We've known the specifications of the 3DS's GPU even before the system was released and not much has changed since.
GPU Name: DMP PICA200
Frequency: 133 MHz
Polygons per Second: 15.3 Million (according to specs sheet, at 200 MHz)
Fillrate (Gigapixels per Second): 0.8 (according to specs sheet, at 200 MHz)
GFLOPs: 4.8 (according to specs sheet, at 200 MHz); 3.192 (at 133 MHz, rough calculation)
Resolution: 400x240 (2x400x240 in 3D Mode)
Long story short, the GPU is weaker than that of the Gamecube (6.5 GFLOPs), however it supports much more contemporary rendering and shading technologies.
My bad, I'll adjust that, I got the frequency mixed up with something else *grabs calculator again*. I also corrected the Gamecube's Flipper data.3Dbrew states the GPU clock speed at 268MHz. So the raw numbers you stated, 3DS could possibly top that if applied with its clock speed.
Anyway 3DS is weaker than the Gamecube. Using lower screen res, its underpowered GPU doesn't need as many pixels, combined with modern GPU rendering it can make games pretty as Gamecube to the eyes.
however it supports much more contemporary rendering and shading technologies.
That was my point - it has less processing power (obviously) but supports more contemporary libraries. OpenGLES 1.1 is listed in the specs sheet of the PICA200, but the chip does indeed have other features going beyond the standard set (dubbed Maestro Technology) such as per-pixel lighting or gaseous object rendering, among others. I'd assume that it's a custom design to some extent, so I wouldn't be surprised if it also supported a degree of OpenGLES 2.0's feature set, but that's not saying much, especially in comparison to contemporary smartphones. It's not exactly a powerhouse, much like the DS wasn't in its days.smea was doing a bit of work on this and 3ds 3d systems in recent weeks. You will have to await more of his work (there is a bit going up on github but it is more coder focused than something like gbatek) for proper discussion but it seems the base hardware resembles opengl es 1.1 but the software/fiddling has a few 2.0 like things bolted on (including said shaders which 1.1 mostly lacks).
With that and comparing it to the GC.... I reckon you could justify hiring people that really know 3d to work on the 3ds. However the 3ds has been somewhat outpaced by its competitors so eh really. I guess it could rub shoulders with some of the GC library but I am not going to hold my breath, and I am not likely to end up calling it "little GC" like I might have called the GBA/DS "little SNES" and the GB "little NES".