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ApdxBAdvanced

Appendix B - Advanced Optimisations

Following advanced options are available:

1. Setting 'Lock Pages in Memory' privilege

cPlay uses Address Windowing Extensions (AWE) to allocate RAM to music files during playback. To enable this, the Lock Pages in Memory privilege has to be set as described here. It is advisable not to make this change until after the system is known to be stable.

cPlay diagnostics show whether AWE has successfully allocated the RAM; Process Explorer or Task Manager will show only a reduction in Available RAM. If Windows does not allocate enough RAM to hold the music to be played, cPlay reverts to standard memory management. (Adding more RAM will cure this. AWE should allow up to four GB to be added though this has not been tested.)

Instructions

2. Replacing winlogon with minlogon

As the name implies, Winlogon.exe is the routine that manages XP user logons. This optimisation involves replacing it with minlogon, its counterpart in XP-Embedded, a ‘stripped down’ XP designed for industrial devices. When done, XP runs with one, and only one, user called ‘.Default’.

The change works well with cMP² – overheads are reduced, there is no logon prompt, boot time is reduced and sound quality improves considerably. However, it can be tricky to implement and should only be performed as the very last stage of optimisation when the system is known to be stable.

1. Errors in carrying out the procedure can make Windows inoperable. It is strongly recommended that an image file of the system partition is made before attempting to implement the change (and that the user knows how to restore the system);
2. Some XP functionality becomes unavailable when using minlogon but the change is reversible for maintenance purposes;
3. As XP is running under a new user, changes made to user settings (Desktop, etc) are lost and need to be repeated. In practice, it is worth re-checking all the XP optimisations.

Step 1 – Obtain minlogon

On a different computer:

1. Download XP Embedded SP2 Feature Pack 2007 (132 MB iso file);
2. Launch Daemon Tools. To mount the iso file, first select a drive letter then the iso file;
3. ‘XP SP2 install’ should launch itself. If so, select Browse CD; if not, use Explorer;
4. Launch 7-Zip. Go to Open Archive and open XPEFP2007.exe;
5. Locate minlogon.exe in the ‘rep’ folder and copy it to a working folder.

Step 2 – Disable Windows File Protection

An XP feature called Windows File Protection (WFP) prevents winlogon being changed or removed – XP simply restores the original file on bootup. Generally, this is a worthwhile security feature but not in this context: WFP has to be disabled. This is not a trivial operation but an easy way is to use XPLite, a shareware utility which lowers XP’s installed footprint. It includes a routine that automatically performs the procedure described below. On the target computer, install XPLite, launch it, select the Windows File Protection tab, click Disabled and Apply.

The manual procedure is described here.

Step 3 – Install minlogon

On the target computer:

1. Ensure that an image file of the system partition has been created and tested;
2. Go to C:\Windows\System32 and rename winlogon.exe to winlogon.exe.bak (Windows issues a warning prompt: Hit Cancel and continue. Make sure that the file isn’t replaced by WFP (check file sizes to confirm)! If you are unable to do this then you must disable WFP);
3. Copy minlogon.exe to C:\Windows\System32. Rename it winlogon.exe (Cancel prompt and check if correct file is used);
4. Using Notepad, create a file called minlogon.reg containing the following text:
   
   
   Windows Registry Editor Version 5.00
   
   [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
   "Config"=dword:00000017
   
   
5. Double-click on minlogon.reg to make the requisite Registry change
6. Reboot. XP should boot to the system account (the ‘.default’ user). The first boot takes longer than usual. There will be no logon prompt. Test.
7. To reverse the change, rename winlogon.exe to winlogon.min and winlogon.bak to winlogon.exe and reboot.
8. Keep backup copies of the two logon files.

Notes:

• Be sure to copy file names correctly - pay particular attention to the file extension as often making a mistake here causes failure.
• There will be no logon prompt on boot. On re-boot, display (and other) settings must be redone as the system defualt logon is used. It's a good idea to re-check all optimisations.
• An easier approach (and preferred by many) has been developed by a cMP² owner and can be found here.

3. ATX PSU Enhancements

All ATX PSUs can be enhanced only after a low power setup is achieved, i.e. a fully specified cMP².

• Adjust 12V Potentiometer. Both Antec EarthWatts and Zalman HP models have a voltage pot to adjust its 12V output. Manufacturers increase 12V output to compensate for voltage drop under load (this is not needed for cMP²). Remove seal and adjust pot counter-clockwise to lower 12V output. It's recommended to keep 12V output within ATX 2.2 specification range: 12V ±5% (11.4 to 12.6). Be sure to only adjust when all power is disconnected.
• Remove all PSU fans. These are noisy and can affect power quality. It's very important to not only disconnect the fans but physically remove them to allow for sufficient passive cooling. Make sure your case allows for this. A system built using SSDs and without any fans is completely quiet. Zalman HP models have heat pipe cooling which offers added passive cooling.
• Add smoothing capacitors on P4 and P24 power rails (alternate approach).

4. Linear Power Supply (P4 & replacement of GD PSUs)

Advanced users have developed power supply improvements replacing standard 5V & 12V lines as used in the P4 connector and Granite Digital Power supplies.

5. Hybrid Power Supply (P24)

Improving power supply on the main mobo supply (P24) is much more difficult. Instead the 12V pico PSU is used with its base supply being a linear 12V supply. DC-DC conversion is done by the pico PCB and suffers some ripple noise. A full computer linear power supply is yet to be built for consumer use.

An elegant and simple way to better P24 power supply

6. Pure Linear Power Supply (P4, P24 & Soundcard)

Ultimate power supply performance is achieved using linear power supplies. Detailed instructions using multiple toroidal transformers can be found in the pdf document. Power to P24, P4 and Juli@ soundcard is explained.

• PDF instructions: Linear PSU.pdf (3,315,300 bytes, downloaded 127 times)
• Discussion

7. Juli@ Soundcard Modifications

Juli@ remains possibly the greatest value for money soundcard. Apart from removing the Analogue PCB for pure Digital output (which you would want if you have an external DAC), here's some excellent innovations from many contributors:

1. Providing cleaner power (picture @10pin header)
2. Direct power supply to PCB (bypassing mobo supply)
3. Clean approach to BNC connectivity
4. External clocking using Juli@'s SPDIF input (critical when not using a dedicated optimised computer)
5. I2S connectivity (connections @10pin & @20pin headers) option (of course you'll need an I2S capable DAC)
6. Advanced analogue & digital PCB modifications (pictures)
7. Replace XO using LClock XO 3 (detailed installation instructions)