SN750 vs SN850 for 27" 2019 iMac?

To those who’ve actually installed a WD NVME SSD in a 27" 2019 iMac:

I’ve read of successful installs with both the SN750 and SN850. What’s your experience been?

[Note: I know an adapter is needed, and a 3 mm heatsink is also recommended.]

And, when installed in a 2019 iMac, is there a performance difference between them? The iMac is 4 x PCIe 3.0, and the SN750 is also PCIe 3.0; the SN850 is PCIe 4.0. Normally one would think there would be no benefit to installing a PCIe 4.0 SSD into a PCIe 3.0 bus, but it’s my understanding that what limits SSD speeds with PCIe 3.0 isn’t the bus, but rather the SSD’s themselves – they’re far from saturating PCIe 3.0 connection speeds. This at least suggests that a PCIe 4.0 SSD would give better performance even if with PCIe 3.0 bus. But I don’t know what is actually the case.

Also: The iMac only has space for a 3 mm thick heatsink. How thick is the SN850’s built-in heatsink? Based on pictures, it seems quite a bit thicker.

Anyways, that’s what I know. Would like to hear from folks with actual experience doing this upgrade.

Hi @byte99,

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance:

OK, I opened one. Let’s see what they say.