Any reason for the 64gigs of Memory? The new 10k ssd's are in their infancy, I'd wait a year or so before diving in.
Otherwise that is a solid build!!!
I have had this problem ever since I started using Steam and my back log began.. Then you get the giant game list from Epic, Xbox Game Pass and PlayStation Plus... I usually just default to some stupid game that is mindless and easy.
The battery life is pretty rough, nothing a 10ft power cable couldn't resolve to still make it very mobile. Not sure why it is up against the steam deck other than the fact it is the only competitor even if it is apples and oranges in terms of performance.
Honestly after the first updates I found it to be useless or not updating drivers to latest version they should be and such. It is present on my computer and that is it. A useless program.
The 3dfx was such an amazing part in gaming. Yes I loved going to my Geforce256, voodoo 2000 and 3000 def holds a special place in my PC gaming heart! Woooooooo
Max bandwidth and what is actually used at the time are 2 very different things. Even if you're using PCI lanes it does not mean you're using them to max potential. 3x NVME + 4090 will still have a very solid performing system.
Enjoy the computer and worry less about performance.
What happens when you turn off xmp in the bios then install in the slots you are wanting? I have to agree with second poster that A2/B2 is how it should be per manual. I have found trying to disable xmp helps with memory diagnostics.