Intel Core 2 Quad Q9400 socket: LGA 775
The Intel Core 2 Quad Q9400 uses the LGA 775 socket. It is a 95 W quad-core Yorkfield desktop part at 2.667 GHz with 6 MB of L2 cache for mainstream towers.
- Socket
- LGA 775
- Launched
- August 2008
- Cores and threads
- 4 and 4
- Base power
- 95 W
- Codename
- Yorkfield
- Segment
- Desktop
- Family
- Intel Core 2 Quad
- Clocks
- 2.67 GHz
Intel Core 2 Quad Q9400 specifications
| Cores | 4 |
|---|---|
| Threads | 4 |
| Core architecture | Yorkfield cores on 45 nm |
| Clocks | 2.667 GHz (no turbo) |
| Cache | 6 MB L2 (2x3 MB) |
| Processor base power (TDP) | 95 W |
| Manufacturing process | 45 nm |
| Memory support | DDR2-800 or DDR3-1066 through the board chipset |
| Front side bus | 1333 MT/s |
| PCI Express | PCIe 2.0 from the board chipset |
| Integrated graphics | None (board video where fitted) |
| Multiplier | Locked |
| Package | LGA 775 |
Motherboard and chipset compatibility
Intel Core 2 Quad Q9400 needs a motherboard with a LGA 775 socket. The table shows which chipset series accept it.
| Series | Chipsets | Support |
|---|---|---|
| Intel 4 series | X48, P45, G45, G41 | Works out of the box |
| Intel 3 series | X38, P35, G33, G31 | Needs a BIOS update 45 nm Yorkfield quads boot on 3 series boards that list them, after a BIOS update. |
Board makers publish a CPU support list for every model. Check it for your exact board before buying. Chipset details for LGA 775.
LGA 775 at a glance
| Type | LGA, 775 contacts |
|---|---|
| Package size | 37.5 × 37.5 mm |
| Introduced | 2004 |
| Memory | DDR, DDR2 or DDR3, depending on the motherboard chipset |
| Cooler mounting holes | 72 × 72 mm |
What the Core 2 Quad Q9400 is
The Intel Core 2 Quad Q9400 is a 2.667 GHz mainstream quad core from August 2008. It runs four Yorkfield cores at 2.667 GHz with no turbo, so 4 cores give 4 threads. Cache is 3 MB of L2 per die, 6 MB total, on a 45 nm process. Power is rated at 95 W on LGA 775.
The Q9400 tops the 6 MB Yorkfield-6M desktop line on a 1333 MT/s bus. It exists because Intel stretched the mid-range quad to 2.667 GHz for buyers who wanted near-flagship speed without paying for 12 MB parts.
Socket and motherboard compatibility
The Q9400 drops into LGA 775 boards with DDR2 or DDR3 memory and a BIOS that lists late-2008 Yorkfield quads, such as G41 and P45 boards. It pairs with mainstream 4 series chipsets. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.
Memory, PCIe and cooling
Memory is DDR2-800 or DDR3-1066 through the board chipset in two channels.
A 1333 MT/s front side bus ties the CPU to the chipset. PCIe 2.0 slots hang off the chipset.
Cooling is any 95 W rated LGA 775 heatsink on the 72.5 × 72.5 mm mount, with Enhanced SpeedStep trimming draw at idle.
Upgrade paths
On LGA 775 the Q9400 is the 6 MB ceiling, so the upgrade is the Intel Core 2 Quad Q9450 at 2.667 GHz with 12 MB of cache, or the Intel Core 2 Quad Q9300 at 2.5 GHz for a cheaper 6 MB part. Beyond LGA 775 a move to a newer platform needs a new board and memory.
Frequently asked questions
What socket does the Core 2 Quad Q9400 use?
LGA 775, on DDR2 or DDR3 boards with a quad-aware BIOS.
How many cores does the Core 2 Quad Q9400 have?
Four cores and 4 threads at 2.667 GHz with 3 MB of L2 per die.
What memory works with the Core 2 Quad Q9400?
DDR2-800 or DDR3-1066 through the board chipset in two channels.
Sources and verification
Facts last checked against these sources on . Page last edited on .