As you say its possible that different types of noise affect differently. Its a shame that noone could get the dsl_phy from the zyxels f/w to work on the HG612.
I dont see anything in my SNRm to indicate why I get that peak bitswap without fail each day, but I suppose its possible that theres something local to me which only affects a couple of tones to bitswap out and thereby insufficient to affect the overall SNRm average. It is strange that it wasnt there on the HG612.. but then again the HG612 was constantly bitswapping so probably did a total of more swaps over the course of the day.
Aside from the improved SNRm... the bitswap pattern is the only difference I see.
The broadcoms have always worked pretty well on this line.. and I get quite a lot more errors with a lantiq.. plus the SNRm tends to move a bit more.
When I was testing the TPlink I discovered a bug on something and they sent me a tool which real time monitors the SNR in a graphical format so you see SNR shifting constantly. It was quite interesting to note how much movement I constantly had in the evenings at around tone 250. Which co-incidentally is where for a loooong time where Ive always maintained was crosstalk from adsl lines. Since weve been able to see QLN graphs, sure enough theres the typical what I call the inverted shallow bowl that centers around my tone 225 which often identifies cross talk.
So whether most of the 'noise' that effects this line is crosstalk and not much from elsewhere.. who knows.