Ran across something very odd today. Just had a symmetrical 100 Mb circuit installed at a site I’m contracting at.
When the NIC is set for auto negotiate for duplex and speed, we only get ~96 Mb down and ~45 Mb up. Same scenario if I set the NIC manually to duplex full and 1000. But if I set the NIC manually to duplex full at 100, we get the expected speeds of ~96 down ~96 up.
All cables are Cat6 and I tested this on a Mac, two windows machines, and a Cisco router. All behave the same with regards to the speeds. All tests were done directly connected to the edge switch.
I’m quite baffled. Not that it’s an issue, but why would 100 be faster than 1000? What would be the cause of this?