Intel Core 2 Extreme QX9775
Runs in an LGA 775 board only with the adapter sticker, the socket tabs removed and BIOS support for its core. How the mod works.
Intel Core 2 Extreme QX9775: 4-core, 3.2 GHz, Yorkfield, LGA 771, 1600 MT/s FSB, 12 MB (2 x 6 MB) L2, 150 W TDP.
An odd one: a Core 2 Extreme in the LGA 771 package, made for Intel's dual-socket Skulltrail board (D5400XS). It carries the Harpertown product code 80574 and is closely related to the Xeon X5482, so think of it as a cousin of that Xeon with an Extreme badge. On a desktop board it runs alone, one chip where Skulltrail took two. The 150 W TDP ties for the highest in this database, and the 1600 MT/s bus needs a board that can run it. Tcase is 63.0 °C and VID spans 0.85 V to 1.35 V. Intel's own QX9775 spec update covers its single stepping, C0, as sSpec SLANY with CPUID 10676. It is a showpiece for a strong 45 nm board, not an easy upgrade.
| Family | Core 2 Extreme |
|---|---|
| Codename | Yorkfield |
| Socket | LGA 771 |
| Cores / threads | 4 / 4 |
| Base clock | 3.2 GHz |
| Front-side bus | 1600 MT/s (400 MHz base clock) |
| Multiplier | 8x |
| L2 cache | 12 MB (2 x 6 MB) |
| TDP | 150 W |
| Process | 45 nm |
| Launch | Q1 2008 |
| Dual-socket capable | Yes |
| VT-x | Yes |
| SSE4.1 | Yes |
| Enhanced SpeedStep | Yes |
| Max case temperature | 63 °C |
| Voltage range (VID) | 0.85 V to 1.35 V |
Steppings and microcode IDs
| Stepping | CPUID | sSpec |
|---|---|---|
| C0 | 10676 | SLANY |
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
Closest LGA 775 desktop chip: Core 2 Extreme QX9770 (3.2 GHz, 1600 MT/s, 12 MB (2 x 6 MB)). A board that lists it is the best sign it can run the Core 2 Extreme QX9775.
Fit the adapter sticker, cut the two key tabs out of the LGA 775 socket and add BIOS microcode for CPUID 10676 with the LGA 771 platform ID; the board must already run 45 nm Yorkfield quads, run a 400 MHz bus (or the chip runs slower) and have power delivery meant for 150 W. The tab cut cannot be undone, so back up the current BIOS and work powered off and grounded.
Check a specific board with the LGA 771 to 775 compatibility checker.