I have Pi 5 and I wish I bought N100. It's unstable, loses internet connection after few days and I have to manually power cycle it. NVMe is patchy, I had to buy a few modules until I found one that is working, but I don't trust it.
Seems like RPi 5 was rushed to stay relevant, but it wasn't thought through.
There are lots of problems with the Pi 5 (the absurd power draw, the lack of eMMC, breaking 10 years of GPIO compatibility), but the PCIe connector is definitely not one of them. In fact it's probably the best thing about it by far because it sets up a new standard, and soon every random SBC will have the same PCIe out port so they can run all of these compatible boards. Some might even support more than one lane eventually.
Also found this geerling review [0] today (which mentions yours as well) which does list slightly higher numbers but he notes that he used actual thermal paste to get better cooling with that gaping heatsink box, which seems to have helped on at least a few fronts. If your cooling theory about the G2 holds, then the memory might be overheating on the X4.
I suspect this is just a matter of timing tweaks in the BIOS.
That aside, it does have some impressive specs (twin ufl ports for external wifi antennas are dope), even though the LPDDR5 is bottlenecked by a dumb 32 bit bus. I was looking to buy one the other day but it's currently out of stock everywhere and the 12/16 GB versions that would be most interesting are nowhere to be seen, so for now it's not really something anyone can buy.
My last Pi is 4 and Pi5 is just completely pointless to me.
edit: as mentioned below, make sure the machine you buy has a socketed WiFi module.
I agree that the RPi5 doesn't make much sense. NVMe needs to be built in at a minimum, and the specialized PSU requirement is a PITA.
Instead, I should wait a few months (or most of a year), triple my budget, and make room for a larger system.
Obviously if $200 is tripling your budget then you're leaving some unneeded peripheral out. The N100 probably won't work either as the cheapest one on Amazon is apparently $120.
N100 boxes are available for purchase today (not just sometime in the mysterious future) for less than $100, delivered.
$300 ÷ $100 = 3, hence: Tripling the budget.
(I could have picked the high end of the range, just as you selected the low end, but that would have been disingenuous of me. $300 is right in the middle.)
Here's an i7-11390H/16GB/512GB system you can buy today on Amazon from a somewhat reputable Chinese brand for $170. Its CPU is ~50% faster than a N100 single-threaded and ~80% faster multi-threaded:
https://www.amazon.com/ACEMAGIC-11390H-Computer-Desktop-Supp...
A similarly priced system with a much faster CPU will be on sale in 3 months, maybe sooner. Feel free to spec a similar N100 system on Amazon (or Newegg or a similarly reputable vendor with no-questions-asked returns) for much less.
I don't need to spend the extra money. I don't need to wait between 3 and 11 months.
I do need a computer today. And if an N100 meets my needs today, then I'm buying one -- today.
Srsly.