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SD Card - SLOW

BigAl07

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Just now flying the DJI FPV system and all of my "current" SD cards give the error "SD Card Slow".

What speed/specification do I need to be looking for now?
 
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Just now flying the DJI FPV system and all of my "current" SD cards give the error "SD Card Slow".

What speed/specification do I need to be looking for now?
I always use SanDisk Extreme Pro cards (90Mbps). I always get the 128GB cards because they aren't that much more expensive than the 64's. But be careful, as there are a lot of counterfeiters out there. I have a couple counterfeit SanDisks in my possession. The thing is, they work, but they come up WAY short performance-wise. I assume the counterfeiters are hoping that people are buying these for their phones or other low I/O devices. In those slower devices, the counterfeit cards do work.

I generally get them on eBay, but I always email the seller to be sure of the card's origin and they have to have 100% feedback. I have purchased them on Amazon, as well.

D
 
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I always use SanDisk Extreme Pro cards (90Mbps). I always get the 128GB cards because they aren't that much more expensive than the 64's. But be careful, as there are a lot of counterfeiters out there. I have a couple counterfeit SanDisks in my possession. The thing is, they work, but they come up WAY short performance-wise. I assume the counterfeiters are hoping that people are buying these for their phones or other low I/O devices. In those slower devices, the counterfeit cards do work.

I generally get them on eBay, but I always email the seller to be sure of the card's origin and they have to have 100% feedback. I have purchased them on Amazon, as well.

D
All good, but a small tip to save a bit of money.
The higher speed listed rating of Extreme Pro & Plus are for photos and high-speed burst shots that a drone will never encounter; it's not helping video capture. The 3 cards have exact same ratings & performance for video, with rating of V30... to improve video would be V60 or V90.

One short article, not the one I was looking for but essentially states the same info:

 
All good, but a small tip to save a bit of money.
The higher speed listed rating of Extreme Pro & Plus are for photos and high-speed burst shots that a drone will never encounter; it's not helping video capture. The 3 cards have exact same ratings & performance for video, with rating of V30... to improve video would be V60 or V90.

One short article, not the one I was looking for but essentially states the same info:

Worth noting, the faster cards move files faster. And if you ever fill that 128GB card with photos or video, you will be glad you paid for the extra I/O.

D
 
Worth noting, the faster cards move files faster. And if you ever fill that 128GB card with photos or video, you will be glad you paid for the extra I/O.

D
No argument on size of card... performance of card on extraction I'd question. The cards higher rating is short bursts only, not constant... my tests indicate near identical for these 3 cards. The main speed improvement is interface to computer... a USB3 is very slow compared to USB3.1. Place card in a newer USB 3.1 Reader, a 3.1 cable (marked 10GB) and a USB 3.1-2 port or Thunderbolt 2 or above port... all about the same extraction speed.

Check the link out...they are all U3 Class 10, Min Speed 30. The Max is only burst... means nothing really.

Edit... my bad, I was focused on Write speed... all 30.
Read speed has a small variation from 95 to 90... on 128GB that amounts to a few minutes. Again, interface hardware will effect it more overall.
 
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Worth noting, the faster cards move files faster. And if you ever fill that 128GB card with photos or video, you will be glad you paid for the extra I/O.

D
^^This!!! The price difference for a UHS-II card is trivial in light of the cost of the platform (the drone). When transferring 100GB at 250MB/s vs. 40 is worth $30 to me.

I just don't get spending thousands on a camera or drone, then getting all chintzy over 30 bucks when it comes to the storage card.
 
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^^This!!! The price difference for a UHS-II card is trivial in light of the cost of the platform (the drone). When transferring 100GB at 250MB/s vs. 40 is worth $30 to me.

I just don't get spending thousands on a camera or drone, then getting all chintzy over 30 bucks when it comes to the storage card.
Wow, Really? Chintzy? That really would be worth it... 250 vs 40... but it's not.. It's a maybe... a possible 95 vs 90 maximum. You're comparing Burst vs Sustained rates... neither is a 40, the "Max" ratings for Pro is 95 and Extreme is 90 on sustained Read, and both cards Write at the same 30 sustained, thus the V30 Rating. Performance in the Craft on flight is zero difference, and swapping cards with battery to extract data while new card installed and sent off on mission... functional & no loss in performance of mission.

On a 64GB Card: Pro vs Extreme amounts to less than 2 minutes if near full. Although I'd agree, with some of the provided links it's clear price differences have narrowed... making price not a big factor anymore per card.

Incidentally, Price isn't always the main factor, more often interface devices are just slow. I use Inspire 2 CineSSD 480GB cards at $1000+ each so you're correct a few bucks isn't a big deal. But the transfer speed of the UG1 or UG2 Card reader with USB3 interface is SLOW... upgrading to the DJI TG3 Thunderbolt Reader cut the time in half and still slower than the CineSSD internal NVMe Card could perform on extraction.

Touching on the practical... transfer rates.
How old is your system and associated devices? Are you running NVMe SSD, Ports are USB 3.1 (or 3.1 v2) and/or Thunderbolt 2-4? Is the internal Drive an NVMe SSD and is your Card Reader a recently newer USB 3.1 device, and using 10gb rated USB3+ cables? Using a simple USB SD - MicroSD Card Adapter (Free adapter that comes with MicroSD card) isn't productive, these are not USB 3.1.

IF NOT up on current hardware, you're not coming close to "possible" advertised speeds of any Card... lucky if 30 to 50 MB/s. Even the Manufacture indicates similar, posted speeds are totally depending on the full hardware path and many systems for the majority of Users don't come close to meeting hardware specs to obtain advertised speeds. I tested 3 high quality Port / Card Readers: USB 3.0, USB 3.1 and USB 3.1v2 using same Cards in each test: Pro vs Extreme... all performed way below advertised speeds with the USB3 reader... overall poor sub 50MB/s. On the USB3.1 & USB3.1v2, they both performed much better and the Pro performed better than Extreme.

Quick Test:
Data Material: 5GB Folder of multiple Images & Video Clips.
To benchmark: Older 2015 MacBook Pro with Thunderbolt 2 (10GB Rated) connected to an Interface with USB3.1 Ports. Full Hardware Interface exceeds capacity of any MicroSD Card: used 2 External Samsung T7 2TB NMVe SSD Drives connected to USB3.1 ports. The 2TB NVMe transferring to 2TB NVMe on 3.1 ports will transfer at 180-210MB/s, indicates the Interface is clearly above the SD Cards Transfer Max rating. Using the same USB 3.1 Port and USB 3.1v2 Reader the MicroSD Cards: Extreme 70-76MB/s and the Pro 79-85MB/s. So minimal gain... few minutes for 64GB card. Soon to receive my new MacBook Pro M1 Max 64GB, 2TB NVMe SSD, TB4 / USB3.2... I'll retest and I'm betting not much difference in Port Transfer... will be limited by 3.1 Reader.

Card Size is always a discussion...
Using a 64 vs 128... on the file size of Mavic or FPV series (less M3 Prores on board NVMe SSD), no advantage of 128 over 2x 64GB... in my opinion, 2 disadvantages: 1) single card failure, 2) larger capacity increases probability of bit failure effecting the card. On a Mavic or FPV, You won't fill the card on 2 Batteries and if applying safe practice is to change on each mission (single flight or multiple if battery change) then no need for a 128gb. I'd rather run 16-24x 64GB cards that I can cycle. Just a personal practice many perform for insurance & security of the material. Just not my practice to depend / use 1 card. So take the price difference Times 16 to 24 cards and it's essentially a minimal gain in performance & bigger difference is cost... your figure at my practice: 16 x $30 would be $480 difference.

Comes down to personal opinion... not really performance... few minutes difference in extraction while craft is off to next mission isn't a concern. If price is near identical in sales, then Pro over Extreme. Size dependent on platform & media saved... for me 64GB work great in smaller platforms.
 
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