I’ve seen a lot of people post about slowness on their speedy drive.
There are a few reasons for why this is happening:
1: It’s plugged in a USB 2.0 slot. Generally, USB 3.0 slots are marked with a blue color, or they will have “SS”/“SuperSpeed” logo near them. Sometimes they will not, but this is fairly rare.
2: Chipset drivers. This is fairly common with fresh installs of windows 7, and sometimes with windows 8 depending on how new the motherboard is. Install USB 3.0 drivers and the speed will come back.
3: The device you are reading or writing to just isn’t fast enough. This is going to be the most common reason the transfer is slow for platter drives. The fastest platter drive with zero fragmentation is going to max out around 150-170 MB/s, the average consumer drive is going to be closer to 100-120 MB/s, and when fragmentation is thrown in that could be as low as 30-70 MB/s.
Sector size is a bunch of ■■■■. I’ve set my device to NTFS 4k, NTFS 32k, FAT32 32k, all 3 had the same sustained transfer rates of around 190 MB/s. Sure, there may be minor differences, and I suppose in the right situation/environment it could make a significant difference, but for a majority of people it will not change anything. Which, if you guys want an easy way to format the device into whatever file system - Rufus - http://rufus.akeo.ie/ will do anything you want.
4: The Sandisk Extreme 64 GB is literally a SSD hard drive on a USB Stick, except that there is no easy way to force the drive to perform a TRIM operation. - https://en.wikipedia.org/wiki/Trim_(computing)
#4 is the one that will catch people eventually. The lack of trim support in windows really hurts the speed of the drive over time. Formatting the drive will not fix this, no matter how you format the drive. As the drive is used over time, and files are deleted in windows from the drive, windows never tells the controller on the drive where it has deleted files. So, it starts to stumble over itself trying to find empty space to put new files.
I’m honestly not sure if there is a way to force TRIM on the drive. However, there is a workaround, but unfortunately it’s not the easiest thing to do.
SecureErase.
SecureErase sends a command to the controller on the SSD, telling it to “shock” the drive and wipe everything on it. This resets everything on the drive, and effectively makes it brand-new again. Just be warned that it will not have a file system, it will be a raw drive that you will have to format to NTFS/FAT32.
Also, be warned that there are a lot of programs that use the words “SecureErase”, but they do not perform the function I mention above.
Unfortunately the only easy way to do this command is with parted magic.
http://www.overclock.net/t/1227597/how-to-secure-erase-your-solid-state-drive-ssd-with-parted-magic
Parted magic is so far the only thing I have seen that correctly sees the Flash drive as a SSD device with secure erase capability. However, it works. After a month of heavy-use, I was starting to get 20-30 MB/s write speeds on my device, and after running parted magic, the device was back to 190 MB/s.
(Part of the reason I’m posting here is hoping that someone has found a way to force trim/secureerase inside of Windows. 
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