PS4 early specs 'more powerful' than Xbox 720, claims source

[zarx]

darkknightkryta said:

zarx said:

jasongw said:

They could get away with using a Cell revision with more cores and SPU's, I'd think. When Cell launched, it was a problem because nobody knew anything about the architecture and Sony was ridiculously slow at providing proper documentation in English. If a Cell with more cores operates in mostly the same way as the existing cell, then it's a fairly straightforward matter to develop for. GPU, I think, is the biggest problem. PS3's GPU is among the last of a previous generation of GPU's that operate very differently from the current generation. It may present some problems with backward compatibility for PS4. Hard to say for sure, though.

As for RAM, they could probably do fine with DDR5, and because it's cheaper than XDR, much less XDR2, they could also afford to put more of it in. I realize many claimed that RAM speed would make up for lack of quantity, but, as a number of games have shown us on PS3, where they're inferior to their 360 counterparts, that simply isn't true.

 

I wouldm'y have thought that a modern unified programmable pipeline GPU would have much trouble emulating an older GPU, a unified shader should in theory be able to do anything a vertex or pixel shader can. The GPU in the PS3 is basically off the shelf as far as I know so no fancy "smart" EDRAM or anything exotic in the architecture like the 360 does. Not like the PS2's custom GPU and CPU architecture. Tho it's not directly compairableas the GPU would be programed "direct to metal" in the PS3, but all DX10/11 GPUs maintain DX9 compatability even tho unified shaders were a DX10 feature. I guess they could be doing that at the driver/API level, but then couldn't Sony just implement an API for backwards compatability mode that does the same? Anyway I am just thinking out loud. 

I hope you stick arround, it would be good to have someone who actually knows about this stuff arround. 

Direct X 9 series of cards can't use stuff from Direct X 10/11.  Shader programs written in Direct X 10 fully won't work in 9 (Unless you wrote them in 9 in the first place like Crysis).  And you're right, the unified shader architecture vs dedicated pipeline was the real problem with the PS3.  Hell the PS3 at launch was actually closer to a PC than the 360 was, but between the pipeline issue, OS footprint, dedicated ram vs unified, those were the real issues.  A good example of unified shaders vs dedicated would be Tomb Raider Legends.  The "next gen" features in the game would bring the game to a crawl no matter what video card was used.  Even the Geforce 9 series of cards had problems.  And why?  Cause Crystal Dynamics just threw the 360 game on a DVD and hope it worked, which is what was happening with early PS3 games.

I was talking about a presumably DX11 compliant unified shader GPU emulating an older DX9 compliant GPU, nothing to do with running DX11 code on a DX9 card or getting a DX9 engine to use DX10/11 effects. Ether of those things is obviously not possible (without rewriting the game), we were talking about maintainging backwards compatability and whether moving to a newer GPU architecture would cause problems for the PS4. I can't say I know much about the subject, but I know that DX9 engines can run on DX10 or higher cards without a problem so assumably MS managed to maintain backwards compatability when moving to DX10 and later DX11 architectures. Not that that means that Sony will be abale to do the same thing exactly as console games are often written to take advantage of quirks of the hardware meaning they will do strange and complex things that the hardware was not perhaps invisioned doing which could cause problems with compatability beyond keeping an API compatible that is why a straight hardware level legacy mode is preferable. But that is not really feasible as no one makes GPU architectures like the RSX anymore, without resorting to keeping an RSX arround for backwards compatability like the first PS3s did anyway, so a higher level solution will need to be found.