NVIDIA Quadro DDR

SPEC’s GLperf

SPEC’s Glperf 3.1.2 is a good, low level, easy to use OpenGL test tool that one can use to look at how graphics card/systems handle specific OpenGL functions.  This tool was used to investigate the tri-meshed strip performance of the cards under review.  Tri-meshed strips are one of the most efficient ways of presenting geometric data to be processed in that it reduces the compute load for either the GPU or host CPU depending on the card’s design.  GLperf is driven by a script and the execute fragment for the one used for initial test was:

TriangleStripTest {

(UserString printf("(%s,flat)",
                  ExecuteMode))
(ExecuteMode Immediate)
(DepthTest GL_LEQUAL)
(ObjsPerBeginEnd    4)
(Size from 1 to 512 step 100%)
(ShadeModel GL_FLAT)

}

This test script generates and plots flat shaded triangle strips with the triangle areas stepping from 1 pixel to 512 pixels. The test output was put into chart form:

This chart shows triangle performance (triangles per sec.) as a function of pixels per triangle. The two main constraints on card performance is evident in the plot’s shape.  A card’s peak geometry T&L rate defines a horizontal line and the card’s peak fill rate locates the diagonal line representing constant maximum fill rate.  On the flat horizontal portion of the curve the card is triangle rate limited and on the sloped portion of the curve it is fill rate limited.

The Quadro DDR has the best performance.  The GLoria II (Quadro SDR )  and the CL Annihilator (GeForce SDR ) have almost exactly the same performance on this test and appear as a single line on the plot. The AGP version of the GVX1 is better than the PCI version.  Since the VX1 and the TNT2Ultra use the host CPU for T&L, their peak triangle rates were about the same.  The value of an on card GPU is clearly seen in this chart: the GVX1, GeForce and Quadro are clearly faster on peak triangle rate than the other cards that depend on the host CPU.

The maximum fill rate for the Quadro DDR was about 65% better than for the Quadro SDR or GeForce SDR, this fact clearly shows the benefit of the reference card's DDR SDRAM.