This topic has come up quite a lot recently.
I rebuilt my PC in January.
@Franze has rebuilt recently, so has @Kinger and @AndyE will be as well. My system was two Intel generations behind yours so my upgrade was more dramatic. These guys can give more experience to a smaller leap in generations.
So to here are some recommendations - note I will only speak to Intel / Nvidia as those are the product lines I know. You can do the equivalent AMD / Radeon as well. This is also based on the full rebuild concept.
The I7-9700k is very good value especially on sale. Would fully recommend it. Single core performance is what matters at the moment, and this is only beat by hair by the I9-9900k. However, if you don’t do heavy video editing, streaming or rendering the extra expense for the I9-9900k isn’t justifiable compared to a I7-9700k on sale.
Ensure this is well covered by a large Noctua Air cooler or All-In-One water cooler like Corsair’s H-Series (240mm or larger radiator preferably). I prefer water coolers, personally.
DCS will push total system RAM usage well past 16GB with graphics turned up. 32GB of RAM would be my recommendation. 64GB is doable, but not necessary and likely a waste of money at this time for most people. 16GB is not enough for these sims anymore if you want top tier performance. This is critical to avoid pagefile use, which is a way of using diskspace as extra RAM. Storage below will explain why.
For VR you are likely to push up to a 2080ti but these are extremely expensive. Currently a 2070 is exceptional value. I will have to leave VR considerations to more experienced persons, as I haven’t taken the plunge.
This is currently one of the biggest concerns, or it should be. Storage is the slowest part of the system once again - your weak link.
PCI Express based NVMe SSD’s are 2-3x faster than standard 2.5” SSDs. I highly recommend two in your system. One for C drive Windows etc, the other for your sims. The boot and loading times will be stellar, and in DCS you won’t suffer pauses and stutters while the game tries to load from storage.
Don’t try to run DCS from a hard drive, it’s slow and not worth the hassle. Clicking on screen with a HDD can make DCS go “non-responsive” in Windows (if you wait it will typically still load and not crash) but still, this isn’t a recipe for success.
The Operating System:
A full copy of Windows 10 Professional.
In the past MS has botched some updates that corrupted the OS. Windows 10 Pro allows you to delay updates. Home edition does not. This is optional based on your trust of MS, as to if you delay updates or not.
The current Windows 10 version 1909 also added some new CPU load balancing which had made a big difference to older hardware being able to multi-task well. I recommend updating to this current version.
If you would like to just upgrade:
-GPU like @Poneybirds said.
-Get everything on SSD, except you “data” (photos movies documents etc) those can stay on a big HDD. NVMe if your motherboard allows it.
-32GB of RAM would be nice but since Gen4 Intel was DDR3 RAM, I wouldn’t spend the money as you cannot up-cycle it. Upgraded drives and GPU could be taken to the next build, but RAM is now DDR4 series which isn’t compatible.
As for budget:
I cannot speak to USD as a Canadian, but in terms of CAD and pricing up here 2-3k is realistic for a full rebuild with some future proofing. 4K if you like to push things.