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- #SAMSUNG PORTABLE DVD WRITER MODEL SE 21888 HOW TO#
- #SAMSUNG PORTABLE DVD WRITER MODEL SE 21888 PRO#
#SAMSUNG PORTABLE DVD WRITER MODEL SE 21888 HOW TO#
Well, but cheap SSDs show less performance than these eMMC modules and since we're solely talking about SBC here the question remains how to connect an SSD? If you've an A20 device you're lucky since you can SATA 100 MB data size to get the idea when you're only testing your disk's caches and when your disk in reality. Therefore check random IO results with small record sizes since this is important and have a look at the comparison of 1MB vs. Most fs accesses on an SBC are not large data that will be streamed but small chunks of randomly read/written data. So you save money and get better performance by choosing the cards that look worse by specs! The cheaper EVO/EVO+ with 32 and 64GB show identical sequential transfer speeds while being a lot faster when it's about random IO with small files.
#SAMSUNG PORTABLE DVD WRITER MODEL SE 21888 PRO#
File size has to reach 512K to let USB disk perform as good as the SD card! Please note that I used a Samsung Pro 64GB for this test.
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830 IOPS (13329 KB/s) so SD card is still 7.5 times faster than USB disk. 1950 IOPS (7812 KB/s) so SD card is ~18 times faster, for 16k size it's ~110 IOPS (1716 KB/s) vs.
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So if you compare random reads with 4k and 16k record size and 100MB data size you'll notice that a good SD card will perform magnitudes faster! For small files (4k) it's ~110 IOPS (447 KB/s) vs. Most of the accessed files are rather small especially when you configure your web server to deliver all content already pre-compressed. Imagine you want to set up a lightweight web server dealing with static contents on any SBC that features only USB. It always depends on the use case in question. Sequential read speeds are way higher, random IO will always be superiour and this is more important) When you have both USB and SATA not using the latter is almost all the time simply stupid (even if sequential write performance looks identical. SSDs behave here differently since they do not contain ultra-slow rotating platters but their different types of internal storage (DRAM cache and flash) do not perform that different With HDDs data size matters since you get different results depending on whether the benchmark runs inside the HDD's internal caches or not. Even that slow that they are the bottleneck and invalidate every performance test when you want to test the performance of the host (the SBC in question)