FX-8120 vs Ryzen 9 5900X

CPU

GPU

FX-8120

8 Cores8 Thrd125 WWMax: 4 GHz2011

Similar parts

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Ryzen 9 5900X

12 Cores24 Thrd105 WWMax: 4.8 GHz2020

Ryzen family

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FX-8120 vs Ryzen 9 5900X Performance Spectrum

FX-8120

8 / 8

6,594

0.0%

Ryzen Threadripper 3970X

Ryzen Threadripper PRO 7965WX

Ryzen 9 5900X

12 / 24

38,955

+490.8%

Ryzen Threadripper 9960X

Ryzen Threadripper PRO 9975WX

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.

FX-8120 vs Ryzen 9 5900X 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.

FX-8120 vs Ryzen 9 5900X: Pros, Cons & Final Verdict

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

FX-8120

2011

Why buy it

✅Costs $344 less on MSRP ($205 MSRP vs $549 MSRP).

Trade-offs

❌Worse for gaming: lower average FPS than Ryzen 9 5900X across 50 shared CPU benchmark tests.
❌Lower PassMark (6,594 vs 38,955).
❌Smaller total L3 cache (8 MB vs 64 MB).
❌Lower PassMark per dollar, at 32.2 vs 71.0 PassMark/$ ($205 MSRP vs $549 MSRP).
❌19% higher power demand at 125W vs 105W.

Ryzen 9 5900X

2020

Why buy it

✅Better for gaming: +128.7% higher average FPS across 50 shared CPU benchmark tests.
✅+700% larger total L3 cache (64 MB vs 8 MB).
✅Delivers 120.6% more PassMark for each dollar spent, at 71.0 vs 32.2 PassMark/$ ($549 MSRP vs $205 MSRP).
✅Draws 105W instead of 125W, a 20W reduction.
✅100+% more PCIe lanes (24 vs 0) for storage and expansion-heavy builds.

Trade-offs

❌
167.8% HIGHER MSRP
$549 MSRPvs$205 MSRP

Quick Answers

So, is Ryzen 9 5900X better than FX-8120?

Yes. Ryzen 9 5900X is the better all-around CPU here. It gives you a 128.7% average FPS lead across 50 shared CPU game tests in our data, 490.8% better PassMark, and the stronger long-term platform, which is enough to make it the stronger overall pick.

Which one is better for gaming?

If gaming is the priority, Ryzen 9 5900X is the better pick. According to our tests, it delivers 128.7% 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, Ryzen 9 5900X is the stronger fit. You are getting 490.8% better PassMark, backed by 12 cores and 24 threads. It also has the larger cache pool with 700% larger total L3 cache (64 MB vs 8 MB).

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

Ryzen 9 5900X is the better buy right now. Ryzen 9 5900X comes in 167.8% more expensive on MSRP at $549 MSRP versus $205 MSRP, and it still gives you a 128.7% average FPS lead across 50 shared CPU game tests in our data. It is also 120.6% better value on MSRP (71.0 vs 32.2 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

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

Ryzen 9 5900X makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2020 vs 2011), 700% larger total L3 cache (64 MB vs 8 MB), and more multi-core headroom with 12 cores / 24 threads instead of 8/8. That extra compute headroom is more likely to matter as games, background tasks, and creator workloads get heavier.

FX-8120 vs Ryzen 9 5900X Technical Specifications

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

FX-8120

The FX-8120 is manufactured by AMD. It was released in 12 October 2011 (14 years ago). It is based on the Zambezi (2011−2012) architecture. It features 8 cores and 8 threads. Base frequency is 3.1 GHz, with boost up to 4 GHz. L3 cache: 8192 kB. L2 cache: 8192 kB. Built on 32 nm process technology. Socket: AM3+. Thermal design power (TDP): 125 Watt. Memory support: DDR3. Passmark benchmark score: 6,594 points. Launch price was $149.

Ryzen 9 5900X

The Ryzen 9 5900X is manufactured by AMD. It was released in 5 November 2020 (5 years ago). It is based on the Vermeer (Zen3) (2020−2022) architecture. It features 12 cores and 24 threads. Base frequency is 3.7 GHz, with boost up to 4.8 GHz. L3 cache: 64 MB. L2 cache: 512K (per core). Built on 7 nm, 12 nm process technology. Socket: AM4. Thermal design power (TDP): 105 Watt. Memory support: DDR4-3200. Passmark benchmark score: 38,955 points. Launch price was $549.

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Processing Power

The FX-8120 packs 8 cores / 8 threads, while the Ryzen 9 5900X offers 12 cores / 24 threads — the Ryzen 9 5900X has 4 more cores. Boost clocks reach 4 GHz on the FX-8120 versus 4.8 GHz on the Ryzen 9 5900X — a 18.2% clock advantage for the Ryzen 9 5900X (base: 3.1 GHz vs 3.7 GHz). The FX-8120 uses the Zambezi (2011−2012) architecture (32 nm), while the Ryzen 9 5900X uses Vermeer (Zen3) (2020−2022) (7 nm, 12 nm). In PassMark, the FX-8120 scores 6,594 against the Ryzen 9 5900X's 38,955 — a 142.1% lead for the Ryzen 9 5900X. L3 cache: 8192 kB on the FX-8120 vs 64 MB on the Ryzen 9 5900X.

Feature	FX-8120	Ryzen 9 5900X
Cores / Threads	8 / 8	12 / 24+50%
Boost Clock	4 GHz	4.8 GHz+20%
Base Clock	3.1 GHz	3.7 GHz+19%
L3 Cache	8192 kB	64 MB+700%
L2 Cache	8192 kB+1500%	512K (per core)
Process	32 nm	7 nm, 12 nm-78%
Architecture	Zambezi (2011−2012)	Vermeer (Zen3) (2020−2022)
PassMark	6,594	38,955+491%
Cinebench R23 Multi	—	21,000
Geekbench 6 Single	—	2,174
Geekbench 6 Multi	—	11,888

🧠

Memory & Platform

The FX-8120 uses the AM3+ socket (PCIe 2.0), while the Ryzen 9 5900X uses AM4 (PCIe 4.0) — making them incompatible on the same motherboard.

Feature	FX-8120	Ryzen 9 5900X
Socket	AM3+	AM4
PCIe Generation	PCIe 2.0	PCIe 4.0+100%
Max RAM Speed	—	DDR4-3200
Max RAM Capacity	—	128 GB
RAM Channels	—	2
ECC Support	—	Yes
PCIe Lanes	—	24

🔧

Advanced Features

Virtualization: not specified (FX-8120) / AMD-V (Ryzen 9 5900X). Primary use case: Ryzen 9 5900X targets Workstation. Direct competitor: Ryzen 9 5900X rivals Core i9-12900K.

Feature	FX-8120	Ryzen 9 5900X
Integrated GPU	—	No
Unlocked	—	Yes
AVX-512	—	No
Virtualization	—	AMD-V
Target Use	—	Workstation

💰

Value Analysis

At launch, the FX-8120 was priced at $205, while the Ryzen 9 5900X came in at $549. On launch pricing ($205 vs $549), FX-8120 was $344 cheaper. In terms of value on MSRP (PassMark points per dollar), the FX-8120 delivers 32.2 pts/$ vs 71.0 pts/$ for the Ryzen 9 5900X — making the Ryzen 9 5900X the 75.2% better value option.

Feature	FX-8120	Ryzen 9 5900X
MSRP	$205-63%	$549
Performance per Dollar	32.2	71.0+120%
Release Date	2011	2020

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