The Fujitsu D3644-B is a reliable and versatile industrial-grade ATX motherboard designed for performance, stability, and long-term availability. It’s based on the Intel® C246 chipset, which supports a broad range of Intel Xeon E-21xx and E-22xx processors along with 8th and 9th Gen Intel Core CPUs.
If you’re considering using this motherboard for a homelab, workstation, NAS, or a lightweight server, understanding which Xeon CPUs are compatible (and what you gain with each) is crucial. This post breaks down everything you need to know.
CPU Socket and Chipset Support
The Fujitsu D3644-B supports:
- Socket: LGA1151
- Chipset: Intel® C246 Express
This combination is designed to support:
- Intel Xeon E-2100 series (Coffee Lake)
- Intel Xeon E-2200 series (Coffee Lake Refresh)
- 8th and 9th Gen Intel Core i3/i5/i7/i9
- Intel Pentium and Celeron (LGA1151, supported by BIOS)
Note: To use Xeon E-2200 series, you may need a BIOS update (version R1.6.0 or newer). Refer to Kontron BIOS release notes.
Understanding TDP and Why It Matters
TDP (Thermal Design Power) is the maximum amount of heat a processor is expected to generate under standard workloads. This number helps determine:
- What kind of cooling solution you need
- How much power draw the CPU will demand
The D3644-B supports CPUs with a TDP up to 95W, which covers even the highest-end Xeon E chips like the E-2288G.
For most builds, a tower-style cooler with good airflow is recommended, especially if you use a 95W CPU like the E-2288G.
What Does the “G” Mean in Xeon CPUs?
In the Xeon E series, models with a “G” suffix (e.g., E-2288G) come with integrated graphics, specifically Intel UHD Graphics P630.
- With G: Integrated GPU, useful if you’re not installing a discrete graphics card.
- Without G: No GPU. You must use a dedicated graphics card for display output.
This is critical for remote servers or headless setups. If you want onboard video from the motherboard’s display outputs (like VGA or HDMI), you need a “G” CPU.
Memory Support and Limitations
The Xeon E series CPUs support up to 128 GB of DDR4-2666 ECC or non-ECC unbuffered memory.
- Xeon E-22xx: Max 128 GB
- Xeon E-21xx: Max 64 GB
However, the Fujitsu D3644-B motherboard only supports up to 64 GB officially due to firmware and DIMM slot limitations:
- 4 DIMM slots
- Max 16 GB per slot
- ECC and non-ECC supported (depends on CPU capability)
If you’re building a memory-heavy workload (e.g., for virtual machines), you must plan around the 64 GB ceiling.
Full List of Compatible Xeon E-2200 CPUs
| Model | Cores/Threads | Base/Turbo (GHz) | Cache | TDP | Graphics | ECC |
|---|---|---|---|---|---|---|
| E-2288G | 8/16 | 3.7 / 5.0 | 16 MB | 95W | Yes | Yes |
| E-2278G | 8/16 | 3.4 / 5.0 | 16 MB | 80W | Yes | Yes |
| E-2286G | 6/12 | 4.0 / 4.9 | 12 MB | 95W | Yes | Yes |
| E-2276G | 6/12 | 3.8 / 4.9 | 12 MB | 80W | Yes | Yes |
| E-2246G | 6/12 | 3.6 / 4.8 | 12 MB | 80W | Yes | Yes |
| E-2236 | 6/12 | 3.4 / 4.8 | 12 MB | 80W | No | Yes |
| E-2226G | 6/6 | 3.4 / 4.7 | 12 MB | 80W | Yes | Yes |
| E-2274G | 4/8 | 4.0 / 4.9 | 8 MB | 83W | Yes | Yes |
| E-2244G | 4/8 | 3.8 / 4.8 | 8 MB | 71W | Yes | Yes |
| E-2234 | 4/8 | 3.6 / 4.8 | 8 MB | 71W | No | Yes |
| E-2224G | 4/4 | 3.5 / 4.7 | 8 MB | 71W | Yes | Yes |
| E-2224 | 4/4 | 3.4 / 4.6 | 8 MB | 71W | No | Yes |
Full list: Intel ARK – Xeon E-2200 Series
Full List of Compatible Xeon E-2100 CPUs
| Model | Cores/Threads | Base/Turbo (GHz) | Cache | TDP | Graphics | ECC |
|---|---|---|---|---|---|---|
| E-2186G | 6/12 | 3.8 / 4.7 | 12 MB | 95W | Yes | Yes |
| E-2176G | 6/12 | 3.7 / 4.7 | 12 MB | 80W | Yes | Yes |
| E-2174G | 4/8 | 3.8 / 4.7 | 8 MB | 71W | Yes | Yes |
| E-2146G | 6/12 | 3.5 / 4.5 | 12 MB | 80W | Yes | Yes |
| E-2144G | 4/8 | 3.6 / 4.5 | 8 MB | 71W | Yes | Yes |
| E-2136 | 6/12 | 3.3 / 4.5 | 12 MB | 80W | No | Yes |
| E-2134 | 4/8 | 3.5 / 4.5 | 8 MB | 71W | No | Yes |
| E-2126G | 6/6 | 3.3 / 4.5 | 12 MB | 80W | Yes | Yes |
| E-2124G | 4/4 | 3.4 / 4.5 | 8 MB | 71W | Yes | Yes |
| E-2124 | 4/4 | 3.3 / 4.3 | 8 MB | 71W | No | Yes |
| E-2104G | 4/4 | 3.2 / N/A | 8 MB | 65W | Yes | Yes |
Full list: Intel ARK – Xeon E-2100 Series
Final Recommendations
If you want top performance:
- Xeon E-2288G or E-2278G — highest core count and best turbo
If you want ECC + Integrated Graphics:
- Any G-suffix Xeon model (e.g., E-2246G)
If you’re on a budget:
- E-2136 (no iGPU but solid performance)
If you plan to upgrade memory beyond 64GB:
- Consider a different motherboard; D3644-B is capped at 64 GB
