Intel Core 2 Quad Q9550 socket: LGA 775

The Intel Core 2 Quad Q9550 uses the LGA 775 socket. It is a 95 W quad-core Yorkfield desktop part at 2.833 GHz with 12 MB of L2 cache for fast towers.

Socket
LGA 775
Launched
March 2008
Cores and threads
4 and 4
Base power
95 W
Codename
Yorkfield
Segment
Desktop
Clocks
2.83 GHz

Intel Core 2 Quad Q9550 specifications

Cores4
Threads4
Core architectureYorkfield cores on 45 nm
Clocks2.833 GHz (no turbo)
Cache12 MB L2 (2x6 MB)
Processor base power (TDP)95 W
Manufacturing process45 nm
Memory supportDDR2-800 or DDR3-1066 through the board chipset
Front side bus1333 MT/s
PCI ExpressPCIe 2.0 from the board chipset
Integrated graphicsNone (board video where fitted)
MultiplierLocked
PackageLGA 775

Motherboard and chipset compatibility

Intel Core 2 Quad Q9550 needs a motherboard with a LGA 775 socket. The table shows which chipset series accept it.

SeriesChipsetsSupport
Intel 4 seriesX48, P45, G45, G41Works out of the box
Intel 3 seriesX38, P35, G33, G31Needs 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

TypeLGA, 775 contacts
Package size37.5 × 37.5 mm
Introduced2004
MemoryDDR, DDR2 or DDR3, depending on the motherboard chipset
Cooler mounting holes72 × 72 mm

Read the full LGA 775 socket guide

What the Core 2 Quad Q9550 is

The Intel Core 2 Quad Q9550 is a 2.833 GHz fast quad core from March 2008. It runs four Yorkfield cores at 2.833 GHz with no turbo, so 4 cores give 4 threads. Cache is 6 MB of L2 per die, 12 MB total, on a 45 nm process. Power is rated at 95 W on LGA 775.

The Q9550 stepped the 12 MB Yorkfield line up on a 1333 MT/s bus at the March 2008 quad launch, with SSE4.1 over Kentsfield parts. It exists because Intel wanted near-top threaded speed at a mainstream price for buyers who ran encoding and rendering without Extreme pricing.

Socket and motherboard compatibility

The Q9550 drops into LGA 775 boards with DDR2 or DDR3 memory and a BIOS that lists early-2008 Yorkfield quads, such as G33 and P35 boards. It pairs with mainstream 3 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 upgrade is the Intel Core 2 Quad Q9650 at 3.0 GHz within the 12 MB line. The Intel Core 2 Quad Q9450 at 2.667 GHz is the cheaper 12 MB option. 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 Q9550 use?

LGA 775, on DDR2 or DDR3 boards with a quad-aware BIOS.

How many cores does the Core 2 Quad Q9550 have?

Four cores and 4 threads at 2.833 GHz with 6 MB of L2 per die.

What memory works with the Core 2 Quad Q9550?

DDR2-800 or DDR3-1066 through the board chipset in two channels.

Sources and verification

  1. Intel Core 2 Quad Q9550 benchmarks (Geekbench)
  2. Intel Core2 Quad Q9550S, Q9550, Q9650, Q9450 MDDS (Intel)

Facts last checked against these sources on . Page last edited on .