Ok, I have your answer better than these. USB offers convenience, but is also limited to the speed of your USB. Look up data transfer speeds for USB, USB 2.0 and USB 3.0. PCI is limited to what your motherboard can handle, which is substantially more. If you're gonna be dealing with a slower connection, then I suppose it doesn't really matter that much, but if you're gonna be hotspotting on at least a halfway decent 4G, then you have these things to consider. Also, if you're simultaneously using another USB port, especially on an older PC, that could end up throttling both your Wi-Fi speeds and your data transfer speeds if both are used simultaneously. PCI is quick and rather easy to install. I'd only go USB if I was planning on using on multiple PC's. USB 1.0 was either 1.5 or max of 12Mbps. That's Mbps, not to be confused with MBps. bits and Bytes. 8Mb = 1MB Megabit and MegaByte. So, basically USB 1.0 will only give you speeds to stream very low res video, if you're lucky and forget about Netflix. USB 2.0 is much faster, but still, many factors affect the actual speed you'll get. USB 3.0 would do alright, depending on your needs of other USB devices connected. Simple Google search can verify everything I've said. Good luck guy and just FYI, the PCI card the last answer mentioned may be a bit over the top for your needs. That's somethings you'd get if you were running 100MBps internet doing online gaming on a powerful, newer gaming PC. A simple one would be plenty. Besides, even if you had those speeds, an older PC couldn't make use of them as even the bridge on the motherboard isn't gonna be able to transfer those speeds. That's a 1.3Gbps wifi card. I mean, seriously guys, do you just have too much money on hand and not have a clue what you're really getting? If so, contact me and I'll set you up with same exact performance and pocket the excess by getting you parts that match your systems capabilities.