I'm glad it's working for you with the iMac Pro 1,1. That's a Xeon based system, so I didn't think that would work.
Your disk speed is good if it's a mechanical hard drive. As far as your benchmark, I'm guessing you are keeping your CPU speeds stock? If so, I think that's right. I'm overclocked to 5.2 all cores.
I'm not going to be able to get around to it today, so I'll have to resume messing with it next weekend. It should work with MacMini, not so much with the iMac, because I don't think any of those models came without a discreet graphics card (which makes the iMac Pro even more of a head scratcher, lol). Heck the iMac Pro came with a Vega graphics card. I might have to try that with my normal setup and compare it.