Network Buffer Size


Honorable Member
Hi guys
I am experiencing a slow broadband speed and a diagnostic test says the following:-

"The theoretical network limit is 41.31 Mbps The NDT server has a 84.0 KByte buffer which limits the throughput to 5.02 Mbps Your PC/Workstation has a 63.0 KByte buffer which limits the throughput to 1.90 Mbps The network based flow control limits the throughput to 1.94 Mbps"

Can anyone please tell me what to do about this


Windows Forum Admin
Staff member
Premium Supporter

Do you have a VirginMedia connection by any chance? They're rolling out upgrades at the moment. If on Virgin give them a call and they'll run some tests on the connection and reset the modem if necessary.

Just out of interest what are you using for diagnostics?


Honorable Member
Not virgin.
I am with Zen on a BT phone line

cant remember the diagnostics website.
can you recommend one please


Honorable Member
upload speed 0.35 Mbs
Download speed 1.9Mbs

possible speed 8 Mbs
usual speed was 7Mbs plus or minus 500kbs

This website is not affiliated, owned, or endorsed by Microsoft Corporation. It is a member of the Microsoft Partner Program.