44 replies to this topic

[dflemstr]

How much is known about the SGX 530? Is there a chance thats its an SGX 535 with 2 pixel pipelines turned off and a lower clock?

Wouldn't matter, since the driver is closed source.

But oh man, it would be wonderful if it wasn't and if we were able to utilize those pipelines (assuming, of coruse, that there actually *is* a 535 inside)...

Edited by dflemstr, 29 August 2009 - 06:27 PM.

[Kramy]

I would think the SGX 535 would perform similarly to a 6200 LE/TC, with programs designed and optimized specifically for it.

In other words, graphics at the level of KOTOR could in theory be possible.

This is mainly due to most OpenGL/DX computer games using 50% of their processing power for the basic stuff, and 50% for some fog or w/e. Basically, a feature deemed necessary saps away the performance, and with no room to upgrade your GPU the developer can't make that call.

But we have the SGX 530, which is half as fast?

[Enverex]

It's perfectly possible to compare speeds to desktop cards, simply run games that run on both arches and compare numbers, that'll give you an idea and that's what the original poster was looking for. FPS is always comparable to FPS.

Nope, you have to take screen sizes and memory constraints + memory speeds into consideration if you just go by FPS. FPS is a horrible performance assessment tool, and you should never use it. This is not just my personal opinion; there have been multiple scientific articles about it

That's assuming the same situation for both cards (same quality settings, screen mode, etc). 15fps in a game is 15fps on any other device. Getting 15fps on one card that is "theoretically better" than another card wont make it any more playable, it's still 15fps. That's why you bench multiple different games that use different functions to get an overview of how it operates doing different things rather than using a single game as a reference. Therefore, for the end user, FPS is an excellent benchmark as it tells them how well it'll be able to run that app (and similar other ones).

[Calmatory]

It's perfectly possible to compare speeds to desktop cards, simply run games that run on both arches and compare numbers, that'll give you an idea and that's what the original poster was looking for. FPS is always comparable to FPS.

Nope, you have to take screen sizes and memory constraints + memory speeds into consideration if you just go by FPS. FPS is a horrible performance assessment tool, and you should never use it. This is not just my personal opinion; there have been multiple scientific articles about it

That's assuming the same situation for both cards (same quality settings, screen mode, etc). 15fps in a game is 15fps on any other device. Getting 15fps on one card that is "theoretically better" than another card wont make it any more playable, it's still 15fps. That's why you bench multiple different games that use different functions to get an overview of how it operates doing different things rather than using a single game as a reference. Therefore, for the end user, FPS is an excellent benchmark as it tells them how well it'll be able to run that app (and similar other ones).

Except that you would need the same hardware for both machines in comparison. Exactly the same CPU, same RAM chips(crucial with integrated GPUs), same software suite. Everything should be the same except the GPU.

It wouldn't make much of a difference if one slapped dual Nvidia GTX 285's to Pandora, FPS rates wouldn't be going up because the actual CPU is holding back. For sure less than a 1 GHz ARM based CPU isn't going to be faster than 1 GHz x86 based CPU(AMD Duron(Spitfire), 950 MHz), which held me back with my old GeForce 4 MX 4000(NV18b core, exactly the same as with GeForce 2 but with few tweaks and increased clock speeds).

In other words, I'd say that IF the GPU is anywhere near GeForce 2 speeds, it will be way faster than it "should" be. In a sense that the CPU will be the bottleneck in graphics heavy tasks.

A reminder, Pandora uses 800*480 resolution, which means much more raw power per pixel than with general PC's(1024*768 was quite the standard back in GeForce 2 days).

The problem/bottleneck with the SGX will most probably be the memory bandwidth rather than the raw GPU power. But yeah, I have no clue about the chip. Google says absolutely nothing about it really.

[Enverex]

I agree with that, you would need a "same spec" base machine to compare it if you were benching the whole machine. What I meant was that if you theoretically had the same base machine (that being the Pandora itself) then where would it clock. That's pretty much impossible to work out though. The memory will be an issue due to it being shared and not "GDDR3" backed with a multi-core CPU like everything else these days but hopefully it'll be good enough when used to its full potential.

[Kramy]

A reminder, Pandora uses 800*480 resolution, which means much more raw power per pixel than with general PC's(1024*768 was quite the standard back in GeForce 2 days).

384000 pixels, versus 786432 pixels. More than twice as many in 1024x768. I really do think GF6200 level graphics might be possible, if a talented developer made an optimized engine.

[PhonicUK]

Given the performance we've seen in Quake 3, I'd peg it at around the speed of a GeForce 2 Ti or a GeForce 4 MX

The GF2/4 of course had no shader units, so I'm going purely for triangles/sec and texture fill rate. A GeForce 5200LE might be what it can manage at a push (The 5xxx had SM2 support)

[Enverex]

A reminder, Pandora uses 800*480 resolution, which means much more raw power per pixel than with general PC's(1024*768 was quite the standard back in GeForce 2 days).

384000 pixels, versus 786432 pixels. More than twice as many in 1024x768. I really do think GF6200 level graphics might be possible, if a talented developer made an optimized engine.

Doesn't really work that way, upping the screen-res generally doesn't cut or increase your framerate in a linear fashion...

[dockthepod]

A reminder, Pandora uses 800*480 resolution, which means much more raw power per pixel than with general PC's(1024*768 was quite the standard back in GeForce 2 days).

384000 pixels, versus 786432 pixels. More than twice as many in 1024x768. I really do think GF6200 level graphics might be possible, if a talented developer made an optimized engine.

Doesn't really work that way, upping the screen-res generally doesn't cut or increase your framerate in a linear fashion...

Depends if you are fragment bound or vertex bound (or cpu bound). Most old skool games didn't have very much per-pixel cost so frame buffer size isn't a big difference. Many games these days are fragment bound.

[Exophase]

Calmatory, you're focusing on the wrong metrics. A tile based deferred renderer (TBDR) like SGX scales very differently with respect to both memory bandwidth and fillrate (texture accesses, per-fragment operations) than an immediate based renderer (IMR) does. Compared to an old DX6 or DX7 level card like TNT1, TNT2, or GeForce 1, you could say that SGX 530 might not work as hard but it works much more smartly. TBDR makes it so only the top-most opaque pixel and whatever translucent pixels are on top of it need to be rendered, which includes all of the fragment shading pipeline. What this also means is that you don't normally need depth or stencil buffers stored along the framebuffer, so they can be kept in very fast on-chip SRAM, and the framebuffer is cached per-tile allowing for quick bursting and aggressive prefetching. Even with alpha blending every framebuffer pixel has to be written only once (fire and forget).

So you should be able to see how a platform like this gets away with needing much lower bandwidth and pixel operations per second. About the only thing that needs to be fast are the depth comparators for performing the early-Z removal, which is why there are 8 or so of them. As an added bonus, you also get very high depth precision (32bit floating point, I think using 1/w) which helps prevent z-fighting.

The shader pipelines also look weak on paper since there are only two of them and they only support single issue 32bit (or maybe 40bit, I'm not altogether sure about this) operations. But this is mitigated by supporting 3/4-way SIMD over 10bit fixed point color formats, allowing color operations to still be vectorized. Texel blending/fogging/per-pixel lighting/etc operations will tend to dominate over per-vertex operations that need higher precision, and the reduced color range is perfectly acceptable for a device such as this, especially when you're comparing it to old non-HDR graphics cards to begin with. The efficiency of the USSEs is also boosted by supporting vertical multithreading (single-issue SMT), allowing very fast thread switching automatically to hide latency. Old fixed function archs were probably already designed to hide latency but this allows for much more effective throughput of shaders than would be possible otherwise.

There are of course some gotchas: you have to avoid alpha testing and multi-pass rendering to really use the renderer effectively. These things still work but they take a big toll on the efficiency. But if a game plays nice then it can make the rather low clocked/narrow platform go surprisingly far.

If you want a realistic comparison then look at the graphical quality of Sega Dreamcast games, and imagine something at least 2x stronger and with much more modern features/flexibility. Also imagine something that can support at least a few times as many polygons on screen.

[darkblu]

Radeon 9000 is the only tough one. If you limited the SGX to doing things exactly as the Radeon does and no more then I think the Radeon could probably win, but it'd be so crippled that it's really far from a fair comparison. Given the lower resolutions expected and the TBDR I think that even if the SGX has less brute force power it can still probably deliver better looking games without much problem.

i think there's no need for the probabilistic part in the bold. SGX is unified shader, r2xx is not. while the SGX may reach as extrema the vertex and the fragment performances, individually, of the R2xx, it has little chance of maintaining them simultaneously. i'm saying that as a RV280 home user - that chip can happily crunch some ~2M verts/s worth of phong-blinn with a single light source, while simultaneously painting a 1024^2 viewport with a fragment shader.

[(naw)mcx]

If you want a realistic comparison then look at the graphical quality of Sega Dreamcast games, and imagine something at least 2x stronger and with much more modern features/flexibility. Also imagine something that can support at least a few times as many polygons on screen.

So you're saying that we can get around Dreamcast quality games, graphics wise, all things considered.

I thought the Dreamcast rivaled the PS2 in graphics, beat it in places!
(of maybe I'm just being nostalgic)

[bustaballs]

If you want a realistic comparison then look at the graphical quality of Sega Dreamcast games, and imagine something at least 2x stronger and with much more modern features/flexibility. Also imagine something that can support at least a few times as many polygons on screen.

So you're saying that we can get around Dreamcast quality games, graphics wise, all things considered.

I thought the Dreamcast rivaled the PS2 in graphics, beat it in places!
(of maybe I'm just being nostalgic)

If the thing can run Doom 3 (minus some graphical features with low resolution), then the graphical abilities would easily surpass Dreamcast level. I think it could rival a Radeon 7000 or maybe 8500. I'm also assuming it could rival those Intel GMA chipsets.

Edited by bustaballs, 31 August 2009 - 09:49 PM.

[Phawx]

Well the Intel GMA 500 is an SGX 535, which is a faster version of the Pandora's SGX, the 530.

And here is the benchmark for the GMA 500 when matched with an x86 atom.

The process seems very large. Using 13 Micron with the chip test. Whereas the SGX 530 in the Pandora is 65nm. However, it probably only gives us lower power consumption.

However, we might have faster ram then what was tested on these Benches.

However, I don't think looking at these benches is fair. I mean, we've already seen Quake 3 running at 800x480 with medium settings running quite nicely. So we have to be able to get at least, comparatively, 6000-7000 points in 3D Mark 2001.

The test didn't run on this page. Honestly, The hardware is nice for how much power is being used. Also it's a very deep feature set, so honestly unless a team of people can get coordinated to create something specifically for this chipset, I don't think we will see exactly what she can do.

Edited by Phawx, 31 August 2009 - 10:07 PM.

[wermy]

Well the Intel GMA 500 is an SGX 535, which is a faster version of the Pandora's SGX, the 530.

Hmm... If this is true, would a driver for the GMA 500 be useful in getting full OpenGL 2.0 on the Pandora? Does such an open-source driver for the GMA 500 exist?