Hello. I'm using OctaneRender plguin v29.14 and I've a RTX 4090 running Windows 11 23H2.
I picked unique region at Photon Tracing kernel@50diff and @60spec depthes and @radius 0.01 and... I got... bit more than 1M spp* (= 1,028,776 spp*).

Woww!

Because I don't know how do I increase the number of spp* from 1M for region picked since OR v3 (2016):
NOTE: This black region means lock. Because this FREE extra requires you can buy a big rendered image about PSOR prism@diamond on glossy ground for eliminate any black - check OP -
viewtopic.php?f=5&t=81921.
* - it is samples per pixel as S/px.