PCI Express on old Dell - Good Enough For USB 3.0 Card?

Question

Just got a USB 3.0 1TB hard drive today, and plan on starting to digitize a lot of stuff to push out to my PS3 and Wii. Throughput is fine from a USB 2.0 standpoint, but I want to see if I can upgrade to USB 3.0

CPU-Z said that my board has a PCI Express slot for the video card, with a link width of x1 and a max supported of x16. I'm guessing that that means I've got one PCIe slot that will accept up to a x16 card. I know I'm not using it right now, as the video card in the box is an older PCI ATI card

I assume this should work, since all the cards on Newegg all run PCI Express but don't mention anything else, but I want to make sure before I plop down $30 on the card.

Answer 1

There are different revisions of the PCI-Express interface. I would expect that a USB 3.0 card will operate at PCI-E 2.0 speeds. You should look up your motherboard make & model and see what the board supports.

This said, you CAN run PCI-E 2.0 cards in PCI-E 1.0 interfaces, they're backwards compatible. I have a PCI-E 2.0 video card in a PCI-E 1.0 bus on a P4 of mine - it means the video card can't do things like load it's memory as fast as it can, but it still works and was still improved performance in my case.

Answer 2

My computer has both a PCIe slot and a PCIe X 16 slot, running XP Media Center Ed. So I bought a Kanex USB 3.0 card and installed it in the PCIe slot. It installed correctly in Device Mgr., but doesn't work with a USB 3.0 ext. hard drive. I believe the cards require PCIe 2.0 and my slot is an older PCIe 1.0. It doesn't just run slower from the card; it doesn't run at all from the 3.0 card. The same drive runs fine in 3.0 on a new computer and will run in 2.0 on the older computer when plugged into a 2.0 port. But from the 3.0 card, it gives the startup beep, but just keeps repeating it and the drive icon does not appear in My Computer.

Answer 3

Yes, it should work.

My favorite reference for this type of question is List of device bit rates on Wikipedia. According to that page, the slowest form of PCI Express (1.0 x1) supports 2 Gbit/s, while USB 3.0 supports up to 5 Gbit/s. So in theory, the PCI Express slot could be a limiting factor.

In practice, no single mechanical hard drive is going to saturate a 2 Gbit/s link, so I wouldn't worry about it.

Any PCIe expansion card will work in any PCIe slot provided the slot is "wide" enough; a x1 card will work in a x16 slot, but not the other way around. The transfer rate and number of active lanes is auto-negotiated.

If you've never seen the inside of your computer, now would be a good time. You'll have to open it anyway to install the card, so why not look at where you're planning to install it. Failing to do that is sort of like buying a sofa without thinking about where you're going to put it. If you look for yourself you don't have to guess about what CPU-Z is telling you, and you'll see if there are any physical limitations or some old forgotten card in that slot.