| CPU Model | Cores / Threads | Clock Speed | FSB | L2 Cache | Notes |
|-----------|----------------|-------------|-----|----------|-------|
| Intel Core 2 Quad Q9650 | 4 / 4 | 3.00 GHz | 1333 MHz | 12 MB | Maximum stable upgrade |
| Intel Xeon E5450 (with LGA 771 mod) | 4 / 4 | 3.00 GHz | 1333 MHz | 12 MB | Needs microcode mod & sticker adapter |
| Intel Core 2 Duo E8600 | 2 / 2 | 3.33 GHz | 1333 MHz | 6 MB | Best for single-threaded tasks |
| Intel Core 2 Quad Q6600 | 4 / 4 | 2.40 GHz | 1066 MHz | 8 MB | Common cheap option; runs hot |
Update (2023–2025): Enthusiasts have successfully run Xeon E5450 and E5472 on this board after flashing a modified BIOS that adds Xeon microcodes. Without the mod, the board will beep and fail to POST. The safest route is still the Q9650.
| Problem | Solution |
|---------|----------|
| No POST after CPU upgrade | Clear CMOS (jumper or battery removal). Update to BIOS A12 first. |
| Front panel wiring confusion | Use Dell OptiPlex 790 pinout diagram (Power SW: pins 4 & 6 on header). |
| Fan runs at 100% | Wrong fan header – use CPU_FAN for CPU cooler; SYS_FAN for case fan. |
| GPU not recognized | Disable Secure Boot; force Legacy ROM in BIOS. | dell e93839 ga0402 motherboard specs upd
Crucial Driver Update: For Windows 10 or Linux, Dell does not provide AHCI drivers for XP/Vista-era boards. But modern OSes (Win10, Win11 via workaround, Linux kernel 5.15+) have built-in AHCI support. Enable AHCI in BIOS before installing the OS to avoid blue screens.
Discrete Graphics: Supports discrete PCIe video cards. The board typically includes a standard PCIe x16 slot for upgrade graphics.
Before making any changes, document your current system configuration, including the OS, processor, RAM, and any expansion cards. | CPU Model | Cores / Threads |
The E93839 / GA0402 is a reliable entry-level business motherboard. Its main limitation by modern standards is the restriction to 2nd Generation Intel processors and a maximum RAM limit of 8GB. It remains a serviceable board for basic office tasks, light retro-gaming, or as a home server platform when paired with a dedicated low-profile graphics card.
Disclaimer: Specifications may vary slightly depending on the specific BIOS revision and minor manufacturing changes during the production run. This report is based on the standard configuration for the Dell OptiPlex 390 Desktop. | Problem | Solution | |---------|----------| | No
Note: The "GA0402" is a Dell internal part number variant. This board is primarily known as the Dell 0D28YY (or similar revisions like 0C2KJT) in the OptiPlex 790/990 series. The E93839 is the PCB model number.
