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What Are Your SD Card Slot Read/Write Times? Mine R Slowwww....

ChrisPanzer

Active Member
Perhaps this is typical, or normal, by my SDXC card slot has the standard SanDisk 128GB MicroSD card inside it, and whilst using HD Tune Pro, Im getting 30-40MB/sec read/write times, which are mainly 'burst' rates, as the rate drops every few seconds and then spikes anywhere between 30-40MB, which needless to say makes for error-prone writing/program downloading/streaming/etc.

To put that in perspective, the internal SSD 256GB SP3 drive gets anywhere between 200-300MB/second read/write times.

With that being said, the drive is basically unusable, for anything other than archival storage.

Questions:
1) Is this normal/typical of this drive?
2) Why is there such a difference between the two memories? Why can't they make SD card slot thats just as quick as the SSD?
3) Is there anything I can do to improve data transfer times?

Thank you!
 

jnjroach

Administrator
Staff member
The SD Card is on the USB Internal Hub and it tends not to use the same level of NAND Memory as an SSD. I only use my SD Card for file storage including Office Files, Pictures, Music and Movies all work without issue. I don't try to use it to run programs from though.
 
OP
ChrisPanzer

ChrisPanzer

Active Member
It's just ridiculous.

I installed iTunes last night on my SP3 (GASP! I know it was for my wife). I installed it on the SDcard first, which took quite a long time, I'd say about 5-8 minutes. Then I uninstalled, then re-installed on the SSD. The installation from start to finish took less than 1 minute.

That difference is ridiculous to me. Like you say, other than storage, the drive is untenable for any other purpose, and with the spike speeds it makes it even more less-viable for streaming, video playing, photo editing, etc.
 

wditters

Active Member
Questions:
1) Is this normal/typical of this drive?
Yes, SD card technology simply is not the same as SSD technology. Different flash modules, different controllers, different footprint, different everything. Within the constsraints of that technology however there are differences in SDcards. The Sandisk Extreme range typically is capable of offering twice the speed of the standard and ultra range (if the controller also can)
2) Why is there such a difference between the two memories? Why can't they make SD card slot thats just as quick as the SSD?
That would result in larger cards containing more technology. That would defeat the purpose as Micro SD cards typically are used in smartphones, digital cameras etc.
3) Is there anything I can do to improve data transfer times?
Only to purchase the higher end models (Sandisk Extreme) (although your mileage might still vary)
 

ptrkhh

Active Member
Roughly, SSD is like several SD card chips ran in RAID0, that's why its fast. And that's why larger SSDs are often faster than the slower ones, simply because there are more chips in there. Unfortunately, you wont be able to fit all of that in a card the size of a fingernail.

To be able to manage all the chips working together in the most efficient manner, as well as to optimize the performance and reliability (since its often used for system drive), it also packs a controller. The controllers often have clever functionalities like wear-leveling and even compression. The most popular (and controversial) SSD controller manufacturer is SandForce, powering almost all SSDs other than Samsung's. HDD and SD don't have dedicated controllers like that, that's why they require maintenance from the OS (defragmenting a HDD), and often don't last as long (SD card).

Oh, and SSD has a DRAM cache. To make it even faster.

tldr: SSD can be faster because its more complex, and it packs more components, hence its bigger. Its impossible today to build an SSD the size of a microSD.
 
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GreyFox7

Super Moderator
Staff member
Seed depends on which card exactly
SanDisk Ultra 128GB MicroSDXC Up To 30MB/s Read Speed.
SanDisk Extreme 128GB UHS-I/U3 SDXC Up To 60MB/s Read; 40MB/s Write
SanDisk Extreme PRO 128GB UHS-1/U3 SDXC Read Up To 90MB/s/ Write Up To 95MB/s

Note the words Up to.

If it conforms to the advertised spec you got what you paid for.
 

bluegrass

Well-Known Member
I have always used SD cards to only store data and nothing that requires high speed transfer. They might work well for storing MP3 files and certain video files.
 

Nicola

Member
Well, I've noticed this too. I had to swap data across two microSD's and when inserted in the SP3 they were sensibly slower then in my 5yo Vaio (using the microSD to SD adapter)
 

Spider

Super Moderator
Staff member
Like you say, other than storage, the drive is untenable for any other purpose, and with the spike speeds it makes it even more less-viable for streaming, video playing, photo editing, etc.

An external Micro SD Card (MSD) AKA TF Card (128GB in your case) is and always was intended as space to store media files. Books, pictures, videos, movies, music files, backups etc. are what you should be putting there.
 

Ordnas

Member
Does anyone know if the sd card slot is able to reach 90mbs write speeds if used in conjuction with a 90mbs micro sd card?
 

GreyFox7

Super Moderator
Staff member
Does anyone know if the sd card slot is able to reach 90mbs write speeds if used in conjuction with a 90mbs micro sd card?

Didn't make it, only 76.15 MBps With Samsung 64GB Pro.
CrystalDisk SDcard.PNG
 
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