Please let's not confuse more units here.

  8Mbps (please capitalize the "M" for "mega" and lowercase the "b" for bits) is 8,000,000 bits per second.
  That translates to about 0.954 MiB/sec (Mebibytes per second, see the "i" and the capital "B"?) which is close enough to 1.

We must keep in mind that there are two disparate things being measured in this thread and by FCC. The FCC is ostensibly measuring advertised signaling rates. Your Gigabit Ethernet signals at 1,000,000,000 bits per second, but can't transfer data that fast. Likewise, my cable ISP signals at 100Mbps down and 5Mbps up (yeah, it's criminal) but download speeds are a different thing.

Download speeds can, and should, be measured in computer-oriented mebibytes per second, rather than bits per second, because you are, after all, transferring files. (And yeah, disk space is often measured in powers of ten...) Your ISP's data cap is undoubtedly measured in gibibytes or tebibytes (even though they call them gigabytes or terabytes, that's what the units mean.)

So when you run speedtest.net or Ookla or whatever, you're measuring the actual throughput that the computer's network interface can squeeze through the narrowest straw in your link to the server. That is necessarily a touch lower than the lowest signaling rate of whatever equipment is in-between. Internet connections are sold by trumpeting signaling rates, but those are NOT download nor upload speeds. Never confuse them, because they are overly-optimistic estimates of your maximum throughput (which is infeasible given most PHY and link-layer frame designs.)