AMD Phenom II X4 840T socket: Socket AM3
The AMD Phenom II X4 840T uses the Socket AM3 socket. It is a 95 W quad core Zosma desktop part from 2.9 GHz to 3.2 GHz with Turbo Core and 6 MB of L3 cache.
- Socket
- Socket AM3
- Launched
- September 2010
- Cores and threads
- 4 and 4
- Default TDP
- 95 W
- Codename
- Zosma
- Segment
- Desktop
- Family
- AMD Phenom II X4
- Clocks
- 2.9 / 3.2 GHz
AMD Phenom II X4 840T specifications
| Cores | 4 |
|---|---|
| Threads | 4 |
| Core architecture | Zosma cores on 45 nm |
| Clocks | 2.9 GHz base, 3.2 GHz Turbo Core |
| Cache | 2 MB L2 (4 × 512 KB), 6 MB shared 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 Phenom II X4 840T 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 X4 840T is
The AMD Phenom II X4 840T is a quad core Zosma desktop processor that reached OEM systems in late 2010. It runs four K10 cores at 2.9 GHz base with Turbo Core to 3.2 GHz when half the cores idle, so 4 cores give 4 threads. Each core carries 512 KB of L2 cache for 2 MB in total, backed by 6 MB of shared L3 cache. Power is rated at 95 W on a 45 nm process with Thuban heritage and two cores disabled.
The trailing T marks a Turbo Core part harvested from six core Thuban dies. Against the standard Deneb 840 at 3.2 GHz fixed it matches peak clocks with lower base power and adds turbo for single threaded bursts. Against the 960T Black Edition at 3.0 to 3.4 GHz it trails by 100 to 200 MHz at the same 95 W. Some 840T samples unlock to six cores on boards with core unlocking firmware, but unlocking is board dependent and never guaranteed.
There is no integrated graphics on this die. Board video comes from 7 and 8 series chipsets where fitted.
Socket and motherboard compatibility
The Phenom II X4 840T fits Socket AM3 with 938 pins. Boards need a BIOS that lists the Zosma E0 stepping, which usually means a 2010 or later firmware on 7 and 8 series boards. Check the board CPU list because OEM stepping support varies by vendor.
AM3 chips also fit AM3+ boards. The 840T also boots on AM2+ DDR2 boards after a BIOS update that lists E0. 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 fixed clock Deneb for comparison.
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 840T 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. Turbo bursts stay inside the 95 W envelope on the stock sink with normal airflow.
Upgrade paths
On Socket AM3 the upgrade is the 960T Black Edition for an unlocked multiplier at similar power, or a Thuban six core for rendering. Beyond AM3, DDR3 carries to AM3+ while DDR4 needs a new platform.
Frequently asked questions
What socket does the Phenom II X4 840T use?
Socket AM3, the 938-pin package. Boards need a BIOS that lists the Zosma E0 stepping.
How many cores does the Phenom II X4 840T have?
Four cores and four threads at 2.9 GHz base with Turbo Core to 3.2 GHz, with 512 KB of L2 per core and 6 MB of shared L3 cache.
What memory works with the Phenom II X4 840T?
DDR2 up to DDR2-1066 and DDR3 up to DDR3-1333 in two channels.
Sources and verification
Facts last checked against these sources on . Page last edited on .