AMD Phenom II X2 B55 socket: Socket AM3
The AMD Phenom II X2 B55 uses the Socket AM3 socket. It is an 80 W dual core Callisto desktop part at 3.0 GHz with 6 MB of L3 cache for business towers.
- Socket
- Socket AM3
- Launched
- October 2009
- Cores and threads
- 2 and 2
- Default TDP
- 80 W
- Codename
- Callisto
- Segment
- Desktop
- Family
- AMD Phenom II X2
- Clocks
- 3.0 GHz
AMD Phenom II X2 B55 specifications
| Cores | 2 |
|---|---|
| Threads | 2 |
| Core architecture | Callisto cores on 45 nm |
| Clocks | 3.0 GHz (no turbo) |
| Cache | 1 MB L2 (2 × 512 KB), 6 MB shared L3 |
| Default TDP | 80 W |
| Manufacturing process | 45 nm |
| Memory support | DDR2 and DDR3, 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 Phenom II X2 B55 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 Phenom II X2 B55 is
The AMD Phenom II X2 B55 is a dual core Callisto desktop processor from October 2009 for business systems. It runs two K10 cores at 3.0 GHz with no turbo, so 2 cores give 2 threads. Each core carries 512 KB of L2 cache for 1 MB in total, backed by 6 MB of shared L3 cache. Power is rated at 80 W on a 45 nm process.
The B55 matches the consumer 545 on clocks with business availability. Against the B53 it adds 200 MHz at the same 80 W. The 6 MB L3 cache helps office databases.
There is no graphics on the die. Board video comes from 7 and 8 series chipsets where fitted.
Socket and motherboard compatibility
The Phenom II X2 B55 fits Socket AM3 with 938 pins. All 7 series and 8 series boards boot Callisto directly.
AM3 chips also fit AM3+ boards. It 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 X2 B57 page shows a faster business dual.
Memory, PCIe and cooling
Memory is DDR2 up to PC2-8500 and DDR3 up to PC3-10600 in two channels, with ECC UDIMMs where boards wire them.
HyperTransport links the CPU to the chipset at 2 GHz. PCIe Gen 2 slots hang off the chipset.
Cooling is the stock 80 W class heatsink on the 48 × 96 mm mount.
Upgrade paths
On Socket AM3 the upgrade is the B57 or B59 on the same board. Beyond AM3 a move to AM3+ needs a new board.
Frequently asked questions
What socket does the Phenom II X2 B55 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 Phenom II X2 B55 have?
Two cores and two threads at 3.0 GHz with 512 KB of L2 per core and 6 MB of shared L3 cache.
What memory works with the Phenom II X2 B55?
DDR2 and DDR3 in two channels.
Sources and verification
Facts last checked against these sources on . Page last edited on .