usb 3 addon card

[bassfisher6522]

If I add a usb 3.0 add-on card to my desktop will I loose any speed on the card or would the bus speed of the pci slot make any difference one way or another.

 

[theog]

Not seen a usb 3.0 PCI card, only PCI-e x 1.

 

[fireberd]

And, if you don't have any USB 3.0 devices you don't need it. Hooking USB 2.0 devices to a 3.0 port will only run at the 2.0 device's speed.

 

[bobafetthotmail]

Depends. you mean PCI? Then the main bottleneck is the PCI slot itself, and anything that fits will perform the same. Like say this, that is honest enough to claim that the actual speed is around 1 Gbps, not 5 like real USB 3.

If you are talking of PCI-express, then there are more considerations. For the best speed you need to hunt for the ones that have a good PCI-e (PCI-e 1.0 sucks, 2.0 is ok, as long as your mobo has PCI-e 2.0 slots anyway), and one that has a controller per port (as otherwise the total bandwith is shared through all ports connected to a single controller).

This article goes more in depth, and reviews a good USB 3 card.

 

[bassfisher6522]

I have two PCIe X1 slots and 2 PCI slot available. Yes, the only usb 3 card I've found is for the PCIe X1 slot. So again my to my question about the bus speed and what are the actual bus speeds.

 

[GeneO]

Your motherboard has PCI-E 2.0 for which the bus speed for a single lane is 500 MB/s - more bandwidth than you will get from any single device.

USB 3.0 itself is capable of around 400 MB/s. So, in principle, the PCI-e bandwidth should be able to give you full USB 3.0 speeds.

 

[whs]

USB3 seems to have a lot of overhead. I compared it to eSata and it was a lot slower - although the specs would lead you to believe the opposite.

If you have no USB3 gear yet, I would lean towards an eSata card and the corresponding gear.

 

[GeneO]

That may be so, USB overheads aare kind of high. But I don;t think there is any difference over eSATA unless you are using a very high speed SSD over USB. In addition, eSATA requires an external power source whereas USB 3.0 is powered via USB and needs no additional power sources.

 

[whs]

Gene, you got a valid point. The speed differences showed especially when I was imaging to a SSD in an external dock. I wanted to test the limits. But even with normal HDDs I noticed a difference to the advantage of eSata.

The power supply point does not apply to my paticular setup. All my docks have external power. But for e.g a laptop, USB3 may be an advantage.

 

[bobafetthotmail]

I have two PCIe X1 slots and 2 PCI slot available. Yes, the only usb 3 card I've found is for the PCIe X1 slot. So again my to my question about the bus speed and what are the actual bus speeds.

Did you read the article I linked? It depends on PCIe version/generation (look at the box to the right)

The relevant part from the article I linked in the post above
------
First off, never under any circumstances limit a USB Controller to PCI Express 1.0 x1 bandwidth (250MBps). With Gen1 slots, I've seen file transfers hit walls of 90MBps during write tests that were only ever alleviated by switching over to a PCIe 2.0 x1 slot (500MBps). USB 3.0 is rated for 640MBps (5Gbit/s) anyway plus the controllers are usually connected natively by PCIe 2.0 x1, so it makes no sense to limit yourself.
-----

You need to know the card's and the motherboard slot's PCIe version/generation, if it's Gen 2 or ver 2.0 or better it won't limit it, if not it sucks.

 

[GeneO]

As I mentioned, the OP MB is PCI-e 2.0. No manufacturer will make a USB 3.0 card with a PCI-e 1.x interface, PCI-e 2.0 has been out for quite sometime and is even being supplanted by PCI-e 3.0 now.