CRC events indicate that the data packet has been corrupted, and will need to be re-transmitted, this introduces delay.
If there are a lot of CRC errors, then changing the latency to interleaved, will introduce Forward Error Correction, which allows many errors to be corrected by the home hub, without having to resend the whole packet again.
Interleaving introduces a small overhead, which includes a slight drop in connection speed, and a tiny delay.
Please see how it goes, and report back on this thread. Thanks.
i just done the quiet line test using a cordless phone And i hear no humming just a very feint crackling if that helps
And by feint i mean very feint yet holding a conversation on the phone is clear so could that be the problem