Windows 1394a Bandwidth Limiting Issue / SidSpeed Fix (Windows XP‐Vista)
First, let’s explain a little about what the SidSpeed Fix is. Basically, SidSpeed is a value in your windows registry that regulates the speed of your FireWire bus. It can have a value from 0‐3 (0=S100 speed, 1=S200 speed, 2=S400 speed, and 3=800 speed). If a SidSpeed value larger than 3 is used, then Windows will reject that and use a value of 0 instead, so it’s important to use a value of 0‐3.
Normally, the default value for SidSpeed is 2, which corresponds to a transfer rate of 400 mbps (FireWire 400). This speed is standard for most audio interfaces, including ours. The problem is that there are situations where this value can be lowered to “0” during an OS update and result in choppy and unusable performance for streaming audio. This issue seems to have first been encountered in the SP2 update for Windows XP…
http://support.microsoft.com/kb/885222
…and came back again with the XP SP3 update.
http://support.microsoft.com/kb/955408/en‐us
We’ve also seen incorrect (or no) SidSpeed value set in Windows Vista. So now that you have some background, let’s walk through a fix that should work regardless of what version of Windows you’re using.
Log in as Administrator on your computer (or as a User that has Administrator rights). Click on Start, and then click Run. (Figure A.5)
Figure A.5
This will open the Run command box. In the entry field, type the word regedit (Figure A.6)
Figure A.6
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