I did not expect a huge difference when I switched from an old Cat5 ethernet cable to this brand new Cat6a cable. But I got a very large difference. I switched back and forth several times because it was a little bit hard to believe. I used speedtest.net for my unscientific testing. The major difference was in the download speed. I went from 191.10 Mbps to 348.75 Mbps. Don't tell Time Warner because I'm supposed to be capped at 300 Mbps. I switched cables and repeated the test several times until I just had to accept that the speed was an 82.50% increase. I did read on cableinstall.com that "Cat 6a, while also being 23 gauge, is considerably thicker then Cat 6, which in turn is considerably thicker then Cat 5. Partly, this is due to the extra-thick plastic around the wires themselves, and partly due to the tighter winding of the pairs themselves, creating more copper per inch. Cat 6a will do 10 Gigabit per second networking for the full distance of Ethernet (328 ft.) Cat 6a also reduces the crosstalk among the pairs, which further reduces the delay in the cables." So basically, Cat 6a will do 10G networks further than Cat 6. It has less crosstalk which reduces delay. I am not specifically trying to run a 1000T network or a 10G network. Theoretically, then there is no reason to use Cat6a. I'm just moving data 15 feet from a router to a MacBook Pro. And I am very happy with how fast my data moves. The speed improvement is not just measurable, it is experiential. When I download a file, it blazes. Even my uploads go faster. Where I used to be lucky to upload at 3Mbps, now it is not unusual to upload at 16+ Mbps. It's not the 23 Mbps that speed test says I'm getting, but when times go down by multiples of 5, you notice. This was purely an experimental purchase to see if it would make even the slightest difference. It's not scientific because I did not compare to a brand new Cat 5 cable but to a decade old Cat 5 cable. Could be the older cable had issues. It would be interesting to test the old cable, but time is limited. And to think that 6 months ago I was trying to work on the other side of the house using wifi! That was real speed torture even at 50 to 100 Mbps because of the interference. Also, when you work with uploading and downloading files, the timings make a difference. It's not just about loading web pages.