Athlon X4 840 vs Opteron X3421

Athlon X4 840 vs Opteron X3421 Performance Spectrum

Athlon X4 840

4 / 4

3,331

+0.8%

Ryzen Threadripper 3990X

Opteron X3421

4 / 4

3,306

0.0%

Ryzen Threadripper 3990X

About PassMark

PassMark CPU Mark evaluates processor speed through complex mathematical computations. It provides a reliable metric to compare multi-core performance, where higher scores indicate faster processing for multitasking, gaming, and heavy workloads.

Athlon X4 840 vs Opteron X3421 FPS Benchmarks

Predicted gaming performance across popular games. Tested paired with GeForce RTX 5090 to isolate CPU performance.

Search any supported game below to compare 1080p FPS for both components.

Athlon X4 840 vs Opteron X3421: Pros, Cons & Final Verdict

See where each CPU makes more sense in practice: gaming, heavier work, platform cost, power draw, and upgrade path.

Athlon X4 840

2014

Why buy it

✅Better for gaming: +4.7% higher average FPS across 50 shared CPU benchmark tests.
✅100+% more PCIe lanes (16 vs 0) for storage and expansion-heavy builds.

Trade-offs

❌Launch MSRP is still $102 MSRP, while Opteron X3421 mostly shows up through inconsistent older-market listings.
❌333.3% higher power demand at 65W vs 15W.

Opteron X3421

2017

Why buy it

✅Draws 15W instead of 65W, a 50W reduction.

Trade-offs

❌Worse for gaming: lower average FPS than Athlon X4 840 across 50 shared CPU benchmark tests.
❌Lower PassMark (3,306 vs 3,331).

Quick Answers

So, is Athlon X4 840 better than Opteron X3421?

Not really, because they are built for different jobs. Opteron X3421 makes more sense for workstation-style multi-core throughput, while Athlon X4 840 is the more practical desktop choice for gaming, platform cost, and everyday use.

Which one is better for gaming?

If gaming is the priority, Athlon X4 840 is the better pick. According to our tests, it delivers 4.7% more average FPS across 50 shared CPU game tests.

Which one is better for streaming, content creation, and heavy multitasking?

For streaming, content creation, and heavier multitasking, Athlon X4 840 is the stronger fit. You are getting 0.8% better PassMark, backed by 4 cores and 4 threads.

Which one is the smarter buy today, not just the cheaper CPU?

Athlon X4 840 is the better buy right now. Athlon X4 840 comes in at an unclear MSRP at $102 MSRP versus unclear MSRP, and it still gives you a 4.7% average FPS lead across 50 shared CPU game tests in our data. It is also 100.0% better value on MSRP (32.7 vs 0.0 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

Which one is more future-proof for 2026 and beyond?

Opteron X3421 makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2017 vs 2014). That makes it the safer long-term bet.

Athlon X4 840 vs Opteron X3421 Technical Specifications

Side-by-side specs, architecture details, clocks, memory, power, and platform differences.

Athlon X4 840

The Athlon X4 840 is manufactured by AMD. It was released in 2009-01-01. It is based on the Kaveri (2014−2015) architecture. It features 4 cores and 4 threads. Base frequency is 3.1 GHz, with boost up to 3.8 GHz. L2 cache: 4 MB. Built on 28 nm process technology. Socket: FM2+. Thermal design power (TDP): 65 watt. Memory support: DDR3. Passmark benchmark score: 3,331 points. Launch price was $149.

Opteron X3421

The Opteron X3421 is manufactured by AMD. It was released in 2015-01-01. It is based on the Excavator (2017−2018) architecture. It features 4 cores and 4 threads. Base frequency is 2.1 GHz, with boost up to 3.4 GHz. L2 cache: 2 MB (total). Built on 28 nm process technology. Socket: FP4. Thermal design power (TDP): 15 Watt. Memory support: DDR4. Passmark benchmark score: 3,306 points. Launch price was $800.

⚡

Processing Power

Both the Athlon X4 840 and Opteron X3421 share an identical 4-core/4-thread configuration. Boost clocks reach 3.8 GHz on the Athlon X4 840 versus 3.4 GHz on the Opteron X3421 — a 11.1% clock advantage for the Athlon X4 840 (base: 3.1 GHz vs 2.1 GHz). The Athlon X4 840 uses the Kaveri (2014−2015) architecture (28 nm), while the Opteron X3421 uses Excavator (2017−2018) (28 nm). In PassMark, the Athlon X4 840 scores 3,331 against the Opteron X3421's 3,306 — a 0.8% lead for the Athlon X4 840.

Feature	Athlon X4 840	Opteron X3421
Cores / Threads	4 / 4	4 / 4
Boost Clock	3.8 GHz+12%	3.4 GHz
Base Clock	3.1 GHz+48%	2.1 GHz
L2 Cache	4 MB+100%	2 MB (total)
Process	28 nm	28 nm
Architecture	Kaveri (2014−2015)	Excavator (2017−2018)
PassMark	3,331	3,306

🧠

Memory & Platform

The Athlon X4 840 uses the FM2+ socket (PCIe 3.0), while the Opteron X3421 uses FP4 (PCIe 3.0) — making them incompatible on the same motherboard.