Futaura, I think I know where I've been getting confused. I thought the 8mb profile was the "cap" which is not in fact the case. When you said you had 9.5mb on a good day and that would mean only 1.5mb more with the speedboost I thought "hang on a second I'm on 6.7mb now so that would be a lot more than 1.5mb". It didn't make sense to me but I think it does now if the following is a correct understanding of the situation?

Given my current sync rate of 6.7mb with 38 line attenuation I'm likely on a 8mb profile (ADSL1 or 2+?). I could potentially have my profile changed to a 24mb one but with an 8mb cap. This would likely result in me getting a sync rate of about 10mb as per this chart which due to the 8mb cap would give me a throughput of about 7mb but about 8.5/9mb with the speedboost enabled.

Essentially in my head I was comparing my current 6.7mb sync rate with the sync rate I'd get on an uncapped 24mb profile whereas you were comparing a capped 24mb profile with an uncapped 24mb profile. Is my thinking right here? If not please point out any errors as this stuff is rather complicated.

Renoir

On your Point 5. Its also possible that like most other LLU suppliers TalkTalk might have adopted the following additional "is your line capable rules":

1. If your speed would not be over 8Mb (well 7Mb ish anyway) they cannot really sell you the speed upgrade. It might get you the higher upload but otherwise you'd get nothing for the extra money.
2. If your line is very long or noisy then ADSL2+ might actually give a worse - or less stable - result than ADSL1 and so again you'd be paying for a service that would only give you and them grief.

Yes, pretty much, I think . I should perhaps not have mentioned my line at all, since this obviously confused matters. Your reading of the graph is correct if you are currently on ADSL1, but I'm pretty sure you are most likely already using ADSL2+. My guess would be that you are on a 24ISNR12 profile (if not 8ISNR12). The obvious way to get more speed (higher sync speed and throughput) on your line is to be switched to a 24ISNR6 profile which is the most aggresive, or if that proves unstable 24ISNR9 may suit your line better. So, what I was meaning was that once you are on an optimal profile, you may find you'll then be able to get 8-9Mbps sync speed, and therefore not a lot of difference if you buy the speed boost (to lift the 8Mbps throughput cap) or not.

Hope I've not confused you further... Regarding the profile abbreviations that I've used above, you can find info about them here: http://www.talktalkmembers.com/forums/showthread.php... - lots of other info there which I think you may find useful.

In reply to a post by Futaura:

Yes, pretty much, I think . I should perhaps not have mentioned my line at all, since this obviously confused matters. Your reading of the graph is correct if you are currently on ADSL1, but I'm pretty sure you are most likely already using ADSL2+. My guess would be that you are on a 24ISNR12 profile (if not 8ISNR12). The obvious way to get more speed (higher sync speed and throughput) on your line is to be switched to a 24ISNR6 profile which is the most aggresive, or if that proves unstable 24ISNR9 may suit your line better. So, what I was meaning was that once you are on an optimal profile, you may find you'll then be able to get 8-9Mbps sync speed, and therefore not a lot of difference if you buy the speed boost (to lift the 8Mbps throughput cap) or not.

I would have thought that If I was on a 24mb profile already that my sync speed would at the very least be higher than 6.7mb which is why I assumed I was most likely on an 8mb profile on either ADSL1 or 2+. If I was on a 24mb profile would I not have a sync speed closer to 8-10mb but with the 8mb cap? I guess what I'm saying is that even with a 12db SNRM I'd expect a higher sync speed than 6.7mb on a 24mb profile. Is my thinking just way off? Can I ask them on talktalkmembers forum what profile and ADSL mode I'm currently on?

This can get awfully complicated to discuss without a direct brain to brain neural link .

If you get 6.7Mbps on 8ISNR12, you'll get 6.7Mbps on 24ISNR12 - the profiles are no different in that respect. The 8Mbps profiles just limit your sync speed to 8Mbps if your line is good enough to sync higher than that if on a 24Mbps profile, IYSWIM. Of course, without the speed boost addon there's no difference throughput wise because of the 8meg cap. On a 24ISNR6 profile you probably might be able to hit 10Mbps. I have done before (my line attenuation is pretty much the same as yours), but my line isn't stable enough to keep at that speed due to various inteference in the evenings. Your line might be better. And yes, the support people on the TT member forums will be able to assist in changing your profile to something more optimal. They'll also be able to tell you what mode your router is connected with.

Also, there are some other tweaks that might be doable from your side - if you have a NTE5 master socket, you can try connecting your router to the test socket, or if you have an old style master socket you can try removing the ring wire. But, that's a whole different topic .

So I understand you correctly lets take the hypothetical situation of a line that's capable of a 15mb sync speed. Would the following be correct:

On an 8mb profile their router would show a 8mb sync speed and they'd get about 7mb in throughput
On a 24mb profile their router would show a 15mb sync speed but their throughput would only be 7mb like above due to the 8mb cap (does the 8mb cap apply to the sync speed or the throughput?)
On a 24mb profile with speedboost enabled their router would show a 15mb sync speed and their throughput would be about 13mb

If the above is correct then I think I understand it all now. Basically what threw me off was the use of your line as an example and my thinking that my current 6.7mb sync speed was due to a profile restriction rather than my line just not being that good.

Hi Renoir,

That is correct you got it. The Cap doesn't cap your sync speed it affects the throughput speed. If you pop along to the members forum we can put you on a 24Mb profile to see what you get also play about with other profiles if needed?

Thanks

In reply to a post by TALKTALK_SUPPORT:

That is correct you got it. The Cap doesn't cap your sync speed it affects the throughput speed. If you pop along to the members forum we can put you on a 24Mb profile to see what you get also play about with other profiles if needed?

Well according to Futaura just putting me on a 24mb profile would not have any benefit but rather that a lower SNRM would provide the benefit to actual throughput while combining that with a 24mb profile would simply allow me to see what speed I could get above 8mb with the speedboost assuming the lower SNRM allows that high a sync speed on my line. Is that not correct?

What part of the talktalk members forum would I need to post in?

Renoir

Yes, you're right, and what you said in your previous post too, as TALKTALK_SUPPORT confirmed - might have missed that you are currently only syncing at 6.7Mb. You may already be on a 24mb profile, of course. For sure, switching to a profile with a lower target SNR will increase your sync speed - fingers crossed stability will remain good.

The "Speed & Web Browsing" section would be the best place to post - create a new thread/topic there. BTW, don't worry... no need to get too technical there - just be sure to include a completed sticky questionnaire in your post and the support staff will do the rest.

In reply to a post by Renoir:

On a 24mb profile their router would show a 15mb sync speed but their throughput would only be 7mb like above due to the 8mb cap (does the 8mb cap apply to the sync speed or the throughput?)

Ah yes, a little caveat... missed your question about the cap. Somebody please correct me if I'm wrong, but my speed tests indicate that the 8Mb cap applies to actual throughput. So, if you sync at around 9Mb for example on a 24Mb profile, you will get more throughput (8Mb) than you would on an 8Mb profile (the sync cap restricting you to 7Mb throughput). I may be wrong about that, but as I say, that's what my speed tests indicate (my fastest speed ever recorded is 8.51Mbps). Perhaps I'm on an uncapped profile which I'm not paying for, in which case sshhhh .