topic Re: Sandisk extreme plus v30 vs Sandisk ultra v1 in Camera Accessories

Sandisk extreme plus v30 vs Sandisk ultra v1

Bfs1 — Mon, 02 Jun 2025 23:30:53 GMT

Upon buying my canon 80d i purchased a Sandisk ultra v1 for video, at the time i didn't know it was coming with used Sandisk extreme plus v30. My question is, is there real big of difference between the two in terms of writing speeds? I've only used samsung evo cards for my osmo action which is also a v30 and was recommended the ultra from someone at best buy.

Re: Sandisk extreme plus v30 vs Sandisk ultra v1

rs-eos — Tue, 03 Jun 2025 01:51:33 GMT

Yes, the U3 card will allow writes up to to 3 times faster than the U1 card. 30 MBps (240 Mbps) vs 10 MBps (80 Mbps). You'd have to check your manual on what type of video you'd be capturing and see if that falls below these sustained write speeds.

Re: Sandisk extreme plus v30 vs Sandisk ultra v1

AtticusLake — Wed, 04 Jun 2025 09:35:51 GMT

Really, neither of these cards is ideal for high-spec video - for that you need a "v" rating, and neither of those cards has that. For example, v30 would be 30 megabytes per second -- that's the same rate as U3, but measured under circumstances that more closely match high-spec video recording, to ensure that the card doesn't ever drop frames.

For the 80D, you're probably fine with the U3 card, maybe even the U1 - I can't find what bitrate it records at, but it's HD only, so it's not too demanding.

Re: Sandisk extreme plus v30 vs Sandisk ultra v1

Waddizzle — Wed, 04 Jun 2025 11:59:29 GMT

Does this chart help?

Re: Sandisk extreme plus v30 vs Sandisk ultra v1

AtticusLake — Sat, 07 Jun 2025 07:39:50 GMT

With a big caveat. The chart shows that C10, U1, and v10 are all equivalent in terms of the nominal speed, but in fact they are not equivalent in terms of real-world flash memory performance - at least not on all devices.

The issue is that because of how flash works, its performance depends critically on how you use it. If you have a basic flash drive, and access it sequentially, you'll see the rated performance; if you access it non-sequentially, performance can drop A LOT. I'm not talking about losing 10% of your performance, I'm talking about losing more like 90%. I hit this on a tablet product I was working on, and I had to develop my own flash memory benchmark to account for it.

The SD card rating standards have developed over the years - early devices only did sequential access, so a fancy testing scheme wasn't needed; but for more complex devices, like modern video cameras, you need to ensure that the flash card delivers the rated performance under more complex usage scenarios. You could be recording video and audio in separate files - like my camera can do - or you might be recording a separate file of meta-data, or gyro data, or depth data, or whatever, in parallel with the video. Or all of the above.

So the three sets of rating standards use different testing criteria. I don't know exactly what they are - this information isn't exactly public - but the "C" standard is very simple, whereas the "v" standard is much more complex - it tests the speed while writing multiple streams of data at once, which more closely matches how some cameras record video. Which in practice means that to pass "v", an SD card needs more RAM buffers internally, a more sophisticated controller, stuff like that.

So for video, or certainly for high-standard video (4k, 10-bit, etc), you really need a card with a "v" rating.

I explain all this in a video I made: https://moonblink.info/MudLake/tech#Cards