Did you ever try and calculate the difference? 1TiB = 1024GiB = 10241024MiB = 102410241024KiB = 1024102410241024 bytes... 1024^4 is 1099511627776 bytes... So

Did you ever try and calculate the difference? 1TiB = 1024GiB = 10241024MiB = 102410241024KiB = 1024102410241024 bytes... 1024^4 is 1099511627776 bytes... So it's 1099 GB vs 1000 GB which is a solid 10% difference. Your TCP overhead is not anywhere close to 10% unless you are sending with an MTU of 240...