News Western Digital preps 4TB SD cards for 2025 — SDUC cards big enough to tackle 8K video

[Admin]

The Western Digital-owned SanDisk continues to push the envelope in SD card storage and speeds.

Western Digital preps 4TB SD cards for 2025 — SDUC cards big enough to tackle 8K video : Read more

 

[newtechldtech]

yea right , and which card reader can use that speed ? Laptops? none .. Cameras ? none ... even usb card readers are not fast enough for this.

You need to standardize the card reader speed first.

 

[pjmelect]

I was disappointed that this article did not explain how the 2TB limit was exceeded on the 4TB cards.

 

[derekullo]

I was disappointed that this article did not explain how the 2TB limit was exceeded on the 4TB cards.

SDXC has a maximum size of 2 terabytes.
SDUC has a maximum size of 128 terabytes.

https://www.sdcard.org/press/thoughtleadership/growing-demand-growing-capacity-an-introduction-to-the-new-sd-ultra-capacity-function
The SDXC spec was limited to 2TB due to its limited addressing capability – yet market needs like the trend toward 4K/8K, and the NAND technology evolutions, created a need to overcome the SDXC limit, allowing future growth up to the new limit of 128TB.

SDUC is using the exFAT file system, which is the same file system as SDXC. However, SDXC is formatted with the Master Boot Record (MBR) format. MBR format has a capacity limitation up to 2TB. SDUC is formatted with GUID Partition Table (GPT) format, which can support capacity more than 2TB.

I was under the impression that you could format an sd card to any file system you like ... zfs, but the camera/phone is probably expecting exFAT if it is obeying the standard which it is probably required to do.

Having said that if they ever do release a 128 terabyte card their Express read/write of 985 MB/s is wholly inadequate!
128TB / 985 MB/s = 36 hour 5 minute 49 second transfer !!!

 

[pjmelect]

New SD card format
I have read the above link and I think that I understand what they have done to get over the 2TB limit. They have changed the addressing on the SD card from 32bits to 64bit giving effectively unlimited size 2^64 x512 bytes which is 2.47 e173 bytes. The SD card is supplied with the EXFAT format, but could be formatted with NTFS if your device supports it as EXFAT is royalty free. I don't understand the 128TB limit as EXFAT suports drives up to 256TB. If SD cards continue increasing in size at the current rate this will become important in around ten years.

 

[usertests]

I was disappointed that this article did not explain how the 2TB limit was exceeded on the 4TB cards.

If you mean how they fit so much NAND in there, it shouldn't be too hard. There are allegedly 1.5 TB and 2 TB microSD cards on the market, and a full SD card is several times larger than that.

But these SDUC cards are compatible with almost 0% of devices and the devices that would tend to support this are likely switching to CFexpress.

 

[WeiSheiLindon]

SDXC has a maximum size of 2 terabytes.
SDUC has a maximum size of 128 terabytes.

https://www.sdcard.org/press/thoughtleadership/growing-demand-growing-capacity-an-introduction-to-the-new-sd-ultra-capacity-function
The SDXC spec was limited to 2TB due to its limited addressing capability – yet market needs like the trend toward 4K/8K, and the NAND technology evolutions, created a need to overcome the SDXC limit, allowing future growth up to the new limit of 128TB.

SDUC is using the exFAT file system, which is the same file system as SDXC. However, SDXC is formatted with the Master Boot Record (MBR) format. MBR format has a capacity limitation up to 2TB. SDUC is formatted with GUID Partition Table (GPT) format, which can support capacity more than 2TB.

I was under the impression that you could format an sd card to any file system you like ... zfs, but the camera/phone is probably expecting exFAT if it is obeying the standard which it is probably required to do.

Having said that if they ever do release a 128 terabyte card their Express read/write of 985 MB/s is wholly inadequate!
128TB / 985 MB/s = 36 hour 5 minute 49 second transfer !!!

It's important to remember where we started. When we first got the SD XC standard, not only were the first cards not nearly the full limitations on capacity of the standard, they also were quite a bit slower than the theoretical limit of UHS-I.

"Toshiba's card will be able to write data at 35MBps and read it at 60MBps. By comparison, the 333x standard used in the fastest CF cards allows for a write speed of 40MBps and a read speed of 50MBps."

Toshiba to launch first 64GB SDXC card

The manufacturer says the memory card will be the largest and fastest yet in the SDXC format

www.zdnet.com

The same applies to faster standards. While it's true that often standards such as UHS-II are developed as a necessary advancement to connect faster and faster NAND to a host device, and as such the first cards to come out often approach the theoretical limit of the spec, in the case of SD express, the standard has been developed in anticipation for the ever innovating SD card market. Most assuredly, once 985MB/s becomes a bare minimum for things such as camera SD cards, the SD association will develop and announce SD Express 2.0, similar to the logical step from PCIE 3.0 x4 to PCIE 4.0 x4 for m.2 SSDs. This will happen long long before 128TB SD Cards are even partially realistic.