Intel Core 2 Extreme QX6850 socket: LGA 775
The Intel Core 2 Extreme QX6850 uses the LGA 775 socket. It is a 130 W unlocked quad-core Kentsfield desktop part at 3 GHz with 8 MB of L2 cache for enthusiast towers.
- Socket
- LGA 775
- Launched
- July 2007
- Cores and threads
- 4 and 4
- Base power
- 130 W
- Codename
- Kentsfield
- Segment
- Desktop
- Family
- Intel Core 2 Extreme
- Clocks
- 3.0 GHz
Intel Core 2 Extreme QX6850 specifications
| Cores | 4 |
|---|---|
| Threads | 4 |
| Core architecture | Kentsfield XE cores on 65 nm |
| Clocks | 3 GHz (no turbo) |
| Cache | 8 MB L2 (2x4 MB) |
| Processor base power (TDP) | 130 W |
| Manufacturing process | 65 nm |
| Memory support | DDR2 through the board chipset |
| Front side bus | 1333 MT/s |
| PCI Express | PCIe from the board chipset |
| Integrated graphics | None (board video where fitted) |
| Multiplier | Unlocked |
| Package | LGA 775 |
Motherboard and chipset compatibility
Intel Core 2 Extreme QX6850 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 | Works out of the box |
| Intel 965 and 975X | 975X, P965, G965, Q965 | Needs a BIOS update Works only on boards whose BIOS and voltage regulator were designed for it. Check the board maker's CPU support list. |
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 Extreme QX6850 is
The Intel Core 2 Extreme QX6850 is a 3 GHz unlocked desktop quad core from July 2007. It runs four Core cores at 3 GHz with no turbo, so 4 cores give 4 threads. Cache is 8 MB of L2 as two 4 MB dies on a 65 nm process. Power is rated at 130 W on LGA 775.
The QX6850 moved Kentsfield XE to a 1333 MT/s bus in G0 stepping with a 9x unlocked multiplier at about 999 dollars launch price. It exists because enthusiasts wanted a 3 GHz unlocked quad with faster bus speed than the 1066 MT/s QX6800.
Socket and motherboard compatibility
The QX6850 drops into LGA 775 enthusiast boards with DDR2 memory and a BIOS that lists mid 2007 Extreme quads on 1333 MT/s, such as P35 and X38 boards. Boards need voltage regulator support for the 130 W envelope. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.
Memory, PCIe and cooling
Memory is DDR2 through the board chipset in two channels.
A 1333 MT/s front side bus ties the CPU to the chipset. PCIe slots hang off the chipset.
Cooling is a 130 W rated LGA 775 tower or high-end heatsink on the 72 mm mount, with Enhanced SpeedStep trimming draw at idle.
Upgrade paths
On LGA 775 the upgrade is the Intel Core 2 Extreme QX9650 at 3 GHz on 45 nm with 12 MB of cache, or the Intel Core 2 Extreme QX6800 at 2.933 GHz for a lower bus speed Extreme. The Intel Core 2 Quad Q6700 at 2.667 GHz drops to a locked multiplier. Beyond LGA 775 a move to a newer platform needs a new board and memory.
Frequently asked questions
What socket does the Core 2 Extreme QX6850 use?
LGA 775, on enthusiast DDR2 boards with 1333 MT/s Extreme support.
How many cores does the Core 2 Extreme QX6850 have?
Four cores and 4 threads at 3 GHz with 8 MB of L2 cache and an unlocked multiplier.
What memory works with the Core 2 Extreme QX6850?
DDR2 through the board chipset in two channels.
Sources and verification
Facts last checked against these sources on . Page last edited on .