4 ms·

It is you that is off by several orders of magnitude. 4GB/sec is 10^9 random floats per sec, and using your 118 random numbers per sample that'd be 8.5 million

• magicalhippo 6y ago
  Well that was certainly embarrassing. On the other hand I overlooked that in my test scene it samples the lights at every vertex, and I forgot it had textures which needs at least 2 coordinates per vertex. So it needs at least 10 * 32 * 2 = 960 random values for that. I also recall that we tried MT but found a quite noticeable impact on speed compared to what we had, and on the PGC performance page MT is listed in the tens of GB/s. Perhaps our implementation was considerably worse though, I can't recall us testing it alone like that. As I mentioned though, that renderer was more about physics and fidelity. Typical render times for even a preview would be a minute, for final single-frame stills tens of hours to several days on a single computer was common. For animations you don't have that kind of time, so you need a orders of magnitude more samples/sec.