Latency issues

[#1]

Hi, I'm having higher than normal latency on my line and have been for a little while now.  It seems to be currently around the 18 - 20 ms mark whereas it used to be consistently around the 9 - 12 ms mark.  It is having a noticeable effect, particularly when gaming on my PS4.  I've also had a couple of issues with DNS being unreachable for a couple of minutes.  I have Safeguard enabled so are using the Safeguard DNS servers.
I have a SamKnows whitebox on my line and have attached my latency graph for the last 6 months.  Anyone else experiencing issues?  I'm using a Home Hub 5 on my line, and have reset it more than once lately to try and resolve the issue.

[#2]

Pings of 20ms are great, absolutely nothing wrong with them at all and certainly shouldn't be a noticeable ping change.

[#3]

Rubbish.
There's clearly an issue of some sort, and this is a symptom.
Note:

Quote from: notoriousdbp

I've also had a couple of issues with DNS being unreachable for a couple of minutes.

Maybe line quality improved for some months and now worse again? Don't know.
But not nothing. IMHO.
Its one thing to say "We can't be bothered with this;" but it's another to deliberately misrepresent a useful technical observation as a means of not saying that directly.

[#4]

A step-change of 7 or 8 ms is typical of what happens when interleaving is applied or removed in one direction on FTTC, the graph seems to roughly match this typical figure so it's fairly likely that this is what's happened.
I suspect that the DNS issues are quite separate.

[#5]

Thanks for the replies everyone, It may be purely coincidental but I changed my router last Monday and my pings have dropped to consistently being between 11.5 and 12 ms, and I've noticed a significant improvement in online gaming.  For those interested the router I purchased was one of these http://www.maplin.co.uk/p/tp-link-ac750-archer-vr200-vdsladsl-modem-router-a57xu and it works really well. I do wonder if some of the issues could have been with my Home hub 5.