Samsung 840 512GB slow on USB3

[alexan]

I have a new Samsung 840 SSD with a capacity of 512GB. I use it in an external enclosure, Oyen MiniPro 2.5 (see http://oyendigital.com/hard-drives/store/U32-M.html). The SATA-USB3 chip in the enclosure is Asmedia 1051E, which is supposed to support up to SATA III speeds.

I attached this disk to a Windows 7 machine. This machine did not have USB3 ports originally but I used the PCI card that came with another external disk I bought earlier (http://www.newegg.com/Product/Produc...82E16822215059). The PCI card is a 2-port PCIe Host card, with 2 USB3 ports. This card uses an USB3 chipset NEC/Renesas uPD720200 chip.

I have a small 100GB FAT partition on this disk. I use CrystalDiskMark to measure the bandwidth and I find for sequential transfers 140MB/s reads and 110MB/s writers. This is close to what I measured using ATTO disk benchmark.

I expected the transfer rates to be much larger. Am I doing something wrong or this is what I should be expecting?

 

[kbp]

That probably all you are going to get out of a USB-3 port.

 

[yefi]

It looks like the uPD720200 can do about 200 MB/s, so, assuming all your drivers are up-to-date, the limiting factor must be the enclosure.

 

[tcsenter]

SATA 6Gbps <-> USB3.0 <-> USB3.0 <-> PCIe x1 (v1.1 I presume) = much slowed

 

[hhhd1]

Most sata-2-usb i have seen have been SATA1 (1.5), which has maximum speed of 150MB/s

 

[Engineer]

Most sata-2-usb i have seen have been SATA1 (1.5), which has maximum speed of 150MB/s

I was going to post the same thing but the link in the OP for the case suggests that the interface is SATA III.

Ports:USB 3.0 (Up to 4.8 Gbps)
Interface:SATA III (9.5mm or 12.5mm SATA HDDs)
Interface:4.9 x 3.1 x .9 inches
Chipset:ASMedia 1051e
Weight:10 oz.
Certifications:CE, FCC
Requirements:Compatible with Windows XP/Vista/7 & above; MAC OS 10.2 & above; Linux 2.4.22 & above.

Doesn't mean that it 100% but it is listed under the specs nonetheless.

 

[alexan]

SATA 6Gbps <-> USB3.0 <-> USB3.0 <-> PCIe x1 (v1.1 I presume) = much slowed

The PCIe slot is indeed is indeed x1 v1, but this is supposed to support up to 250MB/s in each direction (http://en.wikipedia.org/wiki/PCI_Express#PCI_Express_1.0a).

 

[tcsenter]

The PCIe slot is indeed is indeed x1 v1, but this is supposed to support up to 250MB/s in each direction (http://en.wikipedia.org/wiki/PCI_Express#PCI_Express_1.0a).

All these conversions are not cost-free. But it seems to be performing a little below what I would've guessed. You can try to update the firmware and drivers for the PCIe Renesas/NEC card, if you want to take a little risk of updating the firmware:

Latest drivers and firmware from unofficial source

Renesas/NEC uPD720200/A Firmware Update Tips

The USB3.0->SATA converter chip used in the external enclosure may be the issue. Back when USB2.0 was relatively new, the early converter chips for those were not as good as later generations.

 

[alexan]

You can try to update the firmware and drivers for the PCIe Renesas/NEC card, if you want to take a little risk of updating the firmware:

Latest drivers and firmware from unofficial source

Renesas/NEC uPD720200/A Firmware Update Tips

The performance I quoted is after upgrading to the latest firmware and drivers from the station-drivers webpage mentioned above. The upgrade did not improve the performance much (the change was at the 1% level).

 

[groberts101]

too much hardware communication = cumulative lossses as mentioned above.

Plus.. the card you have(actually the Renesas chip it uses) seems to be slightly slower than the ASMedia chip to begin with.

Also consider that USB 3.0 is not all that and a bag of chips without UASP support. That can really make it fly like you'd think it should out of the box.