Intel Core 2 Quad Q8400 socket: LGA 775
The Intel Core 2 Quad Q8400 uses the LGA 775 socket. It is a 95 W quad core Yorkfield desktop part at 2.666 GHz with 4 MB of L2 cache.
- Socket
- LGA 775
- Launched
- April 19, 2009
- 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 Q8400 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 | 4 MB L2 (2 × 2 MB) |
| Thermal design power | 95 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 Q8400 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 Q8400 is
The Intel Core 2 Quad Q8400 is a quad core Yorkfield desktop processor that Intel launched on April 19, 2009 at 2.666 GHz. It runs four cores at 2.666 GHz with no turbo and no Hyper-Threading, so 4 cores give 4 threads. Cache is 4 MB of L2 in two 2 MB dies on a 45 nm process with 456 million transistors. Power is rated at 95 W with a 1333 MT/s front side bus and the SLGT6 sSpec.
The Q8400 sits between the Q8300 and Q9400 with 4 MB of cache against 6 MB. CPU-World tables confirm 2.666 GHz with 4 MB and 95 W. Against the Q8400S it matches clocks at higher power for boards with strong delivery.
There is no graphics on the CPU. Display needs a discrete card.
Socket and motherboard compatibility
The Core 2 Quad Q8400 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 tower rated for 95 W on the 72 × 72 mm pattern.
Upgrade paths
On LGA 775 the upgrade is the Q9400 with 6 MB of cache or the Q9550 with 12 MB 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 Q8400 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 Q8400 have?
Four cores and four threads at 2.666 GHz with 4 MB of L2 cache in two dies.
What memory works with the Core 2 Quad Q8400?
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 .