Workstation Graphics: AGP Cross Section 2004

Shader Analysis

To open this section, we would first like to start by stating that we wish we could have found a suitable benchmark to test GLSL performance in a similar way that Shadermark manages to test HLSL performance. OpenGL fragment shading performance under which we ran the demos on the Wildcat Realizm part is much higher than its DirectX pixel shading performance under Shadermark. In fact, even in playing with ATI's own Rendermonkey, it was apparent that the 3Dlabs card handled GLSL shaders better than the FireGL X3. Since OpenGL is the language of the workstation, it makes sense that the workstation is only where 3Dlabs would focus its efforts first, while ATI's consumer oriented approach would lend it the clear upper hand in DirectX HLSL benchmarks like Shadermark.

But DirectX and HLSL is still a very relevant test and is supported on all these cards. Of note is the fact that Shadermark would not run PS 3.0 code on the Wildcat Realizm. Shadermark chose to use the PS 2.0a path, which supports a wider range of features than the PS 2.0b path used for both of the ATI cards. Shadermark has been known to be very picky about code paths that it runs, and it's possible that there is an issue with the fact that this 3Dlabs part is simply not on the Shadermark map. But part of the point of HLSL is that the code should still run with no problems. We did get the option of creating an A2R10G10B10 hardware device on the Wildcat Realizm in shadermark where no other card presented such a feature. But let's take a look at what the numbers have to say.

Shadermark v2.1 Performance Chart
	GeForce 6800U	Quadro FX 4000	Radeon X850XT	FireGL X3-256	Realizm 200
shader 2	893	596	996	731	41
shader 3	736	493	735	531	28
shader 4	737	493	732	531	28
shader 5	669	448	608	438	16
shader 6	680	467	735	530	28
shader 7	631	417	654	485	23
shader 8	383	255	406	301	11
shader 9	894	630	1263	977	55
shader 10	807	553	819	617	43
shader 11	680	467	694	509	27
shader 12	446	319	263	186	13
shader 13	383	276	361	252	13
shader 14	446	316	399	280	18
shader 15	328	244	285	206	21
shader 16	314	224	336	244	8
shader 17	425	309	429	315	8
shader 18	56	39	40	30	2
shader 19	180	134	139	99	6
shader 20	57	41	47	33	3
shader 21	90	63	-	-	-
shader 22	119	96	204	154	14
shader 23	133	106	-	-	15
shader 24	80	67	143	108	118
shader 25	97	69	118	86	6
shader 26	93	67	123	89	6

Not surprisingly, the consumer level parts are the top performers here. The Quadro FX 4000 and FireGL X3-256 don't do a bad job of keeping up with their desktop counterparts. However, the Wildcat Realizm 200 puts in a very poor showing. In addition to this, the Realizm didn't render many of the shaders correctly. Granted, the Microsoft reference rasterizer does not create correct images, but they are close in most cases. Shadermark generates MSE (mean squared error) data for screenshots taken and compared against reference images. Both ATI and NVIDIA hit between 0.5 and 1 in most tests. There is not a single shader rendered on the Wildcat Realizm 200 with an MSE of less than about 2.5. Most shaders show very clear image quality issues.

With the image quality of Wildcat Realizm in Doom 3 and Half-Life 2 being dead on with the other cards, and performance under Half-Life 2 not being as bad as we expected, we have to wonder how much of the issues with Shadermark would translate into actual applications. And by applications, we mean any application that allows the creation and/or visualization of HLSL or GLSL shaders. DCC workstation users are becoming more and more involved in the process of creating and designing complex shader effects. In order to maintain a firm position in the future of DCC workflow, 3Dlabs will need to assure smooth, accurate support of HLSL, no matter what the application running the code.

We will continue to evaluate programs for benchmarking GLSL performance. Through observation, the NVIDIA and 3Dlabs parts have an advantage over the ATI parts in GLSL performance. Unfortunately, we don't have any quantitative tests to bring to the table at this time.