Windows 10 on Windows 10 with Core2Quad?

[Barryfrn]

I'm attempting to run Windows 10 (with 4 GB RAM) on a Windows 10 1909 host using an ASUS P5Q PRO motherboard with an Intel Core2Quad 9550 processor (running at 3.61 GHz) and 8 GB of RAM, utilizing VirtualBox Version 6.1.6 r137129. However, the performance is extremely poor. Even though the host is showing usage of only 2 cores at maximum, performance is significantly slower when utilizing all 4 cores compared to just using 2 cores. Even when reducing CPU usage to 75%, the host only utilizes 50% of its power, resulting in extremely slow performance for the guest OS. The same issue persists when attempting to use 3 cores. It feels like the performance ratio between 2 cores and 4 cores is approximately 20:1. Currently, utilizing more than 2 cores is impractical due to the lack of performance improvement. This issue persists regardless of whether it's a fresh install or if I adjust the number of cores on a previously installed virtual machine. Could you please investigate this matter, as I require the power of more than 2 cores for my tasks.

[BillG]

That sounds about what I would expect. Allocating more than 2 cores of a 4-core host is usually a waste of time.

IF you need that much processor power, you will need to run the program on the host. You don't have enough processor power on the host to share with a vm. When you run a vm, you are in effect running two PCs on a device designed to run a single PC.