its odd to the point its plain wrong.
Of course it is possible both the broadcom devices are also not correct, but their estimates are much more realistic.
Plainly speaking, if you were to resync now with that estimated attainable and it was accurate then you would expect to actually get close to that sync speed. The attainable is an estimate of what sync speed you would get if you resynced at that moment.
So the asus syncs 2-3mbit higher but also has a bit lower margin?
One of kitz recent posts gave an estimate on how much the zyxel reports for her line per db of snrm. On a longer line where is less tones available its even lower per db. My billion was estimating an extra 3mbit for 0.5-0.7db of spare snrm above 6db and I reckon that was an "over" estimate.
With a 6db margin given 6db is the target your attainable should be the same or extremely close to your sync speed.
Right now I am synced at 72916 with a 5.9db snrm, the attainable estimated by modem is 72892.
Ok check max's post here with pics.
http://forum.kitz.co.uk/index.php?topic=14822.msg277681#msg277681HE has a 10db margin for just over extra 30mbit attainable, its an interleaved screenshot so the attainable is inflated.
I was going to get more info of mydslwebstats but lost the tab in firefox.