| MikeB said: @ Deneidez Multi-plats show usually which one is better. If PS3 is so great , how come its not even at par with X360 graphics in multi-plats? The more impressive multi-platform games are about on par. The reason why sometimes the PS3 version is worse is due to being different in various ways and companies resorting to cheap quick & dirty ports. Let me give you an example, the PS3 has 6 very fast SPEs for games to take advantage of (in addition to the PPE and OS workload is offloaded onto a 7th SPE). They are different compared to the PPE or Xenon core, even more legacy bagage and non-crucial features are left out but have extremely fast local memory. One of the things left out is a branch predictor, a branch predictor can enhance performance for branchy software. But the far more efficient method by eliminating branches as much as possible and manually implement branch hints to avoid mispredictions, this approach is required for the SPEs to get the best results out of them, such code will also perform better on the triple core Xenon, but the benefits will be smaller in comparison. The 8 processor PS3 Cell is much more powerful than the triple core Xenon, it's CPU is basically made out of 3 PPE-like cores, but there's many legacy code which aren't hand optimized like this, so for such code you have things up and running well on all 3 Xenon cores in a shorter amount of time and with less effort. On the PS3 you only have things up and running this easily on its PPE. What developers are now doing is rewriting their software as parallel and asynchronous as possible while moving more and more components over to the SPEs in a proper manner. It's an effort and time consuming process, but every bit of work done for one game is a step you won't have to take for your next game. That's why I stated years ago before the PS3 launched it will take quite some time before developers get the most out of the PS3's architecture, while of course still acknowledging the Cell's immense potential. |
I don't get it ...
What were the main points of those who created the Cell ?
- Rise the frequency
- Rise the number of cores
- Build a monster in floating point calculation (by putting lots of vector units online).
This was done at a time where the desktop CPUs counterparts were stuck with 2 core and limited growth possible in frequency (at that time, 2002-2003)
These objectives were attained by, between other things, reducing the logic inside the CPU of "non-essential features" like you said. As an example, a SPU has only something like 20M transistors.
As a consequence, the instruction featureset of both the PPE and the SPU have been vastly reduced.
The problem is the complexity of managing the execution of the code have been pushed back to the software.
I have read on B3D that a modern blockbuster is something like 1M lines of code.
I don't understand how redefining the way the developpers work (which they have to) can be classified as "trivial" in your mind.
Another thing on what i would like informations too is how this CPU will change what we'll have on screen in a few time. Development on the PS3 has started since 3 years or so. We haven't seen anything that cannot be done on a conventionnal CPU. We haven't seen anything that suggest a direction, "a proof" if i may say.
So, why so much faith in its capabilities ?
