2018 Phone - SD Card limited to 18MB/s

[Jez_J]

Samsung Pro 128GB (95/90 R/W) will only get 18MB/s write speed on the Xperia XZ2 / XZ2 Compact. Spoke to support and they state its a 'hardware limitation'!!.

Surely this kills 4k HDR recording via SD card which is what Sony market these new phones as being capable of??

[Lord_viridis]

---

@Jez_Jwrote:

Samsung Pro 128GB (95/90 R/W) will only get 18MB/s write speed on the Xperia XZ2 / XZ2 Compact. Spoke to support and they state its a 'hardware limitation'!!.

Surely this kills 4k HDR recording via SD card which is what Sony market these new phones as being capable of??

---

No, it's more than fast enough at 18MB/S sustained write.

18MB/S provides a video bitrate speed of 144mbps which is well above the bitrate needed for 4k recording even using HLG 

[Suttoon]

The problem is that other phone companies do not have such a limit on micro SD card speeds. What about Sony's hardware creates this limit. 18mps is okay for video if consistent but it is not great for everyday usage. 

I would like to know why they limited the speed.

[Lord_viridis]

What scenario is displaying this 18MB/S write speed?

What is your EXACT card?

Where has this card been used prior at a higher speed?

[ZoroUrchin]

I have the same issue.
I'm using Sanddisk Ultra 64GB, They have claimed read speed up to 100MB/s.
But when i tested on Xperia XZ2 is limited at 18 MB/s. by using application "A1 SD Bench".

For the other devices i'm quite sure is not limited at  18 MB/s at least 40 MB/s or more. 

[ch3mn3y]

As I read on the XDA: https://forum.xda-developers.com/showpost.php?p=76526411&postcount=13

It seems to be platform limitation, not just Sonys choice?

Not sure what sharing bandwith between SD and SIM means, but there may be something like that.

[Jez_J]

Well, just flashed my phone with the Android P beta, sd speed now is 31.57MB/s read and 28.05MB/s write on a Samsung 128GB Evo Plus. Not tested the Samsung Pro yet, but the speed restriction was software related  (possibly due to Oreo formatting as exFat, Android P is fat32).

So not a 'hardware limitation' at all.....

[ZoroUrchin]

Seems Xperia XZ1 and Xperia XZ2 are have none the issues.
I'm so disappointed. If It puts limited to micro SD card bandwidth. Especially when i browse to my pictures in sd card. It feels slow to me.

XZP



XZ1

[ch3mn3y]

@ZoroUrchin

What SanDisk claims is rounded read speed, not write one.

One question about Your benchmarks - the upper is XZ2, lower XZ1? And why there is 0,00 MB/s? Maybe something wrong with the app, coz Sony changed something (connection of memories and SoC (it acts as chipset?))?

[ZoroUrchin]

@ch3mn3y What I meant is about the read speed issue. I've attached my device result.
The write speed is hit to standard of class 10/U1 specification. But i didn't test with U3/V30 standard if there limited brandwidth or not.


About the question 
All thorse picture i took it from Xperia community.  The first picture is XZP tested with samsung evo+ 128Gb. And on below is XZ1 tested with Sandisk Extream Pro.
So to the write 0.00 MB/s I think the person who did it hasn't grant a write access permission to application correctly. So that it just can't benckmark write speed.