Copying 3 SD cards to FW800 - Bottleneck?

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I have a late 2011 MBP 13" that I will be off-loading 3 SD cards at a time to a FW800 drive enclosure. 2 cards will be connected over the USB 2.0 ports and one card will be in the card slot.

My question is this - where will the bottleneck in bandwidth be? Will it be advantageous at all to have a SSD in the FW800 drive enclosure, or will a mechanical drive do just as well if there is a bottleneck in the USB connection?
 
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USB2 runs at 480MB/s so that is where the bottleneck will be. Even an SSD will be throttled by USB2. Sounds like a job for patience.
 
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USB2 runs at 480MB/s so that is where the bottleneck will be. Even an SSD will be throttled by USB2. Sounds like a job for patience.

So will all three SD cards be running on the same 480MB/s of bandwidth despite 2 of them being on separate physical USB connections at the side of the MBP and one being in the SD card slot?
 

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Your primary bottleneck is likely to be the brand of SD card(s) being used. They are not all created equally. Some are so slow they won't even show that much difference between read/write times whether you're using USB 2 or USB 3.

Your next bottleneck will be the Firewire. Reading is much faster than writing. There is no point in putting a SSD into a FW enclosure.

Thirdly, copying from multiple locations to a single location, you are going to be fragmenting those files big time. The larger the file sizes, the more fragmentation you are going to have. This will slow the read times from that drive. Personally, I just wouldn't do it.

If this is work related, or you intend for this external drive to now be the sole storage point for these files - you need another drive for a backup.
 
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Your primary bottleneck is likely to be the brand of SD card(s) being used. They are not all created equally. Some are so slow they won't even show that much difference between read/write times whether you're using USB 2 or USB 3.

Your next bottleneck will be the Firewire. Reading is much faster than writing. There is no point in putting a SSD into a FW enclosure.

Thirdly, copying from multiple locations to a single location, you are going to be fragmenting those files big time. The larger the file sizes, the more fragmentation you are going to have. This will slow the read times from that drive. Personally, I just wouldn't do it.

If this is work related, or you intend for this external drive to now be the sole storage point for these files - you need another drive for a backup.

Great advice! Thanks for the reply.

All of the cards are Sandisk Extreme at least, if not, Extreme Plus. This is going to be footage copied off and the drive it is going to is shipped out to the client. I'll already have two back ups on my end.

Unfortunately, no USB 3 on the late 2011 MBP's.

I think the best thing to do is do some trial runs with an SSD and a mechanical drive I have sitting idle here at the office and time each one in the same exact scenario I'll have in the field.

It's obviously more cost effective to go with a 1tb mechanical drive over a 1tb SSD if the performance is negligible. But if I can eek out a spare 5-10 minute with each transfer of 3 SD cards at a time, that would highly beneficial.
 

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Yeah, if it's work related, time is money. I use to do a lot of video encoding which is highly CPU intensive - which made it well worth while to buy the absolute best CPU I could afford and overclock it. Even 5 minutes an hour can add up fast if it's something you'll be doing quite often.

While you're testing, you may want to try 2 at a time also. If there is an issue with the writing speed, backing off to 2 vs 3 could see a time savings. Of course you'll need to weigh out how much time you want to spend sitting at the computer &/or if you'll be sitting there during the copy process. Try to load your test SD cards up with similar file sizes that you'll be copying out in the field for best test results to know what to expect for your real world experience later.
 
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Just to report back my findings. I did a straight copy from three cards at once. Two cards were from card readers attached over the USB 2.0 ports, and one card attached via the card slot directly in the Mac.

On the first test, I used a 160gb (fairly certain it is 5400rpm) mechanical drive that originally came in my 17" Macbook Pro 7 years ago installed in a FW800 enclosure.

The second test used the same enclosure, but instead used a Samsung 256gb SSD. The data total from the three cards was 62.5gb of video.

The mechanical drive took 24m:50s to copy over, while the SSD took exactly 19m:00s. This set up is as real world as I can make it, using footage from previous events still available on the cards.

I ordered up a new 1tb 7200rpm mechanical drive and will re-run the test.

Not a bad idea trying 2 cards at a time instead of 3. I'll give that a shot in the future as well to see how it goes. I'll be working on other aspects of the project while the cards are copying down, so getting 3 down at a time would be nice while I'm working on things non-computer related for the project.
 

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