Buying advice for nvme m.2 SSD and GPU on the Asus X99-aii

[lydian_b7]

Hi all,

I have a system based upon KGP's x99 imac pro from old days...
Asus x99-aii
i7 6950x
Corsair H80i v2
Trident Z's (4x8GB ddr4 3000 mhz)
Samsung 960 evo 1 TB
GC Alpine Ridge Thunderbolt ad-on card
EVGA SSC GTX 1050 ti
EVGA 850 GQ (850w gold power)
UAD Apollo 8 duo (with apple TB3-->TB2 adapter) and Quad Satellite (plugged in apollo itself)

It served me very well through the years but it is stucked with High Sierra 10.13.6
I am using this machine for Audio Productions (Pro Tools / Ableton Live / Logic Pro)
I need to update macOS at least Big Sur and preferably Monterey for these days.

Ever since I saw this CaseySJ thread and another user's successful 12.2 monterey installation with very similar build as mine I wanted to give it a try only with grabbing a Sapphire RX580 from 2nd hand market (very good price) and grab a supported WD NVME before going for a full compenents upgrade.

My question is about WD SN850 or WD SN850x which will be PCIe 4.0 on a PCIe 3.0 based mobo Asus x99-a ii.
I want this SSD upgrade futureproof compatibility for newer gen mobos with PCIe 4.0 in case of going newer hardware in the near future so I wanted to go for WD SN850's.

What do you think guys about using WD SN850 PCIe 4.0 m.2 ssd on a PCIe 3.0 m.2 slot based mobo ? (sorry for the nooby question)

Also I can find good deals for Sapphire Pulse 6600xt instead of rx580 on 2nd hand market locally but in case of going backwards from Monterey to Big Sur (due to incompatibility of some old software, plugins and Virtual Instruments with monterey) RX 6600 xt would work on Big Sur ??

Thanks in advance.

 

[etorix]

PCIe is backwards compatible. There's no issue using a PCIe 4.0 device in a 3.0 slot.
RX 6600 (XT) requires Monterey 12.1 or later.

 

[lydian_b7]

PCIe is backwards compatible. There's no issue using a PCIe 4.0 device in a 3.0 slot.

Thanks that's what I want to hear.

Btw;
sorry to bother the forum opening a thread in a hurry about easy pezy question such above.
After posting this, I realized that I could ask under Build Recommendations for older versions of OS X/macOS using older Chipsets topic as a message. Apologizes to moderators, please be free to delete this thread, If you see it necessary.