Disk speeds

Is it reasonable for a USB 3.0-attached external drive to have a significantly higher read rate than a SATA III 7200 RPM internal drive? I ran a disk speed test using the ToTuSoft Lan Speed Test(lite) and got the following results:

Test File: D:\Speed test.dat\NW_SpeedTest.dat
Write Time = 0.0092875 Seconds
Write Speed = 17,227.4701920 Mbps
Read Time = 0.1763921 Seconds
Read Speed = 907.0701040 Mbps

Test File: E:\Speed test\NW_SpeedTest.dat
Write Time = 0.0996091 Seconds
Write Speed = 1,606.2784160 Mbps
Read Time = 0.0857151 Seconds
Read Speed = 1,866.6495440 Mbps

where the D drive is an internal SATA III Western Digital WD1002FAEX-00Z3A0 (1 GB, 7200 RPM), and the E drive is a Western Digital USB 3.0 3 GB MyBook.

I used this test program because it supported internal drives, USB-attached drives, and NAS drives, but I suspect the numbers are bogus. It claims to bypass buffering, but I bet it does not. I tried it on other drives on another PC (SSDs and HDDs, but with only SATA II support). The numbers were different, of course, but the reported write time was always significantly higher than the read speed. That makes no sense to me unless the data is buffered without the program knowing it.

Is there a more reliable (free) program that doesn't require an advanced degree in Diskology to understand? I tried the Microsoft Diskspd but had no idea what parameters to give it and couldn't understand any of its output.

Without researching that program, it appears to be a network speed test, not a disk-based test. You will likely want something like this app. It's free and works with all types of hard drives.

Download ATTO Disk Benchmark - MajorGeeks