Mark,
I have an old (circa 2007-08) desktop computer that I retrofitted with
a USB card in the PCIe x1 slot.
Yes, there is some speed limit compared to the _theoretical_ maximum
bandwidth of USB 3.0, but in reality it doesn't matter as the drives do
not have that throughput anyway.
And the advantage over USB-2 is very noticeable.
(And no, in this case, I wouldn't bother with the legacy PCI slots)
I don't remember the reason, but I remember that I decided not
to buy a card with more than 2 USB ports.
(It was likely for one of the following reasons:
1) insufficient power for more than 2 mobile drives, - a powered
hub does the job, see blelow)
2) those were unavailable (for PCIe-x1) or impractical. )
I haven't bothered to put two cards. For your two HDDs, I'd suggest you
try with one first, and only if it is insufficient, you go for the second.
I don't know for sure how much speed advantage two cards would offer over
one, if at all.
Here is the card I bought in November 2012 for 12.03 at B&H. It is now
$12.99 there.
Transcend 2-Port USB 3.0 PCI Express Expansion Card
http://www.bhphotovideo.com/c/product/696114-REG/Transcend_TS_PDU3_2_Port_USB_3_0_PCI.html
I haven't used it heavily, but I am happy with the purchase, it is
adequate for what it is.
I've also been using a USB-3.0 hub (although mostly with my laptop).
Since you mentioned you are interested in one, here is the info.
USB-3.0 hub with 7 ports and 25 W external power.
The power is important with the [mobile] HDDs that don't have their own
power supplies (I have at least 2 of those).
Plugable Model: USB3-HUB7-81x
http://www.amazon.com/Plugable-SuperSpeed-Adapter-Charging-Support/dp/B008ZGKWQI/ref=sr_1_2?ie=UTF8&qid=1436289196&sr=8-2&keywords=plugable
And while we are on the subject, - last December I bought this USB-3.0
SD-card reader (compatible with SDXC, etc., and UHS-1 capable, AFAIK):
Trancend TS-RDF8K
It is available for about $13 on Amazon, and I am very happy with it.
http://www.amazon.com/Transcend-Super-Multi-Card-Reader-TS-RDF8K/dp/B0056TYRMW/
It seems to be faster than all my cards (including UHS-1). I wrote about
it on PDML earlier, as a feedback response to Rob S., who recommended
this card reader when I was looking for one.
I would buy all three devices again.
HTH,
Igor
PS. As for the MoBo-upgrade idea, - beware of some caveats: you'd have to
check the compatibility with the existing CPU, memory, and the power
supply.
(There is a chance that the old power supply may not have sufficient
wattage for the newer motherboard, especially if you have
plenty of other power-hungry devices (video-card, HDDs) added/upgraded
since the computer was assembled at the beginning.)
On July 6, 2015 8:17:03 PM MST, Mark C wrote:
I'm fixing to upgrade my circa 2009 PC with a USB 3.0 card. Knowing that
there are many people here who understand this stuff better than I do -
a few off topic questions... (since the USB card will be used to support
drives that will store photos taken with my Pentax gear, it's not
completely off topic...)
It seems that you need at least a PCIe 2.0 slot with 5 GBps throughput
to get full USB 3.0 speed. My PC only has two free PCIe 2.0 x1 slots
@2.5 GBps each. The sole PCIe 2.0 x16 slot is occupied by the video
card. There are also a couple free legacy PCI slots - I think they are
32 bit PCI slots. (The mother board manual simply calls them "PCI
slots").
Adding a USB 3.0 card to one of the free PCIe x1 slots seems to be the
obvious route to go. With PCIe x1 I will only get 50% of the possible
maximum throughput. Based on what I read - that will still be a good bit
faster than USB 2.0... If USB 3.0 is theoretically 10x faster than USB
2.0, then my theoretical increase will be 5x.... is that right?
Would there be any point in even considering adding a USB 3.0 card to a
legacy PCI slot? As best I can tell PCI has a maximum of 133MB/s or
roughly 1 GBps so USB 3.0 on a PCI bus could be about twice as fast as
USB 2.0??? I assume far short of the increase expected from using a PCIe
x1 slot...
As I understand it, each USB controller splits the bandwidth between all
active devices connected to it. So if I am copying files between two USB
drives hooked up to a single USB controller the bandwidth would be split
between them. That makes me wonder - if I add two USB 3.0 cards to my PC
- one in each of the free PCIe x1 slots - and put one drive on each card,
will that result in each controller running at full speed when copying
from drive to drive? That would be as fast as copying between two drives
on a single controller running off a full speed PCIe 2.0 slot. Is my
thinking right on that point? Since the USB cards are about $20 each,
I'd give that a try if it would speed things up.
Lastly - is there anything in particular - e.g. desirable chip sets or
features or brands to avoid - in USB cards and hubs? (I plan to add at
least one card and one external hub.)
Thanks!
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