AMD Phenom II X4 840

AMD Phenom II X4 840

AMD Phenom II X4 840: An Overview of an Obsolete Quad-Core in 2025

Relevance, Capabilities, and Practical Advice for Enthusiasts and Budget Builds


Key Specifications: Propus Architecture and Modest Potential

The AMD Phenom II X4 840 processor, released in 2011, is based on the K10.5 microarchitecture (codename Propus). It is a 45nm chip with four physical cores, lacking support for multithreading (4 cores / 4 threads). Its base clock speed is 3.2 GHz without a turbo mode, and its TDP is 95 watts.

Key Features:

- No Integrated Graphics — The integrated GPU is only available on motherboards with chipsets that support this feature (e.g., AMD 880G). The processor itself does not have graphics.

- Cache: L2 — 512 KB per core, L3 — absent.

- Performance: In the Geekbench 6 (2025) benchmark, it scores 357 points in single-threaded and 1024 points in multi-threaded modes. In comparison, the modern budget Ryzen 3 5300G shows around 1500/4500 points.

The Propus architecture is optimized for multi-threaded tasks but falls behind even the early Intel Core i5 second-generation (Sandy Bridge) processors due to weak IPC (instructions per cycle).


Compatible Motherboards: A Hunt for Rarities

The Phenom II X4 840 uses the AM3 socket. Suitable chipsets include:

- AMD 880G, 785G, 970 — support overclocking (with multipliers) and integrated graphics (in 880G).

- Nvidia nForce 700a — rare boards for enthusiasts.

Choosing Features in 2025:

- No New Boards — Only the used market is available. Prices for used models start at $15 (e.g., ASUS M4A88T-M).

- Check BIOS Support — Some boards require a firmware update to work with Phenom II.

- SATA II and USB 2.0 — limitations on the speed of storage and peripherals.


Supported Memory: Only DDR3

The processor works with DDR3 (up to 1333 MHz officially). Real tests show stability with modules up to 1600 MHz when overclocked.

- Maximum Capacity: 16-32 GB (depending on the motherboard).

- DDR4/DDR5 Not Supported — this is a key limitation for upgrades.

Practical Example:

A combination of Phenom II X4 840 + 16 GB DDR3 1600 MHz + SATA SSD provides acceptable speed for office tasks, but does not eliminate latency in rendering or modern games.


Power Supply Recommendations

With a TDP of 95 watts and no integrated graphics, the minimum power supply requirement depends on the graphics card:

- Integrated Graphics (via chipset): A 300W power supply is sufficient (e.g., EVGA 300 W).

- Discrete Graphics Card like GTX 1650: A 450W power supply (Corsair CX450).

- Powerful GPUs (e.g., RTX 3060): Not recommended — the processor will become a "bottleneck."

Important: Use a power supply with an 80+ Bronze certification or higher. Cheap power supplies may operate unstably under load.


Pros and Cons of the Phenom II X4 840

Pros:

- Cost: A used processor can be found for $10-$20.

- Four Cores — suitable for basic multitasking (browsing, office tasks, older games).

- Compatibility with inexpensive DDR3.

Cons:

- Obsolete Architecture — no support for AVX, AES, or other modern instructions.

- High Power Consumption — 95 watts compared to 35-65 watts for modern equivalents.

- No PCIe 3.0/4.0 — limiting the speed of graphics cards and NVMe.


Usage Scenarios: Where is it Still Relevant?

1. Office PC: Working with documents, browsing, Zoom.

2. Media Center: Playback of Full HD video through VLC or Kodi (with GPU).

3. Retro Gaming: Games from the 2010s (e.g., GTA V on low settings).

4. Entry-Level Server: NAS or home file hosting.

Example: A user assembled a system for $50 (CPU + motherboard + 8 GB DDR3) for working with LibreOffice and browsing YouTube — the result was satisfactory.


Comparison with Competitors

- Intel Core i5-2500K (Sandy Bridge): Better IPC (+25%), supports AVX, overclocks to 4.5 GHz. Used — $25.

- AMD Athlon 3000G (2020): 2 cores/4 threads, Vega 3 GPU, 35 watts. New — $60.

- Intel Celeron G6900 (2023): 2 cores, UHD 710, DDR4. New — $50.

Conclusion: The Phenom II X4 840 lags behind even budget modern CPUs but has an advantage in price on the second-hand market.


Practical Build Recommendations

1. SSD is Essential: Kingston A400 240 GB ($20) will speed up system boot times.

2. Graphics Card: Choose GTX 1050 Ti or Radeon RX 560 to avoid imbalance.

3. Cooling: The stock cooler is adequate, but the Arctic Freezer 7X ($15) will reduce noise.

4. BIOS: Update to the latest version for stability.


Final Conclusion: Who Should Consider the Phenom II X4 840?

This processor is suitable for:

- Enthusiasts building retro PCs.

- Budget builds with minimal requirements (office use, surfing).

- Upgrading old systems on AM3 without replacing the motherboard and memory.

Why Does it Still Have Value in 2025?

At the price of a cup of coffee, it provides access to four cores, which is sufficient for less demanding tasks. However, for gaming, video editing, or AI work, it is hopelessly outdated.


Conclusion: The Phenom II X4 840 is a relic of the past that should only be considered in very limited scenarios. For most users, it’s better to add $30-$50 and get a modern Celeron or Athlon with warranty and support for new technologies.

Basic

Label Name
AMD
Platform
Desktop
Launch Date
January 2011
Model Name
?
The Intel processor number is just one of several factors - along with processor brand, system configurations, and system-level benchmarks - to be considered when choosing the right processor for your computing needs.
Phenom II X4 840
Code Name
Propus
Generation
Phenom II X4 (Propus)

CPU Specifications

Total Cores
?
Cores is a hardware term that describes the number of independent central processing units in a single computing component (die or chip).
4
Total Threads
?
Where applicable, Intel® Hyper-Threading Technology is only available on Performance-cores.
4
Basic Frequency
3.2 GHz
Max Turbo Frequency
?
Max Turbo Frequency is the maximum single-core frequency at which the processor is capable of operating using Intel® Turbo Boost Technology and, if present, Intel® Turbo Boost Max Technology 3.0 and Intel® Thermal Velocity Boost. Frequency is typically measured in gigahertz (GHz), or billion cycles per second.
N/A
L1 Cache
128 KB (per core)
L2 Cache
512 KB (per core)
Multiplier
16.0x
Bus Frequency
200 MHz
CPU Socket
?
The socket is the component that provides the mechanical and electrical connections between the processor and motherboard.
AMD Socket AM3
Multiplier Unlocked
No
Technology
?
Lithography refers to the semiconductor technology used to manufacture an integrated circuit, and is reported in nanometer (nm), indicative of the size of features built on the semiconductor.
45 nm
TDP
95 W
PCI Express Version
?
PCI Express Revision is the supported version of the PCI Express standard. Peripheral Component Interconnect Express (or PCIe) is a high-speed serial computer expansion bus standard for attaching hardware devices to a computer. The different PCI Express versions support different data rates.
Gen 2
Transistors
300 million

Memory Specifications

Memory Type
?
Intel® processors come in four different types: Single Channel, Dual Channel, Triple Channel, and Flex Mode. Maximum supported memory speed may be lower when populating multiple DIMMs per channel on products that support multiple memory channels.
DDR2, DDR3
Memory Channels
?
The number of memory channels refers to the bandwidth operation for real world application.
Dual-channel
ECC Memory
Yes

GPU Specifications

Integrated Graphics Model
?
An integrated GPU refers to the graphics core that is integrated into the CPU processor. Leveraging the processor's powerful computational capabilities and intelligent power efficiency management, it delivers outstanding graphics performance and a smooth application experience at a lower power consumption.
On certain motherboards (Chipset feature)

Benchmarks

Geekbench 6
Single Core Score
357
Geekbench 6
Multi Core Score
1024
Geekbench 5
Single Core Score
401
Geekbench 5
Multi Core Score
1296
Passmark CPU
Single Core Score
1299
Passmark CPU
Multi Core Score
2385

Compared to Other CPU

Geekbench 6 Single Core
422 +18.2%
392 +9.8%
312 -12.6%
255 -28.6%
Geekbench 6 Multi Core
1289 +25.9%
1132 +10.5%
927 -9.5%
784 -23.4%
Geekbench 5 Single Core
446 +11.2%
426 +6.2%
365 -9%
331 -17.5%
Geekbench 5 Multi Core
1450 +11.9%
1377 +6.3%
1213 -6.4%
1132 -12.7%
Passmark CPU Single Core
1391 +7.1%
1354 +4.2%
1250 -3.8%
Passmark CPU Multi Core
2807 +17.7%
2629 +10.2%
2254 -5.5%
2094 -12.2%