Intel Core 2 Quad Q9400S socket: LGA 775
The Intel Core 2 Quad Q9400S uses the LGA 775 socket. It is a 65 W quad core Yorkfield desktop part at 2.666 GHz with 6 MB of L2 cache for efficient towers.
- Socket
- LGA 775
- Launched
- January 2009
- Cores and threads
- 4 and 4
- Base power
- 65 W
- Codename
- Yorkfield
- Segment
- Desktop
- Family
- Intel Core 2 Quad
- Clocks
- 2.67 GHz
Intel Core 2 Quad Q9400S specifications
| Cores | 4 |
|---|---|
| Threads | 4 |
| Core architecture | Yorkfield cores on 45 nm |
| Clock | 2.666 GHz (no turbo) |
| Front side bus | 1333 MT/s |
| Cache | 6 MB L2 (2 × 3 MB) |
| Thermal design power | 65 W |
| Manufacturing process | 45 nm |
| Memory support | DDR2 or DDR3, two channels (board dependent) |
| PCI Express | PCIe Gen 2 from the board chipset |
| Integrated graphics | None (discrete graphics) |
| Multiplier | Locked |
| Package | LGA775 |
Motherboard and chipset compatibility
Intel Core 2 Quad Q9400S 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 Q9400S is
The Intel Core 2 Quad Q9400S is a quad core Yorkfield desktop processor from January 2009. It runs four cores at 2.666 GHz with no turbo and no Hyper-Threading, so 4 cores give 4 threads. Cache is 6 MB of L2 in two 3 MB dies on a 45 nm process. Power is rated at 65 W with a 1333 MT/s front side bus.
The Q9400S pairs 6 MB of cache with 65 W for efficient towers. Specdle confirms January 2009 with 4 cores, 4 threads and 65 W at $320 launch price. Against the Q8400S it adds cache at the same 65 W.
There is no graphics on the CPU. Display needs a discrete card.
Socket and motherboard compatibility
The Core 2 Quad Q9400S fits LGA 775 with 775 lands. Intel 4 series boards boot Yorkfield natively, while 3 series boards need a listed BIOS.
The Socket vs chipset: what decides whether a CPU works guide covers pairing rules, and the Intel Core 2 Quad Q6600 page shows a Kentsfield quad on the same socket.
Memory, PCIe and cooling
Memory is DDR2 or DDR3 in two channels depending on the board chipset.
The 1333 MT/s front side bus links the CPU to the chipset. PCIe Gen 2 slots hang off the chipset.
Cooling is a 65 W class tower on the 72 × 72 mm pattern.
Upgrade paths
On LGA 775 the upgrade is the Q9505S or Q9550S on the same board. Beyond LGA 775 a move to LGA 1156 needs a new board.
Frequently asked questions
What socket does the Core 2 Quad Q9400S use?
LGA 775, the 775-land package. Intel 4 series boards boot it natively, 3 series after a BIOS update.
How many cores does the Core 2 Quad Q9400S have?
Four cores and four threads at 2.666 GHz with 6 MB of L2 cache in two dies.
What memory works with the Core 2 Quad Q9400S?
DDR2 or DDR3 in two channels depending on the board chipset.
Sources and verification
Facts last checked against these sources on . Page last edited on .