# UHS-I or UHS-II with 90D?



## AlanF (Sep 17, 2019)

As a stills shooter, will I miss out by not using a UHS-II card for the 90D? Downloading to the computer will not be speeded up for me as the camera has only a USB 2.0 connector and I don't want to use a fast external card reader, and I doubt if I'll be downloading more than 32 GB at any one time anyway. Will the slower write speed of a Sandisk Extreme Pro, for example, slow down the bursts?


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## koenkooi (Sep 18, 2019)

From the early hands-on reviews it sounds like the 90D has a bigger buffer than the M6II, so you're less bound by card speed in bursts. The big caveat with UHS-I and UHS-II is that using a type II card in a type I slot tends to have lower performance than a type I card in a type I slot.
Your use case shouldn't have any weird slowdowns due to type I card in type II slot, that's perfectly fine.

In my RP the difference between I and II were obvious, with a fast UHS-II card it keeps shooting at max fps (which isn't a lot), with a UHS-I card it would slow down after a few seconds when the buffer filled up.

I personally went with UHS-II cards for all my cameras since I use a fast external reader which made downloading more than twice as fast compared to UHS-I cards. In your case, how often have you outrun the buffer in the 90D in the past few days?


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## bhf3737 (Sep 18, 2019)

The site Camera Memory Speed has result of speed test for several UHS-I and II cards for many cameras. Of course 90D is not there yet. Apparently the average write speed differs depend on the implementation by manufacturers. Canon's UHS-II implementation tops around 180MB/S and about 75 MB/S for UHS-I cards. In the tested card list, there are several Sandisk Extreme Pro cards with various speed ratings. Given the SD cards getting cheaper and cheaper, for me, using UHS-II cards with twice write speed compared to UHS-I seems to be a good decision.


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## AlanF (Sep 18, 2019)

Thanks for your input. The price difference on Amazon UK for Sandisk Extreme Pro UHS-1 and -II cards is a factor of 4. Eg 64Gb 170MB/s is £24, and 300MB/s is £100. (I have a couple of virtually unused Extreme Pros in the 2nd slots in my 5DIV and 5DSR .) So, it's whether it will make a difference.


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## koenkooi (Sep 18, 2019)

Someone on the DPReview forum tested a bunch of cards in his R: thread. It's long and dry, but worth a read.


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## AlanF (Oct 27, 2019)

I bought a 32GB Sandisk 2000x 300/s UHS-II Extreme Pro (cost £52) and compared it with my new 64GB Sandisk 170/s UHS-I Extreme Pro (cost £22) on my 90D. Under the same conditions, I let it go for the full burst and then another 5 shots. With the UHS-I the burst was 22 full RAW and then about a shot every 0.5s, and then 15s to write fully to disk. For the UHS-II, it was basically the same a burst of 23 shots, then a similar speed of 5 shots in about 2s , and 15s again to write full to disk. If I try continuous shooting, there is the burst of 22 shots, 7-8 slow ones in about 3s, then a series of short bursts with pauses in between. Importantly, the camera keeps working with these short bursts while the writing to disk continues and doesn't seize up - as space in the memory becomes available, the camera will fire.

Do I think the the UHS-II is worth the extra cost? Not for the way I use the camera, but others might think so.


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## AlanF (Oct 29, 2019)

I checked that the SanDisk Extreme Pro UHS-II does write files at >230 Mb/s and the UHS-I at >85 Mb/s. So, the 90D appears to be throttling the writing to the card to an estimated 60Mb/s.
I found a thread - https://www.dpreview.com/forums/thread/4432716?page=3 where it seems there isn't much advantage in using a fast UHS-II card with the 90D or M6 II.

I followed the recommended procedure in the dpr thread https://www.dpreview.com/forums/post/63202460 to measure the write speed.
Low format card, set to 1000/s iso 100 in Manual with body cap on. Shoot RAW files for 1 minute and time the complete writing to card. DLO, peripheral illumination etc etc etc were all turned off.

1. 64Gb SandDisk Extreme Pro UHS-I gave 246 19.8Mb files, 10 s clearance, 4.87Gb = 70 Mb/s
2. 32Gb SandDisk Extreme Pro UHS-II gave 259 19.7Mb files, 10 s clearance, 5.10Gb = 73Mb/s

So pretty much a waste of time getting the UHS-II cards for stills shooting. If you take them out of the camera and use a UHS-II card reader to download to your computer, it will save a few seconds.


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## Keith_Reeder (Nov 14, 2019)

I had the same dilemma with the M6 Mk II, Alan - I decided on a 128gb "fast" UHS-1 card, because I never max out on a burst, and the UHS-1 card is _plenty_ fast for how I actually shoot.

_Much_, cheaper, of course - and I really appreciate the capacity.






128GB Kingston Canvas React Micro SDXC UHS-1


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## Mt Spokane Photography (Nov 14, 2019)

I purchase UHS II cards for my EOS R, its the future, so I spend a few dollars more and get them. I have two now, a Lexar 128 GB 1000X UHS II is currently in my camera. It cost me $50 last Christmas, they will probably cost less this holiday season. Its not the fastest card, but it is more than what I need.


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## Keith_Reeder (Nov 14, 2019)

Unfortunately, the price difference between UHS-I and UHS-II in the UK is _really_ off-putting - right into "if you don't _need_ it, don't do it..." territory.

Hmmm... Having said that:






Lexar Professional SDXC Card UHS-II 150MB/s 4K 64GB


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OK, just ordered it.


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## AlanF (Nov 14, 2019)

Keith_Reeder said:


> Unfortunately, the price difference between UHS-I and UHS-II in the UK is _really_ off-putting - right into "if you don't _need_ it, don't do it..." territory.
> 
> Hmmm... Having said that:
> 
> ...


The Lexar 1000x UHS-II reads and writes slower than the SanDisk extreme pro 170mb/s.


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## Keith_Reeder (Nov 14, 2019)

Ah well - it'll do as a spare, if nothing else...


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## Michael Clark (Dec 11, 2019)

The thing to pay attention to with using UHS II cards in UHS I devices is how the controller in the card is set to deal with UHS I connections. Some default to the maximum UHS I speed (SDR104 mode - 104 MB/s), but others default to the slower base UHS I speed (50 MB/s). So it can vary from one UHS II card to the next when used in a camera with UHS I card slot.

From Camera Memory Speed's page for the EOS 5D Mark IV:

"It should be mentioned that the older SanDisk Extreme Pro UHS-II 32GB SD card did not perform as well as other UHS-II cards because that particular card does not support SDR104 UHS-I bus mode and operates at lower 50MB/s bus speed, whereas the newer Extreme Pro UHS-II microSDXC 64GB card does support the faster SDR104 bus mode."


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