24p Works on Intel Sandy Bridge With UAC Enabled

Last week we posted an update on the need to disable User Account Control (UAC) on Intel’s second generation HD Graphics IPG (Sandy Bridge) systems, but we still weren’t sure how to reliably reproduce the results.  Well a new DH67BL showed up today along with instructions on how to enable the feature on existing hardware which explains why we couldn’t nail it down before.

First let’s take a look at what the DH67BL produced with UAC enabled.  Clearly we’re still not seeing a perfect 23.976Hz, but we are getting refresh rate precision consistent with what was only possible with the security feature disabled when the platform launched back in January.  There is some initial drift, but unlike our previous results it was in the range of 23.970-23.978 settling quickly in the 23.972-23.973 range.

Turning our attention to the same DH67CF board used before, we now get much better precision in line with what we see with the DH67BL. The difference?  Intel helped us out on that; it comes down to how the BIOS gets updated.

Those familiar with Intel motherboards know that there are three main methods for updating the BIOS – EXE, F7 and Recovery.  Having been burned in the past running BIOS updates from Windows (the EXE method) on other vendor’s systems, the F7 (press the F7 key during POST) approach is generally preferable, but for some reason the Recovery method is required in this case for everything to take.

There are a few different ways to do it outlined here, but since they are essentially variations on the same set of actions just the USB (how the DH67CF was updated) is listed below:

1. Copy the recovery file (*.bio) to a bootable FAT formatted* USB thumb drive.
2. Place the thumb drive in a USB port of the target system.
3. Shut down the system and unplug AC power.
4. Open the chassis and remove the BIOS Configuration Jumper. See the Technical Product Specification for details including the location of this jumper.
5. Power the system on.
6. Wait 2-5 minutes for the update to complete.
7. System will either turn off when the recovery process is completed or it will prompt you to turn off the system.
8. Remove the thumb drive from the USB port.
9. Replace the BIOS Configuration Jumper.
10. Restart system.

* Intel notes “bootable”, but when the DH67CF was updated that did not work so the BIO file was copied to a drive just formatted as FAT (i.e. not FAT32 or NTFS – although they may have worked) and it updated properly.

Let us know in the comments if this worked for you.