What's the fastest USB 2.0 flash drive or SDHC card?

sofakng

Senior member
Jul 19, 2004
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My car stereo (Parrot SMART Asteroid) can read MP3s off a USB 2.0 drive or SDHC card.

Which is faster?

I believe that USB 2.0 maxes out at 30 MB/s and I think SDHC is around the same time, right?

What about random access? (since they are both flash memory, which is the fastest [?], it should nearly SSD speed, right?)

My goal is to find the fastest method of storage because my car stereo also indexes all music from the drive so anytime I update the stick it needs to re-index, so I'm looking for the fastest available method...
 

ALIVE

Golden Member
May 21, 2012
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you can not go faster than this
usb flash drive will be limited always to the usb2 bus giving you max 25mb of transfer. sdhc or sdxc card will not have this limits

so 90mb transfer rate is fast enough for you?
 

tcsenter

Lifer
Sep 7, 2001
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It depends on the SDHC controller as well as the card. The above-linked Sandisk card is the newer UHS-1 type, which only benefits from faster read/write speeds when used with SD controller that supports UHS modes.

File indexing is more like smaller-file random reads, whose performance can vary wildly with the card (and controller). Advertised or rated speeds are based on larger-file sustained performance and cannot reliably be used to infer much about the smaller more random reads.
 
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lagokc

Senior member
Mar 27, 2013
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you can not go faster than this
usb flash drive will be limited always to the usb2 bus giving you max 25mb of transfer. sdhc or sdxc card will not have this limits

so 90mb transfer rate is fast enough for you?

Aren't a lot of SDHC controllers in electronics attached through a USB2 bus limiting their speed anyway? Seems like the best thing to do would be to just get a decent USB3 flash drive so files can at least be transferred TO it quickly and it will run at the maximum USB2 speed when loading songs.
 

ALIVE

Golden Member
May 21, 2012
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Aren't a lot of SDHC controllers in electronics attached through a USB2 bus limiting their speed anyway? Seems like the best thing to do would be to just get a decent USB3 flash drive so files can at least be transferred TO it quickly and it will run at the maximum USB2 speed when loading songs.

there is also a usb3 controllers and sata interface controllers
so nope it wont have a problem. but if you pair it with a usb2 yes then it will limit it down.
 

lagokc

Senior member
Mar 27, 2013
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But how prevalent are those USB3 to SDHC and sata to SDHC controllers and does OP have one of those? Seems like manufacturers like to go with the cheapest option for cases like these.
 

Insert_Nickname

Diamond Member
May 6, 2012
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But how prevalent are those USB3 to SDHC and sata to SDHC controllers and does OP have one of those? Seems like manufacturers like to go with the cheapest option for cases like these.

There are some PCIe controllers available, that can do full UHS-104. But I don't know if they are available as add-in cards.
 

corkyg

Elite Member | Peripherals
Super Moderator
Mar 4, 2000
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Is OP not limited to what his car stereo system has? As I read it, all he can add are the flash memory and SDHC cards, period. Are there not speed variances among those cards? There are in SD and CF.
 

Cerb

Elite Member
Aug 26, 2000
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What about random access? (since they are both flash memory, which is the fastest [?], it should nearly SSD speed, right?)
Random access will be faster with a fast SDHC card. A slow SDHC card will be slow.

If 32GB is enough, I'd get a SDHC by Transcend or Samsung, of a high clas rating (like 10MB/s), or lower-class-rated Sandisk or A-Data. Many makers sacrifice random performance for sequential, including Sandisk, so a Class 4 Sandisk will probably be better, overall, than a Class 10. Samsung, Transcend, and Toshiba (often hard to find) have a rep for having balanced sequential and random speeds. They might only just meet their class rating in sequential, but have fair random performance, too.

If 32GB is not enough, USB 2.0 is plain slow for random reads, even with a fast USB stick, so that would just be what you get for the option of having 64+GB on one stick.