About EE, GS, software emulation and PS2 compatibility

[The Seventh Taylor]

When PlayStation2 was originally released it had two major chips: the Emotion Engine or EE for short – basically the CPU – and the Graphics Synthesizer or GS – basically the GPU i.e. graphics processor. Sony Computer Entertainment then went on an ambitious path of shrinking steps, making a process shrink of the EE every year for at least 3 years and even 5 shrinks of the GS in just 4 years. The next step after that was combining both processors on a single die, which was one of the advances enabling the design of the radically more compact version of PS2, let's call it PStwo.

(picture credit: Impress Watch)

When the PlayStation3 first came out, model CECHA01, this single-chip EE+GS was prominently mounted on the motherboard, as evidenced on this picture from a teardown report by Dailytech. A similar dissection appeared in Impress' PC Watch.



When the second generation of PS3 (the 80GB version) was announced, Sony declared that they left out the Emotion Engine. PS2 compatibility by hardware emulation was replaced by software emulation. Now I wonder: did they also leave out the Graphics Synthesizer? Could they emulate the EE on the Cell BE microprocessor but perhaps not the GS on the RSX graphics processor?

If so, the GS was removed in the third generation of PS3, the 40GB version. There’s no trace of it on this picture from an article where PC Watch takes apart an CECHH00 model.



(Note that Sony has not been very specific about the GS. This article mentions it but the words in brackets have been added by the author.)

This would explain why Sony does not offer PS2 compatibility in the 3rd generation: apparently the emulation wasn't entirely software-based.

Now this hypothesis may very easily be debunked by pictures of the internals of a 2nd-generation PS3. Yet while there are millions of such units in the world I have not come across any pictures of its inside. Anyone who has, please post a link here.

[Brandon B]

I recall a statement by Sony that it was exactly that, removal of the GS from the hardware and its lack of emulation in software that removed the PS2 functionality from the 40GB model.

Can't find a specific link now though.

[Jens]

This article from Beyond3D about the initial European version i.e. the second generation is very specific about it. It not only mentions the GS specifically but also discusses its place in the new architecture.

The article contains a like to this Italian site that shows a picture of the second motherboard.

There's another analysis on NeoGAF comparing the first and second board, with a funny GIF alternating the two.

Mystery solved (if there ever was one)

[D-Mode 5.1]

Correct. It's also simply explained on Wikipedia:

http://en.wikipedia.org/wiki/PlayStation_3#Retail_configurations

[The Seventh Taylor]

Not sure what they're hinting at here but it sounds to me like a suggestion about software emulation of the Graphics Synthesizer (on the RSX GPU, I presume):

http://kotaku.com/355645/is-playstation-3-backwards-compatibility-dead-maybe-not

[Jens]

There's some technical coverage regarding an alternative way to do PS2 emulation on PS3 in software here:

http://www.siliconera.com/2009/06/29/sony-patents-emotion-engine-emulation-technology-for-cell-processors/

What I'm wondering about though is whether they can get it to work in practice. It sounds like a great idea in theory and that may be enough to obtain the patent but I'll believe it when I see it working.
I'm surprised the 'analysis' doesn't say this. Instead it says "According to a recent patent filed by Sony Computer Entertainment in the US, Sony has the code and technology ready to do this." I don't think a patent says anything about technology actually being ready.

Let's see what happens next. Perhaps a major firmware upgrade v3.00 by the end of the year, to coincide with the launch of PS3 Slim?

[The Seventh Taylor]

If anyone comes across good pictures of the inside of PS3 Slim, please post (links to) them here. I'm very curious.

[PS3SACD]

Well, here they are: from a teardown of PS3 Slim by iFixit.