Why is the Recommended Configuration only 4 Cores and 8GB RAM on a 28 Core, 192 RAM Mac Pro?

Why is the Recommended Configuration only 4 Cores and 8GB RAM on a 28 Core, 192 RAM Mac Pro? I'm starting to wonder if this is all Parallels can handle? I bought this new workhorse Mac Pro to assign more cores, but it doesn't seem to go any faster than the Macbook Pro I used.

To Test this, i ran an operation in Excel using the recommended configuration and it took 2min 10 sec. with the 4 Core, 8GB ram. I then made a manual configuration of 20 Core, 128GB of RAM. The speed went down to 45 seconds.

On both tests, it only operated with 1 thread per Core, (4 threads and 20 threads) whereas when I once used Bootcamp it would multi-thread for a total of 8 and 40 threads. Anyways, i thought I'd do better on this. Curious to hear other's experiences when running Parallels off a 2019 Mac Pro.

 

OK, now I'm convinced these answers are coming from Bots and not real people. 2 for 2 on reference to articles that in no way answer the question. The link provided is for "Parallels Tools manual installation in Linux virtual machine" and not Virtual Machine Limitations. However, it is in fact what was written in the [correct] article that brought me to my question above, which is: Why does parallels recommend 4 cores and 8GB of RAM when your superior product [parallels pro] allows you to do more? Its like you're telling me to upgrade because it will give you all this additional speed while at the same time telling me I'm NOT going to get the additional speed.

 

Hello Kevin, we are sorry for the performance issue you are facing. Irrespective of the additional memory you can use only 50% of your macs hardware resources, As both the mac and the virtual machine both run parallelly. We have made sure that by allocating only 50% of the mac hardware resources to the virtual machine, You can use the Mac OS and the virtual machine with stable performance.