04-25-2014 07:23 PM - edited 04-25-2014 09:46 PM
After looking in the device manager as per your suggestion, it appears that I have a Samsung/Seagate HN-M750MBB/ST750LM022 drive. (the first part number is the Samsung number, the second is the Seagate part number).
The specs are SATA, 3.0 Gbps, 8MB cache DRAM buffer, 5400 rpm
spin-up current is 1000 mA with the seek, read/write, low power idle, standby, and sleep currents all considerably less than 1000 mA.
Since the transfer rate is 3.0 Gbps, I assume this is only SATA II since SATA III would be specified as 6.0 Gbps.
To use this hard drive in an external enclosure I would need a USB cable that has a "Y" that brings the USB port power from a second USB port so that the parallel combination of plugging the "Y" cable into two USB ports would give a total power of 1800 mA (if dual USB 3.0) or 1200 mA if a combination of 1 USB 3.0 and 1 USB 2.0 is used (the power-only part of the "Y" USB cable going to the USB 2.0 port), since a USB 2.0 port only supplies 500 mA whereas each USB 3.0 port would supply 900 mA. Using a "Y" cable with two USB ports would ensure enough current for drive spin-up.
Looks like the hard drive installed can be used in an external enclosure with the above mentioned "Y" USB cable since two USB ports would supply sufficient current for drive spin-up.
Thanks so much for the tip of using the device manager to find the drive part number. Sure would not have liked to have to disassemble the laptop to find the part number label on the physical drive.
04-25-2014 08:59 PM - edited 04-25-2014 09:50 PM
There is one wrinkle here:
While I have the Intel series 8 Chipset that gives the SATA III support for the disk controller, a review of the hard drive specifications for the installed drive show that its transfer speed is 3.0 Gbps, which is the SATA II speed. SATA III would be 6.0 Gbps, so the drive must not support the full SATA III transfer rates.
So, it seems that while the drive controller would support a faster drive, my hard drive performance is limited by the fact that a SATA II drive was installed rather than one that would support the SATA III speeds.
The net result is that hard drive transfer speeds will be limited by the slowest device in the disk/controller chain, which in this case is the hard drive.
I could install an SSD externally on one of the USB 3.0 ports and get the same transfer speeds as the SATA II hard drive from the SSD, since USB 3.0 has a 3 Gbps transfer speed also, same as SATA II.
Might just get a small performance boost booting from an external SSD just because the SSD access times may be a little faster than the hard drive seek time.
Have to do some benchmarking to prove it though.
The upside is that if an SSD supporting SATA III were installed internally, I could realize the full SATA III performance speed.
05-02-2014 07:03 AM - edited 05-02-2014 07:05 AM
One final note to add to this thread (or at least I hope its final!).
The hard drive installed in my laptop, as I learned from the device manager, is the Samsung/Seagate HN-M750MBB/ST750LM022. The data sheet for the hard drive gives its interface as Serial ATA 3.0 Gb/s interface.
The SATA 3.0 Gb/s interface is, unfortunately, SATA II. While the motherboard supports SATA III (SATA III would be the Serial ATA 6.0 Gb/s interface), since the hard drive only supports up to SATA II speeds, the drive in this laptop is not going to perform up to the performance capabilities of the installed motherboard.
Unfortunate, but it is what it is. I probably would have made a different purchasing decision had I known this up front, since most applications' performance is disk bound, and a higher speed disk would boost performance considerably.
It is unfortunate that when one tries to make purchasing decisions, one cannot get detailed enough specifications on the installed hardware to fully understand what one is buying. A great example is that for my specific model laptop, the only way to find out the model hard drive installed was to either look in device manager (which requires you to already have the hardware in hand) or open up the computer to read the label on the hard drive (which also requires you to already have the hardware in hand).
At no time during my study of the specification for this laptop was I able to find any real details about hardware in the HP service manual on line, simply because the service manuals typically have HP part numbers which do not cross reference to manufacturer's part numbers to allow one to see the full set of specifications, and the service manual did not have sufficient detail on specifications such as hard drive interface speeds, current draw, and so forth.
Sadly I have to learn everything after the fact of purchase.
As for calling HP to find out, its been my experience that sales support generally has even less knowledge about hardware specifications than the service manuals.