Hi I will be glad if you help solve the problem.
I've bought iMac (27", Retina 5K, fusion drive 1 tb), all its parameters are suitable for AC23, but rendering for some reason is too slow. Do you know the probable reasons?
"Too slow" is a bit subjective. What did you expect or compare the rendering time to?
The speed is highly dependent upon the rendering engine settings you have chosen... which, for Cinerender, is a long discussion covered in many threads over many years in the Presentation/Rendering forum.
If you are using Cinerender, then the number and speed of processor cores and quantity (and speed) of RAM will matter... as will the use of the fusion drive (vs a pure SSD). If you are using Twin Motion, then all processing is on the graphics adapter and the speed is dependent on which one you have in your configuration.
One of the forum moderators • AC 26 USA and earlier • macOS 12.6.1, iMac Pro 10-Core, Radeon Pro Vega 64
Quite likely. I am pretty sure I have seem ACs RAM usage go over 16gb on my system while doing relatively basic renderings of a large model... Look to see if AC is using Virtual Memory when you render? ie. Does the RAM usage go over 8gb.
AC22-23 AUS 7000 Self-taught, bend it till it breaks. Win10 | E5620 x 2 | 24GB | K2200 RIP PSU Win10 | R5 2600 | 16GB | GTX1660