Dell OptiPlex 990 Important Information - New System Board User Guide
Summary
This document provides technical information about system board changes for Dell OptiPlex 790/990 computers. Newer boards ship without heatsink and power supply thermal sensor when BIOS is A11 or higher. Explains compatibility considerations and POST error prevention. Intended for service technicians performing system board replacements or BIOS updates.
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Important Information — Dell Opti Plex 790/990 About Warnings WARNING: A WARNING indicates a potential for property damage, personal injury, or death.
System Board The Dell Opti Plex 790/ 790 computers are now shipped with a new system board without the following components: 1. Heatsink 2. Power supply thermal sensor (Desktop chassis only)
Heatsink Removal The following image displays an earlier version of the system board shipped with the heatsink.
Figure 1. System Board of an earlier version of the system board with the heatsink
All system boards shipped with the following BIOS versions or higher will NOT contain the heatsink. Computer Model BIOS version Opti Plex 790/990 A11
If the BIOS is downgraded to an earlier version than the version listed above, an error message will be displayed.
Regulatory Model: D09M, D05D, D03S, D01U Regulatory Type: D05D001, D03S001, D01U001
Page Summary Contents For Dell OptiPlex 990 Important Information - New System Board User Guide
Manual Details
| Brand | Dell |
|---|---|
| Pages | 3 |
| File Size | 422.74 KB |
| Published | June 29, 2026 |
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Frequently Asked Questions
What components were removed from the new OptiPlex 790/990 system boards?
The updated boards no longer contain the heatsink or, for desktop chassis only, the power supply thermal sensor.
What should I do if my BIOS is outdated before replacing a system board?
You must ensure that the BIOS version is A11 or higher to prevent an 'Alert! Chipset heat sink not detected' error during POST.
Will using the newly updated system boards affect overall performance?
No, the text notes that with the new hardware installed, there should be no impact on the system performance.
Is the power supply thermal sensor removed across all OptiPlex models?
No, the power supply thermal sensor is only described as being removed from the desktop chassis.