eMMC speed?

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1

I was wondering if anyone has any number comparing the 2GB eMMCs (original BBB) and the 4GB (Rev C) eMMC speeds?

They claim it is faster but would like to see proof.

When I compared the Micron 2GB eMMC vs. the SanDisk iNAND parts of the same size the SanDisk parts smoked the Micron.

I found boot and R/W times on the Micron parts are awful. So much so even some off brand off-the-shelf standalone uSD cards show much faster boot times (just the reading phase).

Both the SanDisk and the Micron parts have the Double Data Rate (DDR) feature which would speed thing up greatly but this ability on the AM335x seems to be broken.

TI claims DDR was not implemented and should never have been included in the TRM …which I see they now have amended.

Any numbers?

2

Hi,

Just tested on my BeagleBone Black A5C with 2GB micron eMMC. Tested with latest Debian Beta booting from SD card (Samsung EVO 32GB Class 10). Here’s my numbers:

SD Read:

root@beaglebone:~# dd if=zero of=/dev/null bs=200M count=1
1+0 records in
1+0 records out
209715200 bytes (210 MB) copied, 10.9215 s, 19.2 MB/s

SD Write:

root@beaglebone:~# dd if=/dev/zero of=zero bs=200M count=1
1+0 records in
1+0 records out
209715200 bytes (210 MB) copied, 15.297 s, 13.7 MB/s

2GB eMMC Read:

root@beaglebone:~# dd if=emmc/zero of=/dev/null bs=200M count=1
1+0 records in
1+0 records out
209715200 bytes (210 MB) copied, 10.4306 s, 20.1 MB/s

2GB eMMC Write:

dd if=/dev/zero of=emmc/zero bs=200M count=1
1+0 records in
1+0 records out
209715200 bytes (210 MB) copied, 39.1959 s, 5.4 MB/s

I have 4GB Micron part (MTFC4GMDEA-4M) on my custom AM335x board (similar to BeagleBone Black design) and get this on it’s eMMC (booted to eMMC):

4GB eMMC Read:

1+0 records in
1+0 records out
209715200 bytes (210 MB) copied, 7.65176 s, 27.4 MB/s

4GB eMMC Write:

./dd if=/dev/zero of=zero bs=200M count=1
1+0 records in
1+0 records out
209715200 bytes (210 MB) copied, 20.3072 s, 10.3 MB/s

Thanks,
Dave

3

interesting numbers. What class SD card were you using for the test?

4

Hi,

We are using Micron eMMC part MTFC4GMDEA-4M (4GB version) and we are getting really low R/W numbers on custom vybrid board (Freescale Vybrid MVF51NS151CMK50 ). We are using custom software (non-Linux) on this board.

Micron eMMC:
25MB data transfer in 256KB R/W blocks. Multi-block transfer enabled in driver, using DMA.
Read 14.0964 MBytes/sec : Write 5.5438 MBytes/sec

While on 1GB MMCplus card we getting R/W
Read ~ 23 MB/s , Write ~ 10 MB/s

Can anyone point out any special fix we need to do for eMMC as MMCplus and class 10 SD cards are performing double than micron eMMC. Although eMMC datasheet claims 40 MB/s and 20MB/s for R/W but we are not even getting half of that.

Regards,
Sarfraz Ahmad

5

Pretty much disappointing numbers. ARM architecture is crap

6

It helps if you pay more $ for the good eMMC's, ones with UHS modes up
to 200Mhz...

Regards,