Intel Core 2 Quad Q8400S
Drops into a supported LGA 775 board as it is; check the board's CPU list. How to check.
Intel Core 2 Quad Q8400S: 4-core, 2.66 GHz, Yorkfield, LGA 775, 1333 MT/s FSB, 4 MB (2 x 2 MB) L2, 65 W TDP.
The low-power twin of the Q8400, launched in the same quarter, Q2 2009: same 2.66 GHz, same multiplier of 8 on a 1333 MT/s bus, same 4 MB of L2 in two 2 MB halves. The S suffix means a 65 W TDP and a higher Tcase limit, 76.3 °C. Tcase is a ceiling at the center of the heat spreader, not a forecast of how hot the chip will run, so the higher figure is permission rather than a warning. Its one sSpec, SLGT7, is R0 with CPUID 1067A, and VT-x and SSE4.1 are both present. For a compact build with a small cooler, it keeps the Q8400's clock at a power rating that is easier to handle.
| Family | Core 2 Quad |
|---|---|
| Codename | Yorkfield |
| Socket | LGA 775 |
| Cores / threads | 4 / 4 |
| Base clock | 2.66 GHz |
| Front-side bus | 1333 MT/s (333 MHz base clock) |
| Multiplier | 8x |
| L2 cache | 4 MB (2 x 2 MB) |
| TDP | 65 W |
| Process | 45 nm |
| Launch | Q2 2009 |
| Dual-socket capable | No |
| VT-x | Yes |
| SSE4.1 | Yes |
| Enhanced SpeedStep | Yes |
| Max case temperature | 76.3 °C |
| Voltage range (VID) | 0.85 V to 1.3625 V |
Steppings and microcode IDs
| Stepping | CPUID | sSpec |
|---|---|---|
| R0 | 1067A | SLGT7 |
A BIOS needs a microcode update matching the CPUID (and, for Xeons, the LGA 771 platform ID). See LGA 771 Xeon microcode and how to read your stepping.
Mod notes
Nothing to cut. Check that the board's CPU list names the Q8400S and its R0 stepping, then move to that BIOS version if yours is older, with the current image saved to a file and the power steady while it writes.