IoPageLockLimit?

[IKu]

how do i access the IoPageLockLimit? i went into regedit, etc, memory management, and it's not listed. i tried to create a DWORD called IoPageLockLimit, but it said it already existed, i searched for it, but i can't seem to find it, where is it?

[andyms18a]

PLEASE NOTE THIS IS ONLY TESTED UNDER WINDOWS NT OPERATING SYSTEMS IE NT4 2K AND XP
If your system is fairly I/O intensive, you may benefit from raising
the I/O Page Lock Limit, which can increase the effective rate at
which data is read from or written to the hard disks.

First, benchmark your common tasks. See how long it takes to load and
save large files, how long it takes to search a database or run a
common program; just do your normal tasks, timing them to record how
fast they are. Then follow these steps:

1. Run Regedt32.exe.
2. Bring up the window HKEY_LOCAL_MACHINE (on the local machine)
3. Select System \CurrentControlSet \Control \SessionManager
\MemoryManagement
4. On the right half of the window, double-click IoPageLockLimit
5. Click the Decimal radio button

This value is the maximum bytes that can be locked for I/O operations.
A value of 0 defaults to 512KB. Raise this value by 512KB increments,
exiting regedt32 and benchmarking your system after each increment.
When an increase does not give you a significant performance boost, go
back and undo the last increment.

Caution: There is a limit to this. I recommend you do not set this
value (in bytes) beyond the number of MB of RAM times 128. That is,
if you have 16 MB RAM, do not set IoPageLockLimit over 2048 bytes; for
32 MB RAM, do not exceed 4096 bytes, and so on.

That's the safe method. You may be adventurous or impatient and want
quick results. If so, try this:

1. Benchmark
2. Calculate your maximum IoPageLockLimit value (MB of RAM times 128)
3. Set IoPageLockLimit to 1/2 this value
4. Benchmark again

If you get little or no improvement, work down by 512 byte decrements
till you note a drop in performance, then go back up 512 bytes. If
you did see an improvement, continue with step 5.

5. Raise IoPageLockLimit to 3/4 maximum
6. Benchmark again

If you get little or no improvement in the third benchmark, work down
in 512 byte decrements. If you do get improvement, work up from 3/4
maximum. And if the first increase from 3/4 shows little improvement,
work down from 3/4.

Unless you don't do much I/O, this should give you a significant boost
in performance.