or Move (or even the rumored kinect-like eyetoy), there's decryption and decompression from the disk media, with an SSD it's going to need 10 times more processing, RT compression for a remote display (WiiU or PS4->Vita, 720->phone/tablet), more complex physics and particles and water become possible, isn't that all much easier on a real CPU with gobs of FP performance? I mean processing a point cloud and comparing to a database for the Kinect can't be easy to do on a GPU.

 

Image decoding and processing is probably better suited to a GPU. video encoding is more efficient with custom hardware. Decryption and decompression doesn't need gobs of vector maths. More complex physics and water - PhysX on nVidia GPUs says hello. Leaving AI, audio, and housekeeping, which a multicore general purpose processor will be fine for.

 

Some comments from Arthur Geis from NeoGAF.

http://www.neogaf.com/forum/showpost.php?p=45254953&postcount=3287

http://www.neogaf.com/forum/showpost.php?p=45255522&postcount=3296

 

ish... I'm sorry.

 

Spoiler

that thing is to kill anything "next gen" about "next gen" systems...
It's a monster

What makes me kind of sad is that whereas it never shipped when I read the 'few" here that had the chance to play with Larrabee I've the, may be wrong, sense (reading to much into), that they really enjoyed working on it.

 

I can't tell if he is talking about the next xbox or Sony Orbis

 

Well we had mostly heard about the older Orbis target specs with 2GB of GDDR5...

As for the "next-gen" game that "we're" already playing, I do recall a Skyrim interview saying as much.