Friday, July 24, 2015

Data Storage: Is Inexpensive Memory Worth It?

The question, "Are inexpensive memory cards/HDD/SSD's worth while?", has been asked millions of times, but I thought I would go over it based on my experience and testing anyway. This is not a deeply scientific test, and I'm not going to start speed rating hundreds of cards to find out which is the absolute fastest. The question I was trying to answer with this test is, how much do I have to spend to get a decently fast SDHC card that won't break the bank? I've thrown in some HDD's and an SSD just for sake of it. All products tested are items I use in my normal workflow and were not given to me.

Devices Tested: (Prices from, on July 23, 2015)

Memory Cards

1x Patriot 16GB LX Series SDHC Class 10 ($11.49 Cdn)
2x Lexar Professional 16GB 400x SDHC UHS-I Class 10 ($26.99 Cdn)
2x Lexar Professional 16GB 633x SDHC UHS-I Class 10 ($16.99 Cdn)
1x ADATA 32GB UHS-I microSDHC Class 10 ($11.50 Cdn)

Computer HDD/SDD

1x Western Digital 1TB Black 3.5in. Internal Hard Drive (under $100 Cdn)
2x Seagate ST2000VN000 2TB 64MB SATA 6GB/S 3.5in NAS Hard Drive ($111 Cdn each)
1 x 64GB SSD 2.5in. External SSD (Cheap drive, brand no longer available)

For this test I pitted a number of SDHC cards, and SSD and some traditional hard drives against one another.

First here is the test setup, all devices were test on a 2011 2.7Ghz Core i5 27" iMac, 16GB of RAM, with a 1TB Western Digital Black 3.5in. internal drive. Memory card tests were not done using the internal SD card reader, since it is limited in terms of speed, being connected to a USB 2.0 bus. Thus tests were completed via a Thunderbolt adapter that provides USB 3.0 and eSATA, with a USB 3.0 card reader. Below is the listed hardware used:

1 x Startech Thunderbolt to eSATA + USB 3.0 Adapter (Max speed 10GB/s over Thunderbolt)
1 x Vantech Super Speed USB 3.0 4 Port Hub (With external power supply)
1 x Sandisk Super Speed USB 3.0 Card Reader (The white one you can find on amazon)
1 x Vantech NexStar MX (USB 3.0 Dual Drive external with RAID support)

Finally the speed testing itself was run using Blackmagic Disk Speed Test on Mac OS 10.10.4. Each device was uploaded a 5GB file, which was then read. I found no noticeable speed differences when sending smaller files (1GB is the smallest this app will deliver).The below image displays the results. Each drive was tested multiple times, and these numbers show the average speeds that Blackmagic Disk Speed Test provided.

SD Memory Cards:

Out of the memory cards tested the real looser was the Patriot 16GB LX Series card which had maximum read speed of 21.6MB/s and a write speed of only 9.9MB/s. This was somewhat expected, since this card has been on the market for a number of years now. The others were all much better with read speeds averaging at 38MB/s. The fastest overall card was the 32GB ADATA which had a write speed of 26MB/s, with the Lexar 400x and 633x lagging behind at 20.5MB/S. While none of these cards are a match for Sandisk Extreme 95MB/s cards, they are also significantly less expensive per gigabyte, so unless you are shooting extreme action or sports they could be a good choice.

One explanation of why the two types of Lexar cards run at the same speed is that many of the 16GB cards write at slower speeds than 32GB cards. There are technical reasons for this, such as the physical size of the memory chips in the card, but I will not be getting into that. The 40MB/s read and 20MB/s write speed for these two card types are what is advertised by Lexar, so the fact that all four cards tested basically achieved that is a good sign that you are getting what you paid for. From this test it becomes clear that the Lexar 16GB 633x cards are simply rebranded 400x cards. The 32GB versions are advertised to work at 633x speeds, and other tests bare this out. Personally I perf to use 16GB cards. Thankfully the 16GB 633x cards are significantly less expensive than the 16GB 400x cards, so there is not any bait and switch going on here.

Computer Drives:

Out of the 2.5" and 3.5" inch drives the clear winner for read speeds was the 64GB SSD (from 2012), with a max read speed of 183MB/s. The write speed wasn't great at 60MB/s, and all the internal and external drives tested were faster at writing. The internal Western Digital Black's (7200rpm) write speed was 88.2MB/s, with read speeds of around 91MB/s. The two Seagate 2TB NAS drives (5900rpm) in an external USB 3.0 RAID 1 setup were a real surprise, with write speeds of 137MB/s and read speeds of 141.7MBs.

Conclusion: Cheap cards don't have to be slow, or bad, just do some research before you click the buy button. Hard drives and SSD's, similar story. Personally I don't cheap out on HDD's because the slower drives tend to have short (1 year) warranties and higher failure rates.