Windows Vista/W7 - workaround for problems with download speed by MS

Discussion in 'ESET Smart Security' started by Marcos, Jan 20, 2011.

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  1. Marcos

    Marcos Eset Staff Account

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    If you use Windows Vista SP1/2, Windows 7 or Windows 2008 and experience problems with fluctuating download speed, significant speed slowdowns, delayed TCP ACK sending resulting in the remote part not sending data or re-sending the same date repeatedly after installing ESET Smart Security, Microsoft acknowledged a bug in the TCP/IP Stack's ACKing logic that can be worked around by setting the registry value TcpAckFrequency to 1 (for complete instructions, read here).
     
  2. rockshox

    rockshox Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    Why does that KB article refer to XP/2003 and have a date from 2007 on it? Maybe I missed it but I'm not seeing anything related to Windows 7 and 2008?
     
  3. funkydude

    funkydude Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    Probably because by default the registry entry doesn't exist in 7/2008. Here's a tool that does it for you automatically. Used it for years.
     
  4. dmaasland

    dmaasland Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    Should everyone with a Windows 7 / ESS combo use this fix? Or is this problem only present on certain configurations?
     
  5. Marcos

    Marcos Eset Staff Account

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    Re: MS suggests workaround for problems with 1 GB networks

    A quote by a MS engineer on the MSDN forum: We've had a root cause of this issue -- The TCP/IP Stack's ACKing logic has a bug when data segments are taken out of and re-injected back to the same flow at a certain ratio. The bug is easier to manifest when the incoming data rate is very high.
     
  6. kncowans

    kncowans Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    Hello

    Does anybody know if this bug is fixed in Windows 7 Service Pack 1?

    Thanks in advance

    Kevin
     
  7. dmaasland

    dmaasland Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    Probably not. SP1 is (very close to) RTM status so I imagine this one will be a seperate bugfix.

    Thanks Marcos, I'll apply this fix as a precaution.

    EDIT: KB Article about this was created: http://kb.eset.com/esetkb/index?page=content&id=SOLN2654

    EDIT2: Perhaps a coincidence, but:

    * Before applying fix, download speed was around 117 Mbit (Connection max is 120)
    * After applying fix and rebooting, download speed was around 90 Mbit.
    * After removing fix and rebooting, download speed was 120 Mbit again.

    Can someone with a fast connection confirm or deny this?
     
    Last edited: Jan 22, 2011
  8. stackz

    stackz Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    * with fix : 16.5 Mbps
    * no fix : 23.6 Mbps

    Repeated with very similar results.
     
  9. burnard

    burnard Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    This reg fix means your PC will respond to every pack, rather than every 2 or 4 as it would normally. So you are increasing the overhead by responding to every packet. This means that your download speed will be slightly lower, but latency and response are better.
     
  10. terradon

    terradon Registered Member

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    Re: MS suggests workaround for problems with 1 GB networks

    Thanks funkydude,
    That little vbs took away any guesswork.
     
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