This is becoming an FAQ. Somebody should type up a formal answer discussing all the pertinent factors- it would be helpful to people [I suspect I am volunteering]. When you say performance is less than you want, what is it that you want? Can you elaborate?
You don’t need inside track developer information to understand the architecture and performance of an engraving program. They are all similar, for example, LilyPond as well, due to the nature of musical notation. In a nutshell, it is an unavoidable fact that at some point the layout engine must do things sequentially. like it or not, so there is not a great deal of parallelism one an apply. Having a snappy CPU aids overall performance, but overclocking is not worth it for Dorico, with the attendant heating and cooling costs and reduced longevity of the CPU. An SSD is only good for fast saves and loads. Obviously does not affect what’s happening while in write mode etc. VST’s are another matter, and not to do with Dorico. If you have a lot of VST’s or a very large sample library you’d be advised to have 32 or 64GB RAM to fit it all in but going further than that does not seem to be necessary. Once you are in the 128GB RAM territory you are also in gaming machine pricing territory.
I’m a Windows 11 user and my i7-9750H CPU is more than up to the job, and the Gigabyte Aero notebook it runs on just flies, 32GB RAM, 2 SSD’s. While I do not write orchestral scores I do write VERY complex modernist notation, for what it’s worth. I am very happy.
As to what is ‘absolutely ideal’ I think this is a slightly meaningless term. What is ideal for one is not for another, especially considering people generally use their computers for other work as well, for example DAWs, video production, software development etc. Similar to, what is the absolutely ideal automobile?
If you mean what is a really high end machine good for musical scoring, you could look at the Apple Mac Studio, but they are not very expandable, sadly. As an exercise I just optioned up a Mac Studio with the sort of specs you were discussing and it comes out at USD$6998.99. [Don’t you love the 99 cents…] For me, for scoring, that’s not a good value proposition unless you have a boss who will buy it for the company.
Also note that over time with the marvellous frequent update releases of Dorico there are constant performance enhancements, such as the recent one relating to ‘select all’.
I’m sure lots of forum users will chime in here with specs of their machines that they find adequate as well.