I have a 2060 with 12 gig vram. I usually use 2048 for optic rendering. It works well with the size images I render. Most are less than 2k. When I run out of vram and have to switch to cpu rendering I use 64 for the bucket size. My test show that to be the best for me though 32 and 128 aren’t much slower. 

---

Available on Amazon for the Kindle E-Reader Monster of the North and The Shimmering Mage

Today I break my own personal record for the number of days for being alive.
Check out my store here or my free stuff here
I use Poser 13 and win 10