Is a high-speed portable SSD really worthwhile

I won't go into all the background, but I recently bought a Corsair EX400U 2TB which was a fairly priced for what you get - actual Thunderbolt 4/USB4 speeds. I have a lot of data (>3TB) between videos, photos, archives and other data spread out over my Surface Pro 9 Intel (256 GB SSD), a 4 TB, WD MYCloud NAS and my 1 TB Onedrive account. I've been working on cleaning up and re-organizing this to minimize the moving around and maintaining access from my Samsung Galaxy phone, not to mention sharing accounts with family members.

I decided to get the Corsair so I would have high speed access to dealing with large GoPro video files I take for one of my hobbies. While the Corsair is quite faster than the specs of the rest of the network and system, I was expecting to get very fast transfers with my Surface Pro for working on the videos. Turns out that while the Surface Pro supports Thunderbolt 4 on its USB C ports, I ran into another bottleneck. When I got the Corsair, first thing I did was test actaul transfer of a 30 GB video file from the Surface to the Corsair and it took about 60 secs. That was disappointing as it meant transfer rate was about 500 MB/sec - not the expected 3000-4000MB/sec. I then tried transferring the file from the Corsair to the Surface and while the results were about twice as fast, they were still way below the capabilities of the Corsair. I then tested both the Corsair and Surface SSD with CrystalMarkDisk. The Corsair was in the 3000-4000 MB/sec range while the Surface was in the 3500-1500 MB/sec range. These results did not explain the actual transfer speeds I was getting.

I then used my AI Agent to help troubleshoot this. We looked at several issues but none solved the problem. Long story short - we zeroed in on the Surface's SSD cache. The SSD, provided by Samsung to Microsoft, has a cache that is jsut big enough to run benchmarks like CrystalMarkDisk very well since the data transfers never exceed 1 GB by default. But if your file exceeds this, it then falls to a sustained read/write of 450 MB/sec. Which means about 1/10th the speed that Thunderball and my drive can support. Lesson learned.

This doesn't mean I can make use of this speed. I can work on these files directly on the Corsair and this will be very fast. The corsair even comes with a Magsafe backing and a special cable for your phone (Apple/Samsung) so you can capture data directly from the phone. But for data transfers on my system, I will need to come up with some other strategies to improve the speed.