I seriously doubt the CPU is your problem.
What kind of audio interface are you using? Is it what’s on the motherboard, or is it a nice pro audio interface with true ASIO drivers?
Something’s not right. I ran dozens of simple sampler tracks with an old Phenom II generation cpu with just 4 cores, and that’s with DDR2 memory and SATA2 generation drives. Sometimes I needed larger ASIO buffers (512k or larger) but it got the job done.
Run latency monitor without Cubase running first. See if that gives any hint of a driver or something that might be doing interrupts or causing a bottle neck. Common culprits are network interfaces. Here’s a quick over-view of how to run some tests and make adjustments.
Windows: How to set-up and optimize a Digital Audio Workstation – Steinberg Support
I once had some PNY SSD drives that use drivers that would handle massive chunks of data pretty quickly (they were really fast at straight up loading/saving large files from memory), but would always do an interrupt between each data chunk, and this was really BAD for my DAW apps that perfer to ‘constantly stream data’. I stopped using those PNY drives for anything that needs to stream and all was well thereafter. As odd as it seems, I actually got better A/V d2d performance from old platter drives than those PNY SSD units.
Anyway, my point isn’t that your drives are bad…but rather, some driver in your system might be causing the problem. If it’s a network driver (pretty common), then disabling the interface when you want to use the DAW can fix it. Or, you might get and find a different driver that doesn’t do interrupts the same way.
With Cubase 10 or later running, you can run a real-time latency monitor on all the mixer channels. That can help track down individual plugins that might be causing a problem.
How Cubase 10 Can Solve Your Latency Problems Once And For All : Ask.Audio
Also, what instrument(s)/plugin(s) are involved here? I do have some SONIVOX stuff here that just refuses to run on AMD (including my Ryzen 9 3900XT OC at over 4ghz) unless I use HUGE ASIO buffers up to 4mb (and even then it’ll glitch until I’ve played a few times and gotten more of the samples cached into memory). I don’t know what they did with the sample encryption and all for those plugins, but I’ve never been able to use them on AMD builds.