I've used both SATA + NVME SSD
The difference between both is negligible as not a lot of apps / games can utilize NVME

Windows 10 Cold Boot Time (Fast Boot Enabled)
Single HyperX SAVAGE 240GB : 9 seconds
Dual HyperX SAVAGE 240GB RAID 0 : 15 seconds
Samsung 950 PRO 512GB : 3 seconds (I kid you not)

But it all comes down to your pocket
If you can afford NVME, go for it
If you think an NVME SSD is too expensive, then go for SATA SSD

For 950 Pro, yes

When booting Windows, the motherboard have to load the RAID driver & instructions first
But once you're in Windows, everything will be faster than a single SAVAGE

Speaking from my personal opinion & experience using many types of SSD, boot time doesn't really matter, what matters most the loading time for applications & games once you're inside of Windows

But with NVME SSD's, you can have both

Guys, just let him decide lar

As I've said earlier, it all depends on your wallet, if your wallet is thick enough, go for NVME
If not, just go for normal SSD will do

Some people think RM1500 for a 512GB SSD is too expensive
Some people think it's just a small amount for a decent upgrade

I on the other hand got the 950 Pro for free so it really doesn't matter LOL

For that budget, I'd suggest you to go with AIO liquid cooling
AIO liquid cooling provides much more benefits over huge-ass air cooling

With AIO liquid cooling, you will get these:
1. Bigger headroom for you to work around the CPU
2. No "motherboard bending" issue
3. Less dust in the casing
4. Depending on the model that you're buying, stable idle & load temperatures
5. No worries about the heatsink breaking the motherboard when you move the computer around