One thing that jumps out at me immediately is the dual GPUs. If the operating system treats them like a single GPU, it might not be an issue, but in general, X-Plane does not recognize (and probably will not for the future) a 2nd GPU so it is not worth spending money on it.
While the X-Plane team is primarily on Macs, it's due to ease of use of programming tools, not for gaming power. In general I find that you can get a lot more GPU and CPU power for the money if you look at Windows computers.