The best option for fastest speed is to boot using the sd-card but file system mount using a solid-state sata drive - there are drives that we have tested at the $130 price range from OWC (Other World Computing) that give VERY GOOD performance. The next best option is to use a notebook sata drive like the Segate Momentus 500GB drive with 4GB cache for around $80. The large cache is important for overall performance using traditional spinning drive technology. Our performance data indicates only a 20% drop in performance with the Momentus against the pure solid-state drive. If you want decent performance, FORGET FILE SYSTEM MOUNTING FROM THE SD-CARD; even class-10 cards are dogs compared with notebook sata's.
Scott
Regarding the "you need a micro": Yes and no ;)
Please refer to what I mentioned above: Full size SD cards are available with higher speed than micro SD cards (micro: class 6, full size: class 10). Therefore I proposed: Boot from a class 6 micro SD. Use this only for U-Boot and kernel. Then let the kernel mount the rootfs from a high speed class 10 full size SD card.
Well, you probably need micro, so look at theses class 6 micros:
Maybe you like to try a class 10 card. E.g.
Transcend 8 GB Class 10 SDHC Flash Memory Card TS8GSDHC10E
Guys,
We tested a few SD cards and correlated the UI speed and the speed of which programs (like firefox) load with the minimum read rate of the SD card, suggesting that the file size transfers are very small for these operations.
Firefox load time on SD cards
Transcend (Class 2) 4GB - 9s
Sandisk (Class 2) 4GB - 10s
Kingston (Class 2) 4Gb - 21s
Transcend Benchmark
SanDisk Benchmark
Kingston Benchmark
Unfortunately many of the i.MX53 QSBs were shipped with the Kingston, but I would now suggest to use a SD card with higher minimum transfer rate such as the Transcend or SanDisk.
If anyone finds a SD card that performs even better then please post it here.
Regarding the performance of the QSB with SD cards I learned that there are two topics:
- You should use a as fast as possible SD card
- Full size SD cards are available with higher speed than micro SD cards
For the QSB this does mean: It boots from the micro SD. Use this only for U-Boot and kernel. Then let the kernel mount the rootfs from a high speed class 10 full size SD card.
Regarding using other media for the rootfs (USB sticks, SSDs, SATA disks etc) I have no experience.
Jeff,
Well thanks for the tip. If you read the reviews on Amazon, it really leaves you wondering what the class even means.
I would also be interested to know why the full size slot is not usable (I have some 8GB full size cards that I bought for another project).
--Jim
Jim,
I bought a Class 2, 4GB transcend micro SD card from amazon for $7 and performance is around 20 times better. The class 2 san disk are much better also then the Kingston card. You are right however you can't depend too much on the class rating but the chances are better.
Jeff,
Yes, I know about crappy SD cards - you wouldn't be the first to get caught on that.
I have a 32G SSD that I plan to use, but I do look forward to hearing what you find out, like the "other factor".
It would be really great if you could recommend a specific brand, as you may not even be able to rely on the stated class of the SD card.
--Jim
Jim,
We are aware of this issue and we are tracking the root cause to low quality microSD cards that come with the QSB. If you use a higher class micro like a class 4 or higher you will notice a huge performance increase.
We are also looking into another factor that might be causing this issue and I will post the analysis if deemed relevant. However for now please use a better quality microSD card.
BR,
Jeff