Core i5-8400 vs Ryzen 9 5900X

CPU

GPU

Core i5-8400

6 Cores6 Thrd65 WWMax: 4 GHz2017

Similar parts

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Ryzen 9 5900X

12 Cores24 Thrd105 WWMax: 4.8 GHz2020

Ryzen family

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Core i5-8400 vs Ryzen 9 5900X Performance Spectrum

Core i5-8400

6 / 6

9,229

0.0%

38,955

+322.1%

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.

Core i5-8400 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.

Core i5-8400 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.

Core i5-8400

2017

Why buy it

✅Costs $367 less on MSRP ($182 MSRP vs $549 MSRP).
✅Draws 65W instead of 105W, a 40W reduction.
✅Integrated graphics onboard with UHD Graphics 630, while Ryzen 9 5900X needs a discrete GPU.

Trade-offs

❌Worse for gaming: lower average FPS than Ryzen 9 5900X across 50 shared CPU benchmark tests.
❌Lower PassMark (9,229 vs 38,955).
❌Smaller total L3 cache (9 MB vs 64 MB).
❌Lower PassMark per dollar, at 50.7 vs 71.0 PassMark/$ ($182 MSRP vs $549 MSRP).

Ryzen 9 5900X

2020

Why buy it

✅Better for gaming: +120.1% higher average FPS across 50 shared CPU benchmark tests.
✅+611.1% larger total L3 cache (64 MB vs 9 MB).
✅Delivers 39.9% more PassMark for each dollar spent, at 71.0 vs 50.7 PassMark/$ ($549 MSRP vs $182 MSRP).
✅50% more PCIe lanes (24 vs 16) for storage and expansion-heavy builds.

Trade-offs

❌
201.6% HIGHER MSRP
$549 MSRPvs$182 MSRP
❌61.5% higher power demand at 105W vs 65W.
❌No integrated graphics, while Core i5-8400 can still boot and troubleshoot without a discrete GPU.

Quick Answers

So, is Ryzen 9 5900X better than Core i5-8400?

Yes. Ryzen 9 5900X is the better all-around CPU here. It gives you a 120.1% average FPS lead across 50 shared CPU game tests in our data, 322.1% 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 120.1% 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 322.1% better PassMark, backed by 12 cores and 24 threads. It also has the larger cache pool with 611.1% larger total L3 cache (64 MB vs 9 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 201.6% more expensive on MSRP at $549 MSRP versus $182 MSRP, and it still gives you a 120.1% average FPS lead across 50 shared CPU game tests in our data. It is also 39.9% better value on MSRP (71.0 vs 50.7 PassMark/$), 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 2017), 611.1% larger total L3 cache (64 MB vs 9 MB), and more multi-core headroom with 12 cores / 24 threads instead of 6/6. That extra compute headroom is more likely to matter as games, background tasks, and creator workloads get heavier.

Core i5-8400 vs Ryzen 9 5900X Technical Specifications

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

Core i5-8400

The Core i5-8400 is manufactured by Intel. It was released in 5 October 2017 (8 years ago). It is based on the Coffee Lake-S (2017−2018) architecture. It features 6 cores and 6 threads. Base frequency is 2.8 GHz, with boost up to 4 GHz. L3 cache: 9 MB (total). L2 cache: 256K (per core). Built on 14 nm process technology. Socket: LGA1151. Thermal design power (TDP): 65 Watt. Memory support: DDR3, DDR4. Passmark benchmark score: 9,229 points. Launch price was $182.

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 Core i5-8400 packs 6 cores / 6 threads, while the Ryzen 9 5900X offers 12 cores / 24 threads — the Ryzen 9 5900X has 6 more cores. Boost clocks reach 4 GHz on the Core i5-8400 versus 4.8 GHz on the Ryzen 9 5900X — a 18.2% clock advantage for the Ryzen 9 5900X (base: 2.8 GHz vs 3.7 GHz). The Core i5-8400 uses the Coffee Lake-S (2017−2018) architecture (14 nm), while the Ryzen 9 5900X uses Vermeer (Zen3) (2020−2022) (7 nm, 12 nm). In PassMark, the Core i5-8400 scores 9,229 against the Ryzen 9 5900X's 38,955 — a 123.4% lead for the Ryzen 9 5900X. L3 cache: 9 MB (total) on the Core i5-8400 vs 64 MB on the Ryzen 9 5900X.

Feature	Core i5-8400	Ryzen 9 5900X
Cores / Threads	6 / 6	12 / 24+100%
Boost Clock	4 GHz	4.8 GHz+20%
Base Clock	2.8 GHz	3.7 GHz+32%
L3 Cache	9 MB (total)	64 MB+611%
L2 Cache	256K (per core)	512K (per core)+100%
Process	14 nm	7 nm, 12 nm-50%
Architecture	Coffee Lake-S (2017−2018)	Vermeer (Zen3) (2020−2022)
PassMark	9,229	38,955+322%
Cinebench R23 Multi	—	21,000
Geekbench 6 Single	—	2,174
Geekbench 6 Multi	—	11,888

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Memory & Platform

The Core i5-8400 uses the LGA1151 socket (PCIe 3.0), while the Ryzen 9 5900X uses AM4 (PCIe 4.0) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR4-2666 on the Core i5-8400 versus DDR4-3200 on the Ryzen 9 5900X — the Ryzen 9 5900X supports 20% faster memory, which can translate to measurable gains in memory-sensitive workloads. Both support up to 128 GB of RAM. Both feature 2-channel memory with ECC support. PCIe lanes: 16 (Core i5-8400) vs 24 (Ryzen 9 5900X) — the Ryzen 9 5900X offers 8 more lanes for additional GPUs or NVMe drives. Chipset compatibility: Intel 300 series (Core i5-8400) and A320,B350,X370,B450,X470,B550,X570 (Ryzen 9 5900X).

Feature	Core i5-8400	Ryzen 9 5900X
Socket	LGA1151	AM4
PCIe Generation	PCIe 3.0	PCIe 4.0+33%
Max RAM Speed	DDR4-2666	DDR4-3200+20%
Max RAM Capacity	128 GB	128 GB
RAM Channels	2	2
ECC Support	No	Yes
PCIe Lanes	16	24+50%

🔧

Advanced Features

Only the Ryzen 9 5900X has an unlocked multiplier for overclocking — a significant advantage for enthusiasts seeking extra performance. Virtualization support: VT-x, VT-d (Core i5-8400) vs AMD-V (Ryzen 9 5900X). The Core i5-8400 includes integrated graphics (UHD Graphics 630), while the Ryzen 9 5900X requires a dedicated GPU. Primary use case: Core i5-8400 targets Desktop, Ryzen 9 5900X targets Workstation. Direct competitor: Ryzen 9 5900X rivals Core i9-12900K.

Feature	Core i5-8400	Ryzen 9 5900X
Integrated GPU	Yes	No
IGPU Model	UHD Graphics 630	—
Unlocked	No	Yes
AVX-512	No	No
Virtualization	VT-x, VT-d	AMD-V
Target Use	Desktop	Workstation

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Value Analysis

At launch, the Core i5-8400 was priced at $182, while the Ryzen 9 5900X came in at $549. On launch pricing ($182 vs $549), Core i5-8400 was $367 cheaper. In terms of value on MSRP (PassMark points per dollar), the Core i5-8400 delivers 50.7 pts/$ vs 71.0 pts/$ for the Ryzen 9 5900X — making the Ryzen 9 5900X the 33.3% better value option.

Feature	Core i5-8400	Ryzen 9 5900X
MSRP	$182-67%	$549
Performance per Dollar	50.7	71.0+40%
Release Date	2017	2020

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