MP 1,1-5,1 Advice please?

[quad121]

The question is I have OS Mojave installed. I was looking at also installing Windows as well as Catalina(BigSur).
In 1 of the 4 sata bays I have the original install of Mojave and the other drive has an old version not being used as such High Sierra.
I have also a HighPoint 7101a which has the main OS (boot) Mojave and 2 nvme’s in a raid 0 used as a scratch. There is a spare way for a 4th nvme drive.
In my understanding, using Open Core to install Catalina on the 4th nvme? Or would it be better to install on the slower Sata drive?
Also how would you go about installing Windows?

Any advice would be greatly appreciated

 

[haralds]

It is much simpler to install Windows on a non-raided drive on one of the standard controllers.
I would install macOS on an SSD, not a spinner. Dramatically different performance.
For Catalina using the DosDude patcher is simpler than OC. It does not prevent you from switching to OC.
Look at some of the other postings on compatibility issues with newer drives larger than 8TB. Drive mount holes may be in different locations and there is an issue with a rest pin not allowing the drive to spin up on reboot. I had one of them and covered that pin with tape.
Since you want performance look for CMR drives, mine was SMR and definitely not as responsive. I have moved mine to my TimeCapsule for secondary backup in addition to my NAS.
Overall I have moved to depopulate my cMP shifting most storage to the NAS as part of a slow migration to my PowerBook M1.
BTW, years ago I ran into an issue where more than 6 drives in the cMP stopped enumerating reliably. This happened after one of the firmware upgrades adding APFS support. I used to have 9 internal drives (4 SSD on one NVME in addition to 4 spinners.) After periodic fiddling (pulling all drives, reset SMC and PRAM, and then building up drive by drive with reboots) I finally just gave up on it.
My currents setup has an SSD with Mojave and Windows in slot 1, 3 spinners, an NVME for Catalina (can boot with boot-args="-no_compat_check"), and a card with an SSD for Big Sur. Although the Catalina NVME averages triple the performance of the SSD on an OWC card, there is little perceived difference in real life. Big Sur uses OC and latebloom, which often requires a bunch of reboots to get it going.
Note that I rarely boot Windows natively and mostly use it with Parallels. Running Windows as pure VM (instead of booting BootCamp) has advantages in reducing disk space requirements and allowing VM sleep. Not that Parallels supports cMP on Big Sur, VMware does not.
For most tasks, the PowerBook M1 (16GB/2TB) is as fast or more responsive than the cMP. Xcode compiles are similar, Final Cut and Logic Pro beat the cMP hands down. operation is MUCH smoother. I am working my cMP withdrawal by having both hooked to my Dell U38 monitor. I have not used the cMP for several days and am just fine.

 

[quad121]

Many thanks Harald for all your information and time.
On what I’ve read it does state your best running ‘dosdude1’ or ‘OC’ not on a nvme drive.
I have at the moment in the macs sata sledge 2 spinners which would probably be worth changing to SSDs so as I’ll be looking for some sata 2 drives