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AMD Athlon II X4 651K

AMD Athlon II X4 651K

AMD Athlon II X4 651K: A Budget Veteran in 2025

Updated: April 2025

1. Key Specs: Architecture and Capabilities

The AMD Athlon II X4 651K processor, released in 2011, remains a niche solution for enthusiasts and budget builds. Its Llano architecture (32 nm) is based on K10.5 cores, which once competed with Intel's Core 2 Quad.

Technical Specifications:

- Cores/Threads: 4/4 (no support for Hyper-Threading or SMT).

- Base Clock Speed: 3.0 GHz (no Turbo Boost).

- Cache: L2 — 4×1 MB (L3 is absent).

- TDP: 100 W.

- Unlocked Multiplier: Yes (the "K" identifier allows for overclocking).

Key Features:

- Affordable Multitasking: Four physical cores handle basic tasks (office work, browsing, media).

- FM1 Compatibility: Allows the use of old motherboards.

- Low Cost: New units (if you can find them) cost between $30–50.

Limitations:

- No support for AVX, AES-NI, and other modern instructions.

- No integrated graphics — a discrete GPU is required.

2. Compatible Motherboards: FM1 Socket and Chipsets

The Athlon II X4 651K only fits into the FM1 socket, making the search for motherboards in 2025 challenging.

Chipsets:

- A75: The best option — supports USB 3.0, SATA III (6 Gbps).

- A55: Budget choice, but only offers SATA II and USB 2.0.

Recommendations:

- Popular models: ASUS F1A75-M PRO, Gigabyte GA-A55M-DS2.

- Prices: New boards are rare, but remnants sell for $60–100.

Important:

- The motherboard's BIOS must support the processor (check versions).

- PCIe 2.0 x16 is sufficient for mid-range GPUs like the GTX 1050 Ti.

3. Supported Memory: Only DDR3

The Athlon II X4 651K works with DDR3-1866 (officially supports up to DDR3-1600).

Recommendations:

- Optimal capacity: 8–16 GB (2×4 GB or 2×8 GB).

- Timings: CL9–CL11.

Examples:

- Kingston HyperX Blu (1600 MHz, CL9) — $25 for 8 GB (new kit).

- Important: The motherboard must support the chosen frequency.

Limitations:

- No support for DDR4/DDR5 — upgrades are impossible without changing platforms.

4. Power Supply: Calculating for 100 W TDP

When building a system with the X4 651K, consider the power consumption of the components:

Recommended PSU Wattage:

- Without a discrete GPU: 300 W (but this scenario is pointless since the processor has no iGPU).

- With a GTX 1650 GPU: 450–500 W.

PSU Examples:

- EVGA 500 BR (500 W, 80+ Bronze) — $45.

- Important: Don’t skimp on the power supply — cheap models can damage components.

Tip: Use calculators (like OuterVision) for accurate calculations.

5. Pros and Cons of Athlon II X4 651K

Pros:

- Price: One of the cheapest 4-core processors on the market ($30–50).

- Overclocking: Potential to increase the clock speed to 3.5–3.8 GHz (depends on cooling).

- OS Compatibility: Works with Windows 10/11 and Linux.

Cons:

- Outdated Architecture: Lags behind even budget 2025 Intel Celerons in single-core performance.

- Higher Power Consumption: 100 W versus 35–65 W for modern equivalents.

- No PCIe 3.0/4.0: Limits the selection of GPUs and NVMe storage.

6. Use Cases: What Tasks Is It Suitable For?

- Office and Web: Working with documents, Zoom, 10+ tabs in a browser (with 8+ GB RAM).

- Multimedia: Watching 1080p/4K videos (with hardware decoding via the GPU).

- Light Gaming: CS:GO, Dota 2, Minecraft (60 FPS at low settings with a GTX 1050 level GPU).

- Server Tasks: NAS or home media server (thanks to 4 cores).

Real Experience:

A user in Brazil built a PC with the X4 651K, Radeon RX 560, and 16 GB DDR3. The system runs GTA V at medium settings (45–60 FPS), but even on minimal settings in Cyberpunk 2077, it achieves only 20–25 FPS.

7. Comparison with Competitors

Intel Pentium G3420 (Haswell, 2013):

- 2 cores/2 threads, 3.2 GHz.

- Pros: Low TDP (54 W), AVX2 support.

- Cons: Lower multitasking capability.

- Price: $40–60 (new).

AMD Ryzen 3 1200 (2017):

- 4 cores/4 threads, 14 nm, TDP 65 W.

- Pros: DDR4 support, PCIe 3.0, overclocking.

- Cons: Requires AM4 socket (motherboards are more expensive).

- Price: $60–80 (new).

Conclusion: In 2025, the Athlon II X4 651K lags behind even older Ryzen processors, but it wins in price.

8. Practical Assembly Tips

- Motherboard: Look for A75 with USB 3.0 and SATA III.

- Cooling: Budget $20–30 for a cooler (e.g., Deepcool Gammaxx 400).

- Storage: SSD is essential (Kingston A400 240 GB — $25).

- GPU: No higher than GTX 1660 Super — the processor will bottleneck.

Sample Build for $250:

- CPU: Athlon II X4 651K ($40).

- Motherboard: ASUS F1A75-M (used, $50).

- RAM: 8 GB DDR3 ($20).

- GPU: GTX 1050 Ti (used, $70).

- SSD: 240 GB ($25).

- PSU: 450 W ($45).

9. Final Verdict: Who Is the Athlon II X4 651K Suitable For?

This processor is ideal for:

1. Enthusiasts building retro PCs or test benches.

2. Budget users needing a PC for internet and office tasks for $200–300.

3. Temporary solutions while saving for a modern platform.

Who Should Avoid It? If you plan to play new games or work with graphics — even the Ryzen 3 2200G (2018) will be 2–3 times faster.

Conclusion: The Athlon II X4 651K in 2025 is a "workhorse" for very specific tasks. It is worth buying only if you are severely budget-constrained or want to revive an old PC. In all other cases, it’s better to consider used Ryzen or Intel 8th generation options.

Basic

Label Name
AMD
Platform
Desktop
Launch Date
November 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.
Athlon II X4 651K
Code Name
Llano
Generation
Athlon II X4 (Llano)

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 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
1 MB (per core)
Multiplier Unlocked
Yes
CPU Socket
?
The socket is the component that provides the mechanical and electrical connections between the processor and motherboard.
AMD Socket FM1
Multiplier
30.0x
Bus Frequency
100 MHz
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.
32 nm
TDP
100 W
Max. Operating Temperature
?
Junction Temperature is the maximum temperature allowed at the processor die.
70°C
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
1,178 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.
DDR3
Memory Channels
?
The number of memory channels refers to the bandwidth operation for real world application.
Dual-channel
ECC Memory
No

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.
N/A