Hi everyone, a few days ago i bought a sandisk micro sdxc 64gb uhs-1 class for my android. I connected it to my pc using the adapter that came with the package. Apparently it's an original card, i sent an email to sandisk with the serial number to verify whether it's original or not:
http://www.sandisk.com/products/memory-cards/microsd/ultra-class10-with-adapter/?capacity=64GBSo, i connected it with the adapter, and formatted using EaseUS Partition Master Free Edition 10.0. I chose fat32 with the cluster size of 32k and then started to use with my device. The first problem is that the transfer speed is really slow. It takes twice the time comparing to my other sandisk sdhc 32gb, also class10. I used the same cable and connected both of them into my notebook, and this issue persists. My other sandisk 32gb is twice faster. I've been playing need for speed most wanted, which installs 2gb of data into the sdcard, and occasionally i'm getting these hiccups which makes me wonder if this is related to the sdcard.
I've been doing some research using google while i'm waiting for sandisk's answer and i found an interesting topic at the xda developers, here:
http://forum.xda-developers.com/showthread.php?t=1699511&page=3Someone says:
In my opinion the Sandisk 64gb class 10 uhs-1 cards are really crappy. Speeds are horrible and rarely will u see 10MB/s write and your cluster size has to be below 8KB more like 4KB is ideal. If it's any higher performance takes a HUGE nose dive. Even with mine setup Perfectly I still get about 2MB/s writing a whole bunch of small files. I get about 5MB/s music transfers, and right At 10.0MB/s MAXIMUM. My Wintec 32GB Class 10 would write music at 7-9MB/s, small files at 5-6MB/s, and big files at 15-20MB/s and that's on a 64KB Cluster size.
Because the Sandisk performs worse on large clusters it's clear there are internal engineering faults on these cards. The larger the cluster size the faster large files will copy. Small files may perform a tiny bit worse on a 64KB cluster but it okay since we have to deal with that no matter what device your using. Bigger is In Fact Better. However the Sandisk class 10 64gb card pulls off 1MB/s on small files, 3MB/s on music, and a MAX write speed of only 7MB/s on 64KB Cluster Size. I tested all cluster sizes and all files sizes and speeds. To come to my dreary conclusion that Cluster Size 8KB,4KB,2KB,1KB provide barely acceptable performance. Meaning small file sizes are always slow but with the 64kb clusters it was about 1MB/s write, Medium file sizes at about 3MB/s, and large files at 7.0MB/s. Changing the cluster size to 32KB, and 16KB resulted in the same poor performance. Once I went to 8KB large file sizes are fastest at 8KB u can see right away 10-13MB/s write with an 8 or 4KB cluster. With the 1KB, and 2KB Cluster it takes a while to build up to right about 7-10MB/s. On the 1KB,2KB clusters get about 3-5MB/s on small files, medium at 5-6MB/s, large at 7-10MB/s. That's why I feel 8KB cluster if u want the fastest possible write speed on big files and moderate small to medium file size performance. The 1KB,2KB cluster perform better than the 4KB and 8KB on small files sizes but performs worse than the 4KB/8KB on large files. So overall 8KB is ideal for max large file performance, 4KB provides 90% of what 8KB can do on large files, but performs 1-5% better on small and medium file sizes. I stick with the 8KB cluster myself.
The only thing that I can think of is were dealing with a Solid State Disk data chip which is like an SSD hard drive. If the partitions are not PERFECTLY aligned in the hardware firmware flash then we the user get to deal with poor performance. So I downloaded a program called Paragon Partition Aligner tool and I'll give it a shot to see if the Bytes and clusters are out-of-line.
later
Let's get some details out and compare the numbers and specs.
It seems that it wasn't a good idea to buy the sandisk 64gb sdcard. I'll try changing the cluster size to 8kb to verify if this will help to get a better transfer speed. What do you guys think? Will this help? Is it a good idea to reduce the cluster size? I thought that larger cluster size would help when transferring big files.
Also, what's the better format for a 64gb card? Should i stay with the fat32? Change to exfat? NTFS? Some other extensions like ext3 or ext4? Any help is welcome. Thanks.
