AMD Athlon II X4 651
AMD Athlon II X4 651: A Budget Veteran of 2025. Is It Worth Considering?
Key Specifications: Architecture, fabrication process, and features
The AMD Athlon II X4 651 processor, released in 2011, belongs to the era when multi-core CPUs were just beginning to capture the mainstream market. Its codename is Llano, and the fabrication process is 32 nm, which seems archaic by 2025 standards (modern chips use 5–7 nm). The architecture is based on K10.5 cores, which do not support key modern instructions like AVX2 or AES-NI.
Key parameters:
- 4 cores / 4 threads — basic multitasking capability, but no hyperthreading.
- Base frequency: 3.0 GHz (without Turbo Boost).
- TDP: 100 W — high for its performance.
- L2 Cache: 4×1 MB, absence of L3 cache.
Geekbench 6 shows modest results:
- Single-core: 333 (for comparison, Ryzen 3 5300G — 1500+).
- Multi-core: 1109 (comparable to the Intel Core i3-2130).
Features for 2025:
- Integrated graphics Radeon HD 3000 (only in "K" versions). However, the X4 651 lacks this — it is a pure CPU.
- DDR3 support — inexpensive memory but limits performance.
Compatible Motherboards: Socket FM1 and Selection Nuances
The processor uses the outdated FM1 socket, which was discontinued back in 2013. Main chipsets include:
- A55 — base model: USB 2.0, SATA II.
- A75 — enhanced version: USB 3.0, SATA III.
Popular motherboards for 2025:
No new FM1 motherboards are being produced, but used options can be found on the secondary market (eBay, AliExpress):
- Gigabyte GA-A75M-DS2 (used price: $20–30).
- ASRock A55M-HVS (used price: $15–25).
Important:
- BIOS updates are impossible — the last versions were released in 2013–2014.
- No NVMe or M.2 support — only SATA drives.
Supported Memory: Only DDR3
The Athlon II X4 651 works with DDR3 (does not support DDR4/DDR5).
- Official frequency: Up to 1866 MHz (with overclocking).
- Recommended capacity: 8–16 GB (2×4 GB or 2×8 GB).
Example configuration:
- Kingston HyperX Fury DDR3-1866 (8 GB) — $25–35 per module (new stock).
Limitations:
DDR3 bandwidth in 2025 critically lags behind DDR4/DDR5, affecting rendering speed and gaming performance.
Power Supply: Calculation for a 100 W TDP System
The processor consumes up to 100 W under load. A power supply of 400–450 W is suitable for building with it, but with reserve for a discrete graphics card:
- Integrated graphics: 300–350 W (for example, EVGA 400 N1, $35–40).
- Discrete graphics card (e.g., GTX 1650): 450–500 W (Corsair CX450, $50–60).
Tip:
Avoid cheap noname power supplies. Even for an old system, stability is important — choose models with an 80+ Bronze certification.
Pros and Cons of Athlon II X4 651
Pros:
1. Super budget-friendly price: New stock — $40–60 (for 2025).
2. 4 physical cores — better than dual-core competitors from the 2010s.
3. Simple assembly — suitable for reviving an old PC.
Cons:
1. Outdated architecture — 200–300% IPC lag compared to modern CPUs.
2. High power consumption — 100 W compared to 65 W for Ryzen 3 5300G.
3. No support for modern interfaces (USB 3.1, PCIe 4.0).
Use Cases: Where is the X4 651 Still Relevant?
1. Office tasks: Working with documents, browsers, light applications.
Example: A system with SSD and 8 GB RAM handles LibreOffice and 10+ Chrome tabs.
2. Multimedia: Watching Full HD video, streaming (but not encoding).
Example: HTPC with Kodi or Plex connected to a TV.
3. Light gaming:
- CS:GO: 40–50 FPS on low settings (with a GPU like GTX 750 Ti).
- Minecraft: 60 FPS without mods.
Unsuitable tasks:
- 4K video editing, AI tools, modern games (Cyberpunk 2077, Starfield).
Comparison with Competitors
1. Intel Core i5-2500K (Sandy Bridge):
- Better single-core performance (~450 in Geekbench 6).
- PCIe 3.0 support.
- Used price: $50–70.
2. AMD Phenom II X4 965:
- Similar performance, but higher heat output (125 W).
- AM3 socket — more motherboard options.
3. Modern budget CPUs of 2025:
- Ryzen 3 5300G: 4 times faster, TDP 65 W, price $120.
- Intel Core i3-14100F: Single-core score ~1800, price $110.
Conclusion: The X4 651 lags behind even budget CPUs of 2025, but it can be a temporary solution for a budget under $100.
Practical Assembly Tips
1. Motherboard: Look for models with the A75 chipset — they support USB 3.0.
2. Cooling: The stock cooler is sufficient, but replace the thermal paste (e.g., Arctic MX-4).
3. SSD is a must: Kingston A400 240 GB ($25) will speed up OS loading.
4. Graphics Card: Choose models without additional power requirements (GTX 1050, RX 560).
5. OS: Windows 10 LTSC or Linux (Ubuntu LTS) — minimal background processes.
Final Conclusion: Who is the Athlon II X4 651 For?
This processor is a choice for:
1. Enthusiasts reviving 2010s PCs for nostalgic builds.
2. Budget users needing a PC for basic tasks (up to $150 for the system).
3. Temporary solutions, for example, for a child or as a second computer.
Alternative: If the budget allows for $200–300, it’s better to get a Ryzen 3 5300G or Intel i3-14100F — they will provide headroom for 3–5 years.
Main argument for the X4 651: It exists. When other options are unavailable, this CPU can enable you to build a working machine for little money. But remember — this is a last resort, not a sensible upgrade in 2025.