Actually reflections are currently one of the single most demanding features in terms of render time - even complex populations like trees, grass, etc. will tend to be notably faster. So since this image consists almost entirely of rough and reflective water (the more rough the water, the slower the render time due to interreflection), it is almost a "worst case scenario".
The points that others made are also very valid and important to fully understand. It would help to know more about the particular settings used, but above all you don't want to assume that the settings someone decided on for their render are necessarily sensible. Just because it took him 170 hours doesn't mean that was what was necessary to achieve this level of quality, and TG can't be held responsible for someone else's poor detail decisions. There are many detail-related settings in TG2 that have little or no effect in certain situations. A fine example is GI - in this case GI was probably almost unnecessary and if it was above 1 for either Relative Detail or Sample Quality it shouldn't have been. It simply would not show any improvement. Likewise with cloud samples. I do see clouds in the image very faintly, but they are so subtle and lacking in volume that samples of 16 or at most 32 really ought to be fine.
Another extremely important and misused setting is the "ray-traced shadows" in the quality tabs of both Atmosphere and Cloud nodes. These almost *never* need to be turned on because they only affect the appearance of atmospheric rays *from* the terrain and shadows *onto* clouds *from* the terrain. In other words they are responsible for interactions between terrain and atmosphere. In 90% of scenes there simply is no interaction so these can be left off. They increase render time by a great deal so they should really be avoided unless absolutely necessary. Note that there is a current known bug where the sun can "shine" through the terrain when at a low angle and this can only be fixed at the moment by turning on ray-traced shadows in the atmosphere, however this will of course be fixed in the future and this setting won't be required as a workaround.
The bottom line is that there are so many variables and so many easy ways to setup unnecessarily long renders that one really shouldn't judge likely render time by someone else's results, especially without knowing all detail settings and evaluating the scene yourself for their sensibility. It will take some time for people to better understand the detail settings in TG2 and how to use them to maximum effect. The most important thing to keep in mind is that simply increasing all sliders to maximum and turning on all "quality" options is *not* the best approach and is usually not necessary. Start conservatively, do lots of crop renders to test your detail settings, and increase detail in reasonable increments. You'll save yourself a lot of render time on the final images.
Finally in regards to the CPU speed, your 2.4Ghz means a lot more if it's either an Athlon XP/64/X2 or better yet a Core 2 Duo. The only CPU that reached 3.6Ghz was a Pentium 4 variant, and they are unfortunately not the best for TG2 rendering speed. Not to mention if you do have a Core 2 Duo or other multi-core CPU you can expect a huge reduction in render times when the rendering system is multi-threaded and able to take advantage of both cores. Right now it only uses 1 so it's almost half the speed it could be from that optimization alone. There are also many other optimizations planned that should ultimately result in very significant speedups. Going from 170 hours to 20 hours is almost a factor of 10 and that's not really a realistic expectation, but I would not be surprised to see some scenes rendering 3-4 times faster on dual core systems by the time TG2 is released.
- Oshyan
