I’ve been reading articles online about a supposed speed advantage for the Resilient File System, aka ReFS, in Windows. But I’m observing some caveats when it comes to exploiting ReFS speed advantage. Let me use a speed check from the Lenovo ThinkStation P3 Ultra as an example, mounted in a USB 3.1 Gen 2 (10 Gbps) NVMe enclosure. Quick examination makes the point nicely: one sees no difference vis-a-vis NTFS. Indeed the speeds shown are entirely typical of any UASP devices at nominal 10 Gbps speeds.

Exploiting ReFS Speed Advantage Requires 20 Gbps or Higher

Do the math: 982.75 MBps = 7,862 Mbps = 7.67 Gbps. That’s about as fast as a USB 3.1 Gen 2 (10 Gbps) device can go in a real-world situation, such as running the CrystalDiskMark benchmark. My basic point, therefore, is this: Don’t switch to ReFS for performance gains unless you have a device that can deliver 20 Gbps (or higher) performance. That means USB 3.2 Gen2 (20 Gbps) or USB 4/Thunderbolt 3 or 4 (40 Gbps).

So I tried the same enclosure, same SSD, same cable (all of these factors count) with both ReFS and NTFS. I found it easiest to use the “Create a Dev Drive” option in the Dev Home app to start the former. Disk Mgmt worked find for the latter. Here are those results, which do show ReFS has a speed advantage — but it’s pretty small.

If you compare the big block write speeds (upper 2 left cells) that’s where the advantage is noticeable. For the rest of the cells, it’s barely there.

True, But Nugatory

I’m going to have to mess around with faster SSDs and see if that helps. But so far, I don’t see the uptick as big enough to be worth a lot. That said, as 24H2 goes final I should try again. The P3 Ultra isn’t getting that update offer yet, and that’s usually for good reason. If this changes, I’ll update this post accordingly. Right now, it’s mostly a ho-hum level of added performance.

OK, so I tried it on a different PC — a ThinkPad P16 Gen 1 Mobile Workstation — running 24H2 preview version. It shows modest improvements over the P3 Ultra but nothing spectacular. I’ll keep checking and reporting back here. It’s possible there’s more to see than I can tell just yet. I’m going to run a Macrium Reflect Backup next…