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Author Topic: SD 7.0 and SD Express - New SD Card Spec and Interface  (Read 8311 times)

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Offline morst

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #1 on: February 22, 2019, 03:25:51 AM »
whoa.


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Offline jerryfreak

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #2 on: March 29, 2019, 03:53:40 PM »
128TB in your butt

what weve all been waiting for!
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Offline morst

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #3 on: March 29, 2019, 03:59:13 PM »
128TB in your butt

what weve all been waiting for!
thanks, but I will wait until it fits in my nostril. (MicroSD and yeah, I've checked)
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Offline jerryfreak

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #4 on: July 20, 2019, 04:53:44 PM »
none of the devices we use actually have the pins for UHS-II, right? im pretty sure at this point thats only a camera thing

i technically havent even seen a recorder that lists UHS-I as a spec, usually they just say sdhc or sdxc

i usually dont spend a ton of money on cards, just mid grade ones that work, here are some ive tested with the h2testw windows software, sequential read and write across full card. Ive seen older class 4,6, and 10 cards test slower but none really much faster than these. this is with the PCI card reader on my five-year old laptop, i will try to procure a modern usb3 reader and see if any can go higher. technically they should test a bit higher per the tests on this site:

https://havecamerawilltravel.com/photographer/fastest-sd-cards
https://havecamerawilltravel.com/photographer/fastest-microsd-cards

sandisk extreme pro 32gb microsdhc (U3/UHS-I/V30)
https://www.amazon.com/gp/product/B06XYHN68L
Writing speed: 46.9 MByte/s
Reading speed: 64.9 MByte/s

samsung evo select 32 microsdhc (class 10/U1)
https://www.amazon.com/gp/product/B06XWN9Q99
Writing speed: 23.4 MByte/s
Reading speed: 61.4 MByte/s

lexar 512GB microsdxc (U3/UHS-I/V30)
https://www.amazon.com/gp/product/B07KBQQ82D
Writing speed: 42.7 MByte/s
Reading speed: 63.7 MByte/s

sandisk 128GB ExtremePlus SDXC (U3/UHS-I/V30)
https://www.bestbuy.com/site/sandisk-extreme-plus-128gb-sdxc-uhs-i-memory-card/6299412.p?skuId=6299412
Writing speed: 41.1 MByte/s
Reading speed: 65.8 MByte/s

technically ANY of these should be fast enough for our purposes. even a mixpre6 writing (8) 24-192 channels is only writing at 4.5 MB/sec

however that doesnt mean that all cards are equal. the 512GB lexar microsdxc above will stutter and skip on my PCM-A10 when playing 24-96 FLACs (which requires under 0.5 MB/sec). I have not been able to reproduce that with the 32GB sandisk pro SDGC, or the internal memory. even though the lexar card should be plenty fast enough, id be leery to record direct to it (esp as 24/96 wavs are a higher write speed than 24/96 FLACs due to lack of compression)





« Last Edit: July 20, 2019, 06:56:38 PM by jerryfreak »
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Offline voltronic

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #5 on: July 20, 2019, 09:16:15 PM »
I would not put too much stock in those speed ratings.  They matter, but not quite as much as you might think.  Remember that the class and speed ratings are based on burst read / writes as you see in video / photo cameras and other typical file transfer applications.  Audio recording doesn't necessarily work that way.  From what I understand (there is very little out there on this topic), audio recorders write to the media in a sustained stream, more or less.  That's not something SD card manufacturers measure or publish, which is why you see audio recorder manufacturers having to test cards themselves.  In other words, it's not enough to trust the numbers on the card package.  You see some very high-speed rated cards failing to work in these devices, because the manufacturers aren't testing them in this way.  For instance, I have a very old Transcend 16G card that is quite "slow" by today's flash media standards, but handles 4 channels of 24/96 with zero hiccups.

Standalone audio recorders should have a memory buffer before writing to the flash media, but if that buffer memory is small and/or the card can't keep up, you run the risk of buffer underrun errors which cause dropouts in your recording.  This was the central theme of the drama with the Tascam DR-70D and it being "picky" about SD cards.  The theory a few of us had was that this particular recorder has a small memory buffer, which would make the sustained-write performance of the SD card even more important that usual.  There were members that complained that their very expensive new cards were failing (while my old & cheap Transcend ran like a clock) and even after what I laid out above was explained by the company rep, they were convinced that the speed rating on the card packaging was the be-all-end-all of how it would perform in an audio application.  Clearly, we know that isn't the case.
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Offline jerryfreak

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #6 on: July 21, 2019, 06:23:16 AM »
correct, which is why im only concerned about sustained sequential write speeds in both the tests i did and the website i cited.. its all that is relevant for our application
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Offline voltronic

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #7 on: July 21, 2019, 08:13:31 AM »
correct, which is why im only concerned about sustained sequential write speeds in both the tests i did and the website i cited.. its all that is relevant for our application

Ah, I somehow missed the word "sequential" in your post.
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Offline jerryfreak

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #8 on: July 21, 2019, 01:48:29 PM »
My Mixpre 6 is giving me ‘sd card is slow’ error and stopping recording of eight 24/192 channels on several of the cards above so clearly there are other factors, unless my recorder is defective. Still researching the best way to qualify cards. Even though I will prob never record 8 tracks at that high bitrate it’s the best I can do for a ‘torture test’ on the device itself
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Offline jerryfreak

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #9 on: July 21, 2019, 03:13:04 PM »
Remember that the class and speed ratings are based on burst read / writes as you see in video / photo cameras and other typical file transfer applications. 

actually many of the ratings such as class 4,6,10, U1, U3, V30. V60, V90 are actually based on sequential write speed, though im still puzzled how 4.5MB/sec fails to write to a card that is rated at 30 MB/sec and tests over 40 MB/sec.... at some point i have to blame the device implementation

One thing i came across yesterday, though i cant remember where, is a statement that cards are faster when empty because they somehow use free space for caching. I started testing that 128GB sandisk in the mixpre with the aforementioned 4.5MB/sec write, it was flawless until the card hit 60-70% full after 4.5 hours of testing. The Anker USB battery i was using dropped from 3 to 2 lights around the exact same time (out of 4), so im wondering if its kicking out less power and making the mixpre perform not as well. still investigating

even fresh (quick) formatting didnt fix the card's slow speed issues, i tried a slow low level format in my computer and will then do a format in the device itself before resuming testing
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Offline voltronic

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Re: SD 7.0 and SD Express - New SD Card Spec and Interface
« Reply #10 on: July 22, 2019, 11:12:39 AM »
I never knew those class ratings were based on sequential writes.

It's possible there could be some weirdness going on with your MixPre, but there seems to be hard to tell if a certain card will or will not work in these kinds of recorders anymore, no matter how they test using "normal" means as you have done.

I have heard the same thing about failures increasing as the card fills up, but no explanation as to what would cause it.  If we take the buffer underrun theory and run with it, you could imagine a scenario where every time you hit a "slow" sector on the SD card, it dips into the buffer as it should to account for that.  Over a long time and after an accumulation of more times where that occurs, you could be "living on the edge" of the write buffer bottoming out.  So, it may not be that the "end" of the card is worse than the "beginning", but a function of the implementation, as you suggest.
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Acoustic Recording Techniques
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