Sony PSP from a 3D Technology perspective...

[OICAspork]

I made a threat on this before, but was too tired and I guess it was deleted as I worded it in such a way that it was more pertinent to the console forum than to 3D Technology.

These are the released specs for the PSP (I know not all of them are related to 3d rendering, but I thought it would be best seen as a whole):

Cutting Edge Technologies - aiming to explore the future...

* 90nm Semiconductor Process
* Dual MIPS R4000 core
* Vector Floating Engines
* Reconfigurable DSP Engine (VME)
* Advanced 3d Graphics Engine
* AVC (MPEG4) Decoder
* AES Crypto System
* 1.8GB UMD

21st Century Portable System - integrate all forms of digital entertainment

* 3d-CG Game
* 7.1ch Audio, 3d Sound
* ATRAC3 plus, AAC and MP3 for Music
* AVC/ @ MP for Picture / Movie
* 16:9 Widescreen TFT LCD
* Embedded Wireless LAN (802.11)
* Li-ion Battery
* Extension for GPS, Digital Tuner

Optical Disc System - seeking avantages of "Media"

* Large Capacity (3x to CD-ROM)
* Media for Game/Music/Movie/Publishing
* Lower Manufacturing Cost
* Minimize Inventory Risk
* Repoat Ordering System
* Parental LOCK System
* Regional Code System
* Copy Protection

UMD: Universal Media Disc - ultimate portable disc for SD system

* 60mm phi
* Laser Diode:660nm
* Dual Layer: 1.8GB
* Transfer Rate:11mbps
* Shock Proof
* Secure ROM by AES
* Unique Disc ID

PSP CPU CORE

* MIPS R4000 32bit Core
* 128bit Bus
* 1 - 333mHz @ 1.2v
* Main Memory: 8MB (ecDram)
* Bus Bandwidth: 2.6gB/sec
* I-Cache and D-Cache
* FPU and VFPU (Vector Unit): @ 2.6gFlops
* 3d-CG Extended Instructions

PSP Media Engine

* MIPS R4000 32bit Core
* 128bit Bus
* 1 - 333mHz @ 1.2v
* Sub Memoryc:2mb (ecDram) @ 2.6gB/sec
* I-Cache and D-Cache
* 90nm CMOS

PSP Graphics Core 1

* 3d Curved Surface + 3d Polygon
* Compressed Texture
* Hardware Clipping, Morphing and Bone (8)
* Hardware Tessellator
* Bezier and B-Spline (NURBS)
* EX 4×4, 16×16 and 64×64 sub-division

PSP Graphics Core 2

* 'Rendaring Engine' + 'Surface Engine'
* 256bit Bus, 1-166 MHz @ 1.2v
* VRAM: 2MB (ecDram)
* Bus Bandwidth: 5.3gB/sec
* Pixel Fill Rate: 664 M pixels/sec
* MAX 33 M polygon /sec (T & L)
* 24bit FULL Colorc:rgba

PSP Sound Core: VME

* Reconfigurable DSPs
* 128bit Bus
* 166mHz @ 1.2v
* 5 Giga Operations /sec
* CODEC
* 3d Sound, Multi-Channel
* Synthesizer and Effecter

AVC Decoder

* AVC (H.264) Decoder
* Main Profile
* Baseline Profile
* @ Level1, Level2 and Level3
* 2hours (High Quality) - DVD Mobie
* 4hours (Standard Quality) - CS Digital

I/O

* USB 2.0
* Memory Stick
* Extension Port (reserved)
* Stereo Head phone Out

Communication

* Wireless LAN (802.11)
* IrcDa
* USB 2.0

I was particularly wondering how these specs compare to the Bitboys Acceleon series and the powerVR MBX. Also, as this is stated for launch around Christmas of next year in Japan... how do you think it will stack up to mobile solutions of that time. Looking at those specs... it seems like it will be quite a challenge for Sony to keep heat and battery drain down to respectable levels.

Hmm... I just stumbled across this post by Buggy Loop at rage3d suggesting that Nintendo could answer this with a portable gamecube... and compares the specs of the PSP to the GC here:

http://www.rage3d.com/board/showthread.php?s=86e7527f92541fe43d7cb5fd3827e72f&threadid=33701548

Any thoughts!?

 

[Dave H]

In general: my first thought upon seeing these stats posted a couple days ago was that they had to be a hoax, because there were just too many chips there. Two CPUs, two GPUs and a sound chip? Five ICs in a handheld, for god's sake??

Of course five cores doesn't have to mean five chips. And in this case, they're apparently cramming five cores into one IC! And 12MB of eDRAM to boot!! This is one hell of an SoC.

Also probably a reasonably intelligent way to do this sort of thing. Especially given it's Sony--enough expertise to put some MIPS cores together and fab the thing, but not enough to design an MPU from scratch. I wouldn't have thought a mini-PS2 was necessarily the approach to take, but now that I see it it does make a reasonable amount of sense.

Re: graphics: that list of stats misses one of the most important numbers from a 3d point of view--the screen resolution. It turns out to be 480x272. That's quite reasonable for a high-end handheld, of course, nothing too surprising...

Until you take a look at the GPU on this thing. It's listed with 664 MPixels/sec @ 166 MHz--in other words, a straight-ahead 4 pipeline design, clearly a 4x1. Even so, 4x1 seems a bit brawny for the handheld market, which usually gets 1x1 or maybe 2x1 designs thrown at it.

Here's why: fillrate obviously only makes sense in conjunction with resolution. The relevent issue isn't fillrate alone, but rather fillrate per pixel of resolution.

And by that measure PSP is a an absolute monster. If you compare it to a PC at very moderate resolution, PSP has the same ration of fillrate to resolution as a GPU capable of 4 GPixels/sec rendering at 1024x768. Now, we thought we had that in the 5800Ultra, but it turned out to be only 4 GTexels/sec. As it is, the closest we've come is the 9800 Pro, at 3040 MPixels/sec. And that fillrate power isn't really intended for fixed-function fragment rendering @ 1024x768. W.R.T. fixed-function stuff, it's for trilinear and AF and hugely high fps @ 1600x1200. Or it's for bringing to bear on pixel shaders.

But the PSP doesn't appear to have programmable pixel shading (although one would presume the geometry program functionality that can come out of the "media engine" and the "graphics core 1" should be pretty impressive). High fps of the sort seen on a PC with a high-end GPU would be wasted on a tiny LCD screen. And, at a resolution like 1600x1200, PSP's fillrate-to-resolution ratio suddenly compares to a 9.8 GPixel/sec GPU!

So what gives?

One obvious option is supersampling. The issue here is the size of the framebuffer. 2MB of video RAM doesn't give one much to work with. 2x2 SSAA, assuming 24-bit color back and front buffer, and 24-bit z buffer, works out to...3.4MB. That's obviously not going to work. 2x1 SSAA works out to 1.9MB, which doesn't exactly leave room for textures.

Of course...the PSP doesn't have to have a z buffer. And indeed, the fact that it's not mentioned would lead me to believe it doesn't. (Does PS2?) Even so, we're still left awfully low on framebuffer space to use SS much of the time.

So what is all that fillrate there for? The last thing to mention is how the PS2 is similarly overburdened with fillrate--it has 16 pixel pipelines for 2400 MPixels/sec fillrate, similarly absurd (if not more so) given the TV resolution it renders at. The best I'd seen anyone make of that situation is that they are frequently empty. But then what's with the same design (PS2's 4MB video RAM is similarly tiny given the ratio of TV to PSP resolution) doing on a new product?

It occurs to me I'm missing something here. Does PS2 even use that 4MB for the framebuffer? (Where else would it put it??)

Hmm.

Anyways, I know enough to know it's extremely similar to the PS2. But I don't know enough to know why that could be a good idea... :?

 

[akira888]

The PS2 does indeed have a Z-Buffer. And I don't think that we can say definitely at this point that PSP doesn't have some sort of register combiners for its blend modes; not that many details were given about the functionality of the chips themselves. It's also possible that Sony is using some form of anti-aliasing that doesn't require multiple frame buffers, perhaps something along the lines of Matrox's FAA. And textures could probably be stored in main memory due to the fact that Sony finally decided that texture compression was a good idea after all.

 

[Dave H]

The PS2 does indeed have a Z-Buffer.

Ok, thanks. Am I right in thinking it uses the 4MB local VRAM primarily for framebuffer, then?

And I don't think that we can say definitely at this point that PSP doesn't have some sort of register combiners for its blend modes; not that many details were given about the functionality of the chips themselves.

I suppose not, but enough bullet points were listed that I would think "programmable pixel shaders" would have been one of them. Although perhaps that's what's meant by the inane Sony-term "surface engine".

It's also possible that Sony is using some form of anti-aliasing that doesn't require multiple frame buffers, perhaps something along the lines of Matrox's FAA.

Quite true. I actually meant to mention that but forgot,

And textures could probably be stored in main memory due to the fact that Sony finally decided that texture compression was a good idea after all.

True, in particular as the decompression seems to occur on graphics core 1, as the results would be used by graphics core 2. Perhaps textures are stored compressed in "main memory" (which is just the 8MB of eDRAM near the CPU), then decompressed by GC1 on route to a place in cache of GC2.

 

[PC-Engine]

There won't be 8MB available for compressed textures. What about the game code etc.

 

[bdmosky]

Anybody else thing that perhaps Sony is just being a little overambitious in it's designs as of late? I'd hate to see this project become as bloated as the PS3 with rising R&D costs and an ever-changing release date. I just don't see Sony fitting this all out the door on time while still producing something that is truly portable.

 

[akira888]

There won't be 8MB available for compressed textures. What about the game code etc.

I didn't mean literally that all 8MB of main memory would allocated for textures, merely that was a possible place to store them due to the fact that loading compressed textures out of main memory is a fairly bandwidth-inexpensive operation compared to noncompressed textures. PS2 for example can chew through bandwidth on texture access.

Anybody else thing that perhaps Sony is just being a little overambitious in it's designs as of late? I'd hate to see this project become as bloated as the PS3 with rising R&D costs and an ever-changing release date. I just don't see Sony fitting this all out the door on time while still producing something that is truly portable.

So far the PS3's release date hasn't changed largely due to the fact one has never been given except through sheer speculation. And I'd rather see Sony be overambitious than underambitious, which has often been a problem for them. (poor Betamax/Memory Stick licensing, no portable in 10 years, no 4 player support out of box...)

 

[Ailuros]

Anybody else thing that perhaps Sony is just being a little overambitious in it's designs as of late? I'd hate to see this project become as bloated as the PS3 with rising R&D costs and an ever-changing release date. I just don't see Sony fitting this all out the door on time while still producing something that is truly portable.

No I was thinking actually something else. SONY´s architectures so far looked impressive JUST on paper.

 

[akira888]

Am I right in thinking it uses the 4MB local VRAM primarily for framebuffer, then?

In theory that would be the best way to organize the memory system as front buffer data units are on average much more "read/write intensive" than texture data and will therefore benefit the most from being stored on a more local, faster memory. However a problem arises due to the fact that the RDRAM->EE->GS pipe has some fairly nasty bottlenecks (such as the small size of the EE's caches), and therefore its not so easy to load textures out of the 32MB buffer every frame.

 

[akira888]

No I was thinking actually something else. SONY´s architectures so far looked impressive JUST on paper.

Not neccessary true Mr. Cat as the Playstation was a fairly good rendering system for its day, and the PS2 could have been much better with only a few minor changes (loopback, bigger data/insty cache on the EE, texture decompression on the sampling units, dot3 blend mode).

Off Topic: Are you from Greece by the way?

 

[cthellis42]

Plus that STEEEEEP learning curve. (Which at this point I think was a GOOD thing to train devs on, as it looks like it will only get harder with the PS3. Hehe...)

Meanwhile, for a 20 month older machine, I think it keeps pace quite well.

 

[Dio]

One point on the fillrate: it seems likely to me that there will be a TV-out on the PSP (to play the "DVD's" if nothing else) - so is it possible that games will render at a higher resolution when connected to a TV?

 

[Josiah]

all right I'll post this here...

 

[MfA]

I dont think the PSP will be all that hard to program. Instead of a VU running independent programs ala the PS2 it seems to simply execute vector instructions from the instruction stream for the main processor, also the second MIPS core isnt meant to be used for gamecode AFAICS.

So what we are left with for the game developer is a CPU with a SIMD instruction set and a GPU consisting of a vertex and pixel shader, sounds familiar ...

 

[Ailuros]

No I was thinking actually something else. SONY´s architectures so far looked impressive JUST on paper.

Not neccessary true Mr. Cat as the Playstation was a fairly good rendering system for its day, and the PS2 could have been much better with only a few minor changes (loopback, bigger data/insty cache on the EE, texture decompression on the sampling units, dot3 blend mode).

Off Topic: Are you from Greece by the way?

Set a PS2 and a Dreamcast in realtime side by side and you´ll have your answer to the above.

As for the OT question, the answer is positive.

 

[Grall]

Anybody else thing that perhaps Sony is just being a little overambitious in it's designs as of late? I'd hate to see this project become as bloated as the PS3 with rising R&D costs and an ever-changing release date. I just don't see Sony fitting this all out the door on time while still producing something that is truly portable.

Well, considering Sony hasn't even GIVEN any release dates yet, I'm sure the rest of your FUD is entirely correct as well...

*G*

 

[Vince]

Well, considering Sony hasn't even GIVEN any release dates yet, I'm sure the rest of your FUD is entirely correct as well...

This is what happens when you believe the Inquirer.

PS. Ailuros, the DC/PS2 comparisons died out circa 2001 (around when the 2nd generation PS2 games emerged).

 

[Ailuros]

PS. Ailuros, the DC/PS2 comparisons died out circa 2001 (around when the 2nd generation PS2 games emerged).

Depends which comparisons you actually mean. I've always been quite sensitive to aliasing.

It's no secret that the DC suffered a quick death two years ago, but that doesn't change the fact above one bit.

 

[swaaye]

To be honest I'm more excited about 3D enabled PDAs.

It's sort of like the PC vs Console idea, where the PDA is more functional for other tasks than the portable game console.

After using a Sharp Zaurus (and losing it cuz I busted the screen ) I definitely miss it's amazingly flexible capabilities. I could play full PC Doom and LucasArts adventure games on it and then switch to Opera for the web or PDF viewer for documents, or handheld Word, or MP3/Ogg playing, the list just goes on and on.

And, something tells me this Sony Handheld will cost similar to many PDAs. I'd also imagine PDA tech will also have advanced some by the time this thing hits the market.

 

[Vince]

It's sort of like the PC vs Console idea, where the PDA is more functional for other tasks than the portable game console.

While I don't think you'll be word processing, the goals Sony have for PSP seem to be a bit beyond simple classical Nintendo gaming. Digital Media would be playable threw the UMD aswell as the possibility of it being part of the future Sony networking fabric for their branded media via 802.11.

Then there's also things like their recently presented first single chip GPS solution from the 2003 Symposium on VLSI Circuits that were mentioned. So, it could get somewhat interesting indeed.