PCIe Performance with X299 Motherboards slower

[macattackjack]

Hi

I have been trying to upgrade from my x79 Asus motherboards and MB/CPU to a newer system. This is a project that I've been working on over the course of several months now.

The old boards work with Catalina, but the Rampage IV Gene has a 32GB ram limit.

The problem is the the PCIe performance is utter {censored} in the new boards.

My current system is a Asus Rampage IV Gene with a i7-3820 4 core cpu with 10.5 MB of cache. With my old system, with everything installed and working, the CPU meter for my audio software was at 4%

I tried a Gigabyte z390 gaming motherboard and i9-9900k combo and the meter shot up to 20%. In exploring that, I was told that it could be two things: The number of PCIe lanes in the CPU and/or the L3 cache in the CPU.  The 9900k has 16 mb l3 cache and only 16 PCIe lane.s

So I got rid of that combo and got a EVGA X299 Micro MB and a i7-9800x socket 2066. the 9800x has 16 MB L3 Cache and 44 PCI-e Lanes

Using the EXACT same SSD that I used on the Z390 combo (It required no mod to work with the X299) produced a the same CPU performance meter reading of 20%

I have the latest bios for the motherboard. I've tried turning various settings off and on. Above 4G, MSR lock, etc etc. I have even tried the PCIe settings in the bios.

Both new CPUs give 1 MB per thread, where as the 3820 has extra L3 cache memory. But I tried a 4930k CPU in the Ramage IV Gene and the cpu performance meter was 4% as well.

It seems like a lot of the new cpus are severely lacking in L3 cache and PCIe lanes? Is the current trend to give less throughput in the PCIe?

Any ideas about why the performance sucks so bad? Or what I can do about it? I have spent hours trying to get this to work.

Thanks

Edited April 20, 2020 by macattackjack