Help me compare MBX and the GoForce 4500

[Shogmaster]

My professional training is an artist, so deciphering much of this tech stuff is beyond me, but I'm still very interested in comparing the capabilities of PowerVR MBX to the newly announced nVidia GoForce 4500.

Some links for you guys to draw from:

PowerVR MBX -
http://www.powervr.com/Products/Graphics/MBX/Index.asp
http://www.arm.com/miscPDFs/1643.pdf

nVidia GoForce 4500 -
http://www.nvidia.co.uk/page/goforce_3d_tb.html.html

What I have digested somewhat so far:

- MBX is rated higher in triangle count (1.25~2.5M for Lite to Pro, and "over 1million" for GoF4500).
- GoF4500 may have the edge in multitexturing (6 simutaneous textures vs "2 layer" textures for MBX)
- GoF4500 has higher internal color precision (40bit v 32bit)
- MBX can drive higher res LCDs (XGA for MBZ Pro v VGA for GoF4500)
- Both support programmable pixel shaders? (GoF4500 definitely, not sure about BMX)
- Both provide hardware T and L (MBX Pro offers Vertex Geometry Processor option, and GoF4500 seems to have one built in)

Can anyone help me correct or add to my info? Thanks a bunch.

 

[Luminescent]

According to the .pdf on the Nvidia site linked above, the specs for the 4500 are higher than indicated in the previous post:

3D ENGINE
• Geometry transform engine (floating point
and fixed point)
• 16-bpp (RGB565) color with 16-bit Z (high
quality dithering)
• 40-bit color pipeline with signed non-integer
color (over bright)
• 8 surfaces (color, Z, texture 1-6)
• Programmable pixel shader
• Fog, perspective correction, alpha-blending
• Mip-mapping
• Bilinear/trilinear filtered texturing
• 4/8-bit palettized texture, 16-bit
(1555ARGB, 565RGB, 4444ARGB)
• Multitexture support (up to 6 simultaneous
textures)• Super-sampled antialiasing
• Compressed texture support (DXT)
• 250 million pixels/sec.
• 5 million vertices/sec.
• 5 million triangles/sec.

No mention of "programmable" vertex shaders as with "programmable pixel shader", which leads me to believe the geometry processor is fixed function in the 4500.

It also seems the 4500 sports two "traditional" pixel pipes, being that 125 MHz is likely/plausible for a portable gpu.

 

[Shogmaster]

The only thing I see different is the "5 million triangles per second" instead of "over 1 million" of the previous page. Also, it sez 5 million vertices per second as well. That's kinda wierd, isn't it? If you can draw 5 million triangles per second, than you should be able to calculate far moe than 5 million vertices per second, no?

Yep. I'm way confused now. @_o

 

[Luminescent]

From the information given by both PowerVR and Nvidia, the following conclusions on 4500 vs. MBX HR-S (.13 micron) seem plausible:

Max Vertex Output:

4500 (5 million triangles/sec) > MBX (2.5 triangles/sec)

Max Pixel Output (Effective?) :

MBX (>480 million pixels/sec) > 4500 (250 million pixels/sec)

Pixel Processor Precision:

4500 (40-bit) > MBX (32-bit)

Texture Precision (Max):

MBX (32-bit) > 4500 (16-bit)

Z-Buffer Precision:

MBX (32-bit w/FP support) > 4500 (16-bit)

Color Output Precision (Max):

MBX (?) ? 4500 (16-bit)

Max # Texture Layers Per Pass:

4500 (6) > MBX (2)

AA Performance:

MBX (Free FSAA) > 4500 (Super Sampling=fillrate/2)

Pixel and Vertex Functionality:

4500 (FF Geometry and Programmable Pixel Shaders) =
MBX (Programmable Vertex Shaders and what seems to be a Configurable Pixel Pipeline)

Miscellanious Functionality:

MBX (per vertex fog, full range of blend modes, support, point, bilinear, trilinear and anisotropic filtering, flat and Gouraud shading, perspective texturing, specular highlights, alpha test, compressed texture support)
>
4500 (fog, perspective correction, alpha-blending, mip-mapping, bilinear/trilinear filtered texturing, compressed texture support)

Overall:

MBX

 

[KimB]

That's kinda wierd, isn't it? If you can draw 5 million triangles per second, than you should be able to calculate far moe than 5 million vertices per second, no?

No. Since triangles typically are in a mesh and share vertices, optimized rendering will often average about one vertex calculated per triangle rendered.

 

[Shogmaster]

Aha. Rendering strips and the like. I see.

I'm beginning to lean towards the GoForce over the MBX now, thanks you guys' help. Looks like nVidia may have another winner.

I suppose that's not fair to MBX since we don't know which chip is more efficient as a mobile chip, but as far as actual game pics battle (as little as we have so far), MBX took one to the chin it looks like:
GoForce 4500

MBX

edit: Hold on..... on further inspection, maybe the shots of the car game on both is the same game (OGL ES version of Stuntcar Extreme), and it just looks worse on the MBX because it's not a direct grab.

 

[Simon F]

- Both support programmable pixel shaders? (GoF4500 definitely, not sure about BMX)

MBX doesn't have a pixel shader .... but, from early announcements, I wasn't convinced that GoF' had them either.

- Both provide hardware T and L (MBX Pro offers Vertex Geometry Processor option, and GoF4500 seems to have one built in)

All models of MBX offer a VGP and it is "built in". It's up to the customer to decide if they want it or not (based on a performance/silicon area decision).

MBX

That's an MBX Lite with no VGP.

 

[Shogmaster]

- Both support programmable pixel shaders? (GoF4500 definitely, not sure about BMX)

MBX doesn't have a pixel shader .... but, from early announcements, I wasn't convinced that GoF' had them either.

They list it explicitely in their specs page now.

- Both provide hardware T and L (MBX Pro offers Vertex Geometry Processor option, and GoF4500 seems to have one built in)

All models of MBX offer a VGP and it is "built in". It's up to the customer to decide if they want it or not (based on a performance/silicon area decision).

Still means that VGP is not always a given in an MBX set up while it's a given in a GoForce 4500, right? That's what I was getting at.

MBX

That's an MBX Lite with no VGP.

The 2700G, right? Only runs at like 60~80Mhz too I heard. I'd love to see full speed (120+Mhz) MBX Pro with VGP in a portable console like the Gizmondo (but focused more on gaming like PSP or DS). I can dream, right? I still dream of my XBoy....

 

[Ailuros]

It just says geometry transform engine for the record; I might be blind but I can't seem to find the "L" part of T&L.

Anyway the optional VGP for MBX can output AFAIK 4 MFLOP/s per MHz and is VS1.1 compliant. For the MBX PRO PowerVR claims up to 3 Million Triangles/sec (some vendors count their triangles differently) and it has both Super- and Multisampling support, according to a recent presentation from John Metcalfe. Judging from Elan and how past PC products behaved, I wouldn't be surprised if those would also get multiple lights compared to 1 light in relative terms "for free".


And it has also something I adore on ladies most:

http://www.powervr.com/news/Release/index.asp?ID=65

 

[Ailuros]

The 2700G, right? Only runs at like 60~80Mhz too I heard. I'd love to see full speed (120+Mhz) MBX Pro with VGP in a portable console like the Gizmondo (but focused more on gaming like PSP or DS). I can dream, right? I still dream of my XBoy....

I think the OMAP2 might have a VGP, not sure though it that's a MBX Lite or MBX.

System : MBX Lite @66MHz, no VGP, ARM CPU
Quake III Demo at QVGA resolution, VSYNC locked 30Hz sustained rendering

 

[Shogmaster]

Hold the phone!

Is that thing a PPC, a cell phone, has VGA LCD, and include the 2700G/MBX Lite? Holy mackleberry, does it cost like $800?!?

 

[Ailuros]

For 800$ I'd rather buy that one:

http://www.beyond3d.com/forum/viewtopic.php?t=16188

 

[Shogmaster]

For 800$ I'd rather buy that one:

http://www.beyond3d.com/forum/viewtopic.php?t=16188

I don't think it'll fit in your pocket.

Besides,if you're going that big, for $800 you can get a real laptop that runs Windows and all the apps that go with it instead of that thing.

 

[rake]

Hold the phone!

Is that thing a PPC, a cell phone, has VGA LCD, and include the 2700G/MBX Lite? Holy mackleberry, does it cost like $800?!?

That's the Intrinsyc Carbonado PDA reference platform, it's not a shipping product. OEMs should be leveraging products off this platform soon, but as yet the Axim X50 remains the only rumoured 2700G PDA product on the immediate radar.

More info on Carbonado here

 

[JohnH]

- Both support programmable pixel shaders? (GoF4500 definitely, not sure about BMX)

MBX doesn't have a pixel shader .... but, from early announcements, I wasn't convinced that GoF' had them either.

They list it explicitely in their specs page now.

They may list it in their specs but its likely that this is a marketing manipulation of the truth, the truth probably being that this is not a pixel shader by the definition that PC space has i.e. I don't beleive it has the ability to manipulate texture addressing programatically (a given for true PS HW). (I've even heard rumors that it doesn't even support dot3, but I'd be surprised if this was the case, but given the absence of a dot3 demo).

- Both provide hardware T and L (MBX Pro offers Vertex Geometry Processor option, and GoF4500 seems to have one built in)

All models of MBX offer a VGP and it is "built in". It's up to the customer to decide if they want it or not (based on a performance/silicon area decision).

Still means that VGP is not always a given in an MBX set up while it's a given in a GoForce 4500, right? That's what I was getting at.

The 4500 only appears to support transform and not lighting and is not programmable, so in some ways is really only comparible to MBX without a VGP!

One other thing the 4500 only supports 16 bit frame buffer, where as MBX supports "Internal True Colour" at 32 BPP, this means the 4500 rendering of multi layer translucency will be vastly inferior to the result on MBX.

John.

 

[Shogmaster]

Really interesting John! Thanks. I was confused because I thought that the 4500 was 40bit in color precision, but maybe that's just 2D output? Hmm.

I'm still worried about the 2 layer max multitexturing for MBX holding it back compared to the 4500. I can foresee a future OGL ES PPC game benchmark with multitexturing being taxing on the MBX.

 

[JohnH]

My understanding is that the 4500's texture blending operates at 40 bits, but anything written to FB will get dithered down to 16 bits, this means that any kind of translucent effects will suffer from the problems of multiple re/dithering passes which really can look quite unplesant.

I'd be surprised if only having two texture layer support will have a big impact on any titles targeted at this generation devices in these environments.

John.

 

[Kristof]

I talked to some NVIDIA reps at Mobile Content World 2004 where they announced the 4500 and can indeed confirm that they only support hardware transforms for geometry. Hence no vertex shader or even lighting acceleration.

Now if you check the CEDEC 2004 presentation about the 4500 slide number 9 and 10 they explain that traditional pipelines have a lot of stages that might not always be used and hence they introduce a "fragment ALU". On slide 12 they then go on to say that simple scenes do not require fog, blending, alpha test and even depth comparison for every triangle. Hence when they say programable shader could they actually mean that they conditionally implement fog, blending, alpha test and even depth comparison in their "shader" unit hence slowing down performance with each of these "fixed function" effects being enabled ? Also DOT3 is missing from their own tech demos (Atlantis etc) and spec sheet which is a bit odd... I asked the rep both these questions but he did not know... sigh...

K-

 

[Shogmaster]

Hey Kristof. Can you tell us if the MBX was even considered by Tiger Telematics for Gizmondo? It would seem natural for a British console OEM to check into native tech...

Was it that they didn't want to go for an integrated ARM core GPU combo, and that the 2700G was clocked too slow (from what I understand, 2700G is a .18 micron and only goes up to 80Mhz)?

As for MBX v 4500, it sounds like games written for MBX should look prettier (DOT3, better transparency FXs). MBX needs to be in a portable console!!

 

[Rolf N]

Anyway the optional VGP for MBX can output AFAIK 4 MFLOP/s per MHz and is VS1.1 compliant. For the MBX PRO PowerVR claims up to 3 Million Triangles/sec (some vendors count their triangles differently)
<snip>

So true.
"146 MTris/s on a Geforce 4Ti4600" officially assumed two things:
1)Everything is strips and fans -- this one's at least possible
2)Trianlge setup is infinitely fast -- this one isn't