AMD Athlon II X4 645 socket: Socket AM3
The AMD Athlon II X4 645 uses the Socket AM3 socket. It is a 95 W quad core Propus desktop part at 3.1 GHz with no L3 cache.
- Socket
- Socket AM3
- Launched
- September 2010
- Cores and threads
- 4 and 4
- Default TDP
- 95 W
- Codename
- Propus
- Segment
- Desktop
- Family
- AMD Athlon II X4
- Clocks
- 3.1 GHz
AMD Athlon II X4 645 specifications
| Cores | 4 |
|---|---|
| Threads | 4 |
| Core architecture | Propus cores on 45 nm |
| Clocks | 3.1 GHz (no turbo) |
| Cache | 2 MB L2 (4 × 512 KB), no L3 |
| Default TDP | 95 W |
| Manufacturing process | 45 nm |
| Memory support | DDR2-1066 and DDR3-1333, two channels |
| PCI Express | PCIe 2.0 from the board chipset |
| Integrated graphics | None (board video where fitted) |
| Multiplier | Locked |
| Package | Socket AM3 (µPGA, 938 pins) |
Motherboard and chipset compatibility
AMD Athlon II X4 645 needs a motherboard with a Socket AM3 socket. The table shows which chipset series accept it.
| Series | Chipsets | Support |
|---|---|---|
| 7 and 8 series | 7-Series, 8-Series | Works out of the box |
Board makers publish a CPU support list for every model. Check it for your exact board before buying. Chipset details for Socket AM3.
Socket AM3 at a glance
| Type | PGA, 941 contacts |
|---|---|
| Package size | 40 × 40 mm |
| Introduced | February 2009 |
| Memory | DDR2 up to PC2-8500 and DDR3 up to PC3-10600 |
| Cooler mounting holes | 48 × 96 mm |
What the Athlon II X4 645 is
The AMD Athlon II X4 645 is a quad core Propus desktop processor that AMD released in September 2010. It runs four K10 cores at 3.1 GHz with no turbo, so 4 cores give 4 threads. Each core carries 512 KB of L2 cache for 2 MB in total, and there is no L3 cache. Power is rated at 95 W on a 45 nm process.
The 645 is the fastest standard Propus quad in this batch, 100 MHz above the 640. At 3.1 GHz it closes the gap to Phenom II quads in office and encoding work, though the missing L3 cache still shows in games. It was a common choice for budget towers where a discrete graphics card covers 3D.
There is no integrated graphics on this die. Board video comes from 7 and 8 series chipsets where fitted.
Socket and motherboard compatibility
The Athlon II X4 645 fits Socket AM3 with 938 pins. All 7 series and 8 series boards boot Propus directly.
AM3 chips also fit AM3+ boards. The 645 also boots on AM2+ DDR2 boards after a BIOS update. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules, and the AMD Phenom II X4 975 BE page shows a Phenom II quad with L3 cache.
Memory, PCIe and cooling
Memory support is DDR2 up to PC2-8500 and DDR3 up to PC3-10600 in two channels. A 2 by 2 GB DDR3-1333 kit suits most 645 towers.
HyperTransport 3.0 links the CPU to the chipset at 2.0 GHz. PCIe Gen 2 slots hang off the chipset.
Cooling is the stock 95 W heatsink on the 48 × 96 mm mount.
Upgrade paths
On Socket AM3 the upgrade is a Phenom II X4 with 6 MB of L3 cache, such as the 965 Black Edition at 3.4 GHz and 125 W. Beyond AM3, DDR3 carries to AM3+ while DDR4 needs a new platform.
Frequently asked questions
What socket does the Athlon II X4 645 use?
Socket AM3, the 938-pin package. It also boots on AM2+ DDR2 boards after a BIOS update and on AM3+ boards.
How many cores does the Athlon II X4 645 have?
Four cores and four threads at 3.1 GHz with 512 KB of L2 per core and no L3 cache.
What memory works with the Athlon II X4 645?
DDR2 up to DDR2-1066 and DDR3 up to DDR3-1333 in two channels.
Sources and verification
- List of AMD Athlon II processors (Wikipedia)
- AMD Athlon II X4 645 Specs (TechPowerUp)
- Socket AM3 (Wikipedia)
Facts last checked against these sources on . Page last edited on .