PSN, Windows Update and other slow downloads. Time to change ISP?

[#1]

What has happened to the speeds of download on the PSN etc. since Christmas? On broadband speed tests i'm getting around 4.6 Mbps, but on Windows updates, PSN downloads etc. I'm lucky if i get 1Mb in 6-10 seconds.
I'm on BBMW option2 and before Christmas as was getting around 1Mbps at peak times on Downloads from PSN etc.  What's happened?  Why doesn't Plusnet provide speed test for different types of traffic? so we can compare to the unthrottled test they make everyone use, that makes them think they are getting faster downloads than they actually are. 
I'm really getting fed up having to wait many minutes to download small updates etc.
Plusnet is starting to get bad write up's in magazines for their traffic management (see this months pc pro magazine)
Hope you do something soon

[#2]

Hi there,
I've certainly not seen the write up in this months PC Pro magasine, but if you have an online copy of the article you're referring to, I'd definitely be interested in see it.
We do, as you quite rightly suggest, limit speeds that are being served across the PSN.  That's because it's served by Limelight Networks which represents a massively large amount of traffic.  It's treated as "download server" as per these pages:
http://www.plus.net/support/broadband/quality_broadband/speed.shtml
What sort of speeds are you seeing?  Yours is the first PSN complaint I've seen for some time.

[#3]

If srwatt is talking about the July issue, that item doesn't seem to be on line, but it would be nice to know which issue?

[#4]

Hi, yes i'm talking about the July issue and i can't find an online article.
In regards to my download speeds the PS3 does not show the speed in Mbps, but watching the downloads in normally takes 5-10 second to download 1 MB.  Last night I downloaded the infamous demo which was about 1230MB and it to the good part of 2 hours.  Before christmas this would have downloaded in under 1 Hour and the same with PS3 firmware updates, they used to take around 5 mins for 120MB now thay take 20-30 mins. When was the throttling changed/enforced for the PSN?