P5E-WS: ESATA speed

[mis33]

I just bought a Antec MX-1 hard disk enclosure to house a WD50000AAKS. When I rebooted my PC, I saw that the Marvel driver was installed during boot time.

I copied 21GB from my local drive to this external drive and it took 6 minutes. Not even close to the 3 GB/S as per SATA-2 standard. When I connected the HDD to a USB-2 port, the same data would take 14 minutes to copy.

The ESATA transfer rate does not even come close to the SATA standard of 3 GB/S. Is this a problem with the Marvel driver? If I use a ESATA bracket to connerct the external HDD to one of the 6 internal SATA ports, would this improve the transfer rate?

 

[techgeek]

Umm you realize that you will never max out the SATA bus speed. Hell todays drives couldn't max out IDE. Not only that but SATA does not do 3 G Bytes (capital B denotes bytes not bits) is 300MB/s for SATA II. Now with that hard disks are limited by the fact that they are a mechanical system, their rotational speeds can not approach the speed needed to saturate the SATA bus (the typical rotational speed for desktop drives is 7200RPM and WD Raptors are 10K). Most new drives don't reach beyond 75-80MB/s. If you want faster you have to go SCSI with rotational speeds of 15K RPM, or do RAID 0. The SATA bus speeds are only worth considering when writing small files (small enough not to overflow the buffer) or reading small files that happen to be in the drives buffer. Any sustained write/reads will have to access data from the drive platters themselves which is limited by it's access time + rotational speed.

So to transfer your data (21GB) at a sustained transfer rate of 65MB/s (typical), it would take approximately 5 minutes 40 seconds. Given the fact that I don't know where on the platter you data lies (outside of the platter gives fastest speeds) and I don't have knowledge of how fast your HDD actually is, this is an educated guess. Saying that, it seems consistent with what you have stated. As for USB, the very maximum you can transfer over USB 2.0 is 60MB/s. That is ideal based on the maximum bandwidth of 480Mb/s, you will never reach that speed. It's more than likely that you might see 30MB/s, so USB will be much slower than ESATA (take approximately twice as long).

 

[mis33]

You are right. I forgot about the bit/byte differences.
I use HD Tune 2.54 to benchmark my 2 drives:

HD Tune: WDC WD7500AAKS-00RBA Benchmark (SATA)

Transfer Rate Minimum : 48.4 MB/sec
Transfer Rate Maximum : 97.1 MB/sec
Transfer Rate Average : 76.8 MB/sec
Access Time : 13.8 ms
Burst Rate : 124.4 MB/sec
CPU Usage : 1.1%

HD Tune: WDC WD5000AAKS-22TMA Benchmark (ESATA)

Transfer Rate Minimum : 39.0 MB/sec
Transfer Rate Maximum : 81.9 MB/sec
Transfer Rate Average : 66.4 MB/sec
Access Time : 13.4 ms
Burst Rate : 99.9 MB/sec
CPU Usage : 1.6%

The internal SATA port (South Bridge as opp0sed to Marvell) is faster. Maybe I should use a ESATA bracket to connect the external drive to one of these SATA ports.

 

[bobbknight]

Also realize that windows imparts an I/O overhead to any read write operation to the storage system.

 

[mis33]

I have 2 hard disks:
1. Internal: WD7500AAKS (SATA)
2. External: WD5000AAKS (ESATA)

When I copied the 21 GB (8 files), I did it from WD7500AAKS to WD5000AAKS.

 

[mis33]

Actually, this is a new build and I tried to find out if the speeds are OK.

I know the Raptors are faster because they are 10K RPM drive.