Write behind caching - disable it for speed - why?

FP wrote on 3/31/2000, 7:31 AM
Many audio sites offer the tip that you should manually
disable write-behind caching on your hard drive to kick up
the speed a bit.

I'm looking for technical opinions on if / why this is a
good idea. I don't really know what write behind caching
does and what the risks of disabling it might be.

Anyone who can shine some light?

thanks!

Paul

Comments

CDM wrote on 3/31/2000, 7:53 AM
I heard that those tips were written before people really knew how to
properly write software for Windows. Sonic's software is optimized
for Windows and understands the operating system. I don't believe any
of these things are necessary...

F. Paul Lembo III wrote:
>>Many audio sites offer the tip that you should manually
>>disable write-behind caching on your hard drive to kick up
>>the speed a bit.
>>
>>I'm looking for technical opinions on if / why this is a
>>good idea. I don't really know what write behind caching
>>does and what the risks of disabling it might be.
>>
>>Anyone who can shine some light?
>>
>>thanks!
>>
>>Paul
Kelly_S wrote on 3/31/2000, 3:25 PM
Hi there.

Charles, you're right.

Vegas is optimized for the standard Windows configurations - changing
the system configuration (such as Write Behind Caching) can actually
hinder the performance as opposed to improving it.



Charles de Montebello wrote:
>>I heard that those tips were written before people really knew how
to
>>properly write software for Windows. Sonic's software is optimized
>>for Windows and understands the operating system. I don't believe
any
>>of these things are necessary...
>>
>>F. Paul Lembo III wrote:
>>>>Many audio sites offer the tip that you should manually
>>>>disable write-behind caching on your hard drive to kick up
>>>>the speed a bit.
>>>>
>>>>I'm looking for technical opinions on if / why this is a
>>>>good idea. I don't really know what write behind caching
>>>>does and what the risks of disabling it might be.
>>>>
>>>>Anyone who can shine some light?
>>>>
>>>>thanks!
>>>>
>>>>Paul
KeithT wrote on 4/6/2000, 1:06 AM
I think many of us are coming to Vegas Pro with our computers
optimized for previous hard disk systems like VST24 and others. This
really changes things for me since I've been using all of the Windows
Optimizing tips and recommendations for VST24. Can you tell us if
any other of these system changes are harmful to us who have switched
to Vegas Pro? I believe many of us use VP in conjunction with other
programs. For example, I still need to use VST24 to record 24
simultaneous tracks from my 3-DA88's thru my Motu 2408 because I
haven't been able to get VP to do it consistently. But perhaps it is
because of my previously mentioned Windows settings. Here is what
many of us have been following:

(taken from www.studio201.com/cwu/)
""Is your Windows 95 / 98 system configured
for optimal performance with Cubase or VST?

Make sure you don't have any compressed drives.

Make sure you are using the "appropriate" filesystem for your drive/s
size (FAT16 vs. FAT32)

Disable Auto Insert Notification for your CD-ROM drive.

Make sure that your MSDOS.SYS file says DoubleBuffer=0

Disable "Windows Animation"

Enable "Show window contents while dragging"

If you have MS Plus, make sure that Low disk space notification is
disabled in the System Agent. Also make sure no other devices run
while your running Cubase.

Disable background tasks and applications.

Fix the size of your vcache.

Disable Read-ahead optimization.

If you have a CD-ROM drive installed which has not got a driver for
Windows 95, it will degrade Windows 95 real-time performance.

Make sure Win95 is not running in compatibility mode.

Defragment your hard drives before each session.

Disable write-behind disk caching.

Set Virtual Memory to a fixed amount.

If you have MS Office, you should disable indexing in the Control
Panel.""

Are any of these detremental to VP? Thanks, Keith


K.Shaffer wrote:
>>Hi there.
>>
>>Charles, you're right.
>>
>>Vegas is optimized for the standard Windows configurations -
changing
>>the system configuration (such as Write Behind Caching) can
actually
>>hinder the performance as opposed to improving it.
>>
>>
>>
>>Charles de Montebello wrote:
>>>>I heard that those tips were written before people really knew
how
>>to
>>>>properly write software for Windows. Sonic's software is
optimized
>>>>for Windows and understands the operating system. I don't believe
>>any
>>>>of these things are necessary...
>>>>
>>>>F. Paul Lembo III wrote:
>>>>>>Many audio sites offer the tip that you should manually
>>>>>>disable write-behind caching on your hard drive to kick up
>>>>>>the speed a bit.
>>>>>>
>>>>>>I'm looking for technical opinions on if / why this is a
>>>>>>good idea. I don't really know what write behind caching
>>>>>>does and what the risks of disabling it might be.
>>>>>>
>>>>>>Anyone who can shine some light?
>>>>>>
>>>>>>thanks!
>>>>>>
>>>>>>Paul
TJ wrote on 4/12/2000, 9:08 PM
I'd say only setting virtual memory to fixed and disable write behind
caching have the potential to hurt performance.

Disabling virtual memory will have the effect of causing memory
allocations fail rather than just cause a performance hit.

In some ways this is good. You don't take a hit at a critical time
and cause gapping in your audio.

BUT Vegas really doesn't every try to allocate memory DURING playback
unless things are really getting behind (i.e. you are already
gapping).

Disabling virtual memory also has the side effect of making
applications (ANY application running at the time) be MUCH more
likely to crash if they contain bugs in their handling of allocation
failures. A lot of applications have this problem since most users
DONT disable virtual memory, and thus few bugs are reported.

I'd say only disable virtual memory if you test it and find that it
actually does seem to help. Otherwise, you are asking for trouble and
getting possibly no benefit at all.

Turning off write behind is a more difficult call. It slows down
overall system performance. Making your system slower doesn't
generally help. HOWEVER, it also makes the performance of the system
more even. Turning this off increases the average time to write
to the disk, but decreases the maximum.

With poorly written software, reducing he maximum matters a lot.
With well written software, it matters less. Possibly not at all.

This can, in some cases, be the difference between occasional
gapping, and just barely getting by without gapping.
It can also CAUSE gapping because it slows the system down overall.

The only way to find out for sure is to try it both ways and look at
the results.

In summary, neither of these changes is an unqualified win. Use them
if they help, leave them at the default settings if they hurt or
don't seem to make any difference.

tj

Keith wrote:
>>I think many of us are coming to Vegas Pro with our computers
>>optimized for previous hard disk systems like VST24 and others.
This
>>really changes things for me since I've been using all of the
Windows
>>Optimizing tips and recommendations for VST24. Can you tell us if
>>any other of these system changes are harmful to us who have
switched
>>to Vegas Pro? I believe many of us use VP in conjunction with
other
>>programs. For example, I still need to use VST24 to record 24
>>simultaneous tracks from my 3-DA88's thru my Motu 2408 because I
>>haven't been able to get VP to do it consistently. But perhaps it
is
>>because of my previously mentioned Windows settings. Here is what
>>many of us have been following:
>>
>>(taken from www.studio201.com/cwu/)
>>""Is your Windows 95 / 98 system configured
>>for optimal performance with Cubase or VST?
>>
>>Make sure you don't have any compressed drives.
>>
>>Make sure you are using the "appropriate" filesystem for your
drive/s
>>size (FAT16 vs. FAT32)
>>
>>Disable Auto Insert Notification for your CD-ROM drive.
>>
>>Make sure that your MSDOS.SYS file says DoubleBuffer=0
>>
>> Disable "Windows Animation"
>>
>>Enable "Show window contents while dragging"
>>
>>If you have MS Plus, make sure that Low disk space notification is
>>disabled in the System Agent. Also make sure no other devices run
>>while your running Cubase.
>>
>>Disable background tasks and applications.
>>
>>Fix the size of your vcache.
>>
>>Disable Read-ahead optimization.
>>
>>If you have a CD-ROM drive installed which has not got a driver for
>>Windows 95, it will degrade Windows 95 real-time performance.
>>
>>Make sure Win95 is not running in compatibility mode.
>>
>>Defragment your hard drives before each session.
>>
>>Disable write-behind disk caching.
>>
>>Set Virtual Memory to a fixed amount.
>>
>>If you have MS Office, you should disable indexing in the Control
>>Panel.""
>>
>>Are any of these detremental to VP? Thanks, Keith
>>
>>
>>K.Shaffer wrote:
>>>>Hi there.
>>>>
>>>>Charles, you're right.
>>>>
>>>>Vegas is optimized for the standard Windows configurations -
>>changing
>>>>the system configuration (such as Write Behind Caching) can
>>actually
>>>>hinder the performance as opposed to improving it.
>>>>
>>>>
>>>>
>>>>Charles de Montebello wrote:
>>>>>>I heard that those tips were written before people really knew
>>how
>>>>to
>>>>>>properly write software for Windows. Sonic's software is
>>optimized
>>>>>>for Windows and understands the operating system. I don't
believe
>>>>any
>>>>>>of these things are necessary...
>>>>>>
>>>>>>F. Paul Lembo III wrote:
>>>>>>>>Many audio sites offer the tip that you should manually
>>>>>>>>disable write-behind caching on your hard drive to kick up
>>>>>>>>the speed a bit.
>>>>>>>>
>>>>>>>>I'm looking for technical opinions on if / why this is a
>>>>>>>>good idea. I don't really know what write behind caching
>>>>>>>>does and what the risks of disabling it might be.
>>>>>>>>
>>>>>>>>Anyone who can shine some light?
>>>>>>>>
>>>>>>>>thanks!
>>>>>>>>
>>>>>>>>Paul
KeithT wrote on 4/13/2000, 1:57 AM
Thank you for your informative answer. Keith

John M. Knoeller wrote:
>>I'd say only setting virtual memory to fixed and disable write
behind
>>caching have the potential to hurt performance.
>>
>>Disabling virtual memory will have the effect of causing memory
>>allocations fail rather than just cause a performance hit.
>>
>>In some ways this is good. You don't take a hit at a critical time
>>and cause gapping in your audio.
>>
>>BUT Vegas really doesn't every try to allocate memory DURING
playback
>>unless things are really getting behind (i.e. you are already
>>gapping).
>>
>>Disabling virtual memory also has the side effect of making
>>applications (ANY application running at the time) be MUCH more
>>likely to crash if they contain bugs in their handling of
allocation
>>failures. A lot of applications have this problem since most users
>>DONT disable virtual memory, and thus few bugs are reported.
>>
>>I'd say only disable virtual memory if you test it and find that it
>>actually does seem to help. Otherwise, you are asking for trouble
and
>>getting possibly no benefit at all.
>>
>>Turning off write behind is a more difficult call. It slows down
>>overall system performance. Making your system slower doesn't
>>generally help. HOWEVER, it also makes the performance of the
system
>>more even. Turning this off increases the average time to write
>>to the disk, but decreases the maximum.
>>
>>With poorly written software, reducing he maximum matters a lot.
>>With well written software, it matters less. Possibly not at all.
>>
>>This can, in some cases, be the difference between occasional
>>gapping, and just barely getting by without gapping.
>>It can also CAUSE gapping because it slows the system down overall.
>>
>>The only way to find out for sure is to try it both ways and look
at
>>the results.
>>
>>In summary, neither of these changes is an unqualified win. Use
them
>>if they help, leave them at the default settings if they hurt or
>>don't seem to make any difference.
>>
>>tj
>>
>>Keith wrote:
>>>>I think many of us are coming to Vegas Pro with our computers
>>>>optimized for previous hard disk systems like VST24 and others.
>>This
>>>>really changes things for me since I've been using all of the
>>Windows
>>>>Optimizing tips and recommendations for VST24. Can you tell us
if
>>>>any other of these system changes are harmful to us who have
>>switched
>>>>to Vegas Pro? I believe many of us use VP in conjunction with
>>other
>>>>programs. For example, I still need to use VST24 to record 24
>>>>simultaneous tracks from my 3-DA88's thru my Motu 2408 because I
>>>>haven't been able to get VP to do it consistently. But perhaps
it
>>is
>>>>because of my previously mentioned Windows settings. Here is
what
>>>>many of us have been following:
>>>>
>>>>(taken from www.studio201.com/cwu/)
>>>>""Is your Windows 95 / 98 system configured
>>>>for optimal performance with Cubase or VST?
>>>>
>>>>Make sure you don't have any compressed drives.
>>>>
>>>>Make sure you are using the "appropriate" filesystem for your
>>drive/s
>>>>size (FAT16 vs. FAT32)
>>>>
>>>>Disable Auto Insert Notification for your CD-ROM drive.
>>>>
>>>>Make sure that your MSDOS.SYS file says DoubleBuffer=0
>>>>
>>>> Disable "Windows Animation"
>>>>
>>>>Enable "Show window contents while dragging"
>>>>
>>>>If you have MS Plus, make sure that Low disk space notification
is
>>>>disabled in the System Agent. Also make sure no other devices run
>>>>while your running Cubase.
>>>>
>>>>Disable background tasks and applications.
>>>>
>>>>Fix the size of your vcache.
>>>>
>>>>Disable Read-ahead optimization.
>>>>
>>>>If you have a CD-ROM drive installed which has not got a driver
for
>>>>Windows 95, it will degrade Windows 95 real-time performance.
>>>>
>>>>Make sure Win95 is not running in compatibility mode.
>>>>
>>>>Defragment your hard drives before each session.
>>>>
>>>>Disable write-behind disk caching.
>>>>
>>>>Set Virtual Memory to a fixed amount.
>>>>
>>>>If you have MS Office, you should disable indexing in the Control
>>>>Panel.""
>>>>
>>>>Are any of these detremental to VP? Thanks, Keith
>>>>
>>>>
>>>>K.Shaffer wrote:
>>>>>>Hi there.
>>>>>>
>>>>>>Charles, you're right.
>>>>>>
>>>>>>Vegas is optimized for the standard Windows configurations -
>>>>changing
>>>>>>the system configuration (such as Write Behind Caching) can
>>>>actually
>>>>>>hinder the performance as opposed to improving it.
>>>>>>
>>>>>>
>>>>>>
>>>>>>Charles de Montebello wrote:
>>>>>>>>I heard that those tips were written before people really
knew
>>>>how
>>>>>>to
>>>>>>>>properly write software for Windows. Sonic's software is
>>>>optimized
>>>>>>>>for Windows and understands the operating system. I don't
>>believe
>>>>>>any
>>>>>>>>of these things are necessary...
>>>>>>>>
>>>>>>>>F. Paul Lembo III wrote:
>>>>>>>>>>Many audio sites offer the tip that you should manually
>>>>>>>>>>disable write-behind caching on your hard drive to kick up
>>>>>>>>>>the speed a bit.
>>>>>>>>>>
>>>>>>>>>>I'm looking for technical opinions on if / why this is a
>>>>>>>>>>good idea. I don't really know what write behind caching
>>>>>>>>>>does and what the risks of disabling it might be.
>>>>>>>>>>
>>>>>>>>>>Anyone who can shine some light?
>>>>>>>>>>
>>>>>>>>>>thanks!
>>>>>>>>>>
>>>>>>>>>>Paul