Thanks for your thoughts 
I have now also tried a Peter Guthrie HDR image from my work computer and that is also just in 72 dpi and actually smaller resolution then the first HDR. I still get the same noise though… Must be some settings that I don’t understand yet in FluidRay RT. Ah, jewellery sounds cool, and small. I work with interior renderings and furniture design, and up until now I have been rendering with Vray 2.0, but I loath all the tons of settings and tweaks needed to produce a good rendering. Therefore FluidRay RT seems like a really good alternative. I just need to figure out how the settings work, and if I can use distributed rendering on the servers at work as well as queuing up multiply renderings.