Core i5-8257U vs Core i5-8400T

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 i5-8257U vs Core i5-8400T 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 i5-8257U vs Core i5-8400T: Pros, Cons & Final Verdict

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

Core i5-8257U

2019

Why buy it

✅Better for gaming: +7.4% higher average FPS across 50 shared CPU benchmark tests.
✅Draws 1W instead of 35W, a 34W reduction.

Trade-offs

❌Smaller total L3 cache (6 MB vs 9 MB).
❌No boxed cooler included, unlike Core i5-8400T.

Core i5-8400T

2018

Why buy it

✅+50% larger total L3 cache (9 MB vs 6 MB).
✅Includes a boxed cooler (Yes), unlike Core i5-8257U.

Trade-offs

❌Worse for gaming: lower average FPS than Core i5-8257U across 50 shared CPU benchmark tests.
❌Lower Cinebench R23 multi-core (3,737 vs 4,017).
❌Launch MSRP is still $182 MSRP, while Core i5-8257U mostly shows up through inconsistent older-market listings.
❌3400% higher power demand at 35W vs 1W.

Quick Answers

So, is Core i5-8257U better than Core i5-8400T?

Yes. Core i5-8257U is the better all-around CPU here. It gives you a 7.4% average FPS lead across 50 shared CPU game tests in our data, 7.5% better Cinebench R23 multi-core, 0.0% higher 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, Core i5-8257U is the better pick. According to our tests, it delivers 7.4% 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, Core i5-8257U is the stronger fit. You are getting 7.5% better Cinebench R23 multi-core, backed by 4 cores and 8 threads.

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

Core i5-8257U is still the much better call for a fresh build. Core i5-8257U comes in at an unclear MSRP at unclear MSRP versus $182 MSRP, and it still gives you a 7.4% average FPS lead across 50 shared CPU game tests in our data. Core i5-8400T only looks stronger on raw value math because it is extremely cheap, but that usually means used-market pricing on an obsolete 2018 platform. Even with 100.0% better value on paper (40.8 vs 0.0 PassMark/$), it really only makes sense as a cheap stopgap or a niche existing-platform option for someone already on LGA1151.

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

Core i5-8257U makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2019 vs 2018) and more multi-core headroom with 4 cores / 8 threads instead of 6/6. That extra compute headroom is more likely to matter as games, background tasks, and creator workloads get heavier.

Core i5-8257U vs Core i5-8400T Technical Specifications

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

Core i5-8257U

The Core i5-8257U is manufactured by Intel. It was released in 10 July 2019 (6 years ago). It is based on the Coffee Lake-U (2018−2019) architecture. It features 4 cores and 8 threads. Base frequency is 1.4 GHz, with boost up to 3.9 GHz. L3 cache: 6 MB. L2 cache: 1 MB. Built on 14 nm process technology. Socket: FCBGA1528. Thermal design power (TDP): 15 Watt. Memory support: DDR4. Passmark benchmark score: 7,427 points. Launch price was $149.

Core i5-8400T

The Core i5-8400T is manufactured by Intel. It was released in 2 April 2018 (7 years ago). It is based on the Coffee Lake (2017−2019) architecture. It features 6 cores and 6 threads. Base frequency is 1.7 GHz, with boost up to 3.3 GHz. L3 cache: 9 MB (total). L2 cache: 256K (per core). Built on 14 nm process technology. Socket: LGA1151. Thermal design power (TDP): 35 Watt. Memory support: DDR4-2666. Passmark benchmark score: 7,426 points. Launch price was $182.

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Processing Power

The Core i5-8257U packs 4 cores / 8 threads, while the Core i5-8400T offers 6 cores / 6 threads — the Core i5-8400T has 2 more cores. Boost clocks reach 3.9 GHz on the Core i5-8257U versus 3.3 GHz on the Core i5-8400T — a 16.7% clock advantage for the Core i5-8257U (base: 1.4 GHz vs 1.7 GHz). The Core i5-8257U uses the Coffee Lake-U (2018−2019) architecture (14 nm), while the Core i5-8400T uses Coffee Lake (2017−2019) (14 nm). In PassMark, the Core i5-8257U scores 7,427 against the Core i5-8400T's 7,426 — a 0% lead for the Core i5-8257U. Cinebench R23 multi-core: 4,017 vs 3,737 (7.2% advantage for the Core i5-8257U). Geekbench 6 single-core — the metric most relevant to gaming — records 1,100 vs 1,092, a 0.7% lead for the Core i5-8257U that directly translates to higher frame rates. Multi-core Geekbench: 4,000 vs 3,816 (4.7% advantage for the Core i5-8257U). L3 cache: 6 MB on the Core i5-8257U vs 9 MB (total) on the Core i5-8400T.

Feature	Core i5-8257U	Core i5-8400T
Cores / Threads	4 / 8	6 / 6+50%
Boost Clock	3.9 GHz+18%	3.3 GHz
Base Clock	1.4 GHz	1.7 GHz+21%
L3 Cache	6 MB	9 MB (total)+50%
L2 Cache	1 MB	256K (per core)+25500%
Process	14 nm	14 nm
Architecture	Coffee Lake-U (2018−2019)	Coffee Lake (2017−2019)
PassMark	7,427	7,426
Cinebench R23 Multi	4,017+7%	3,737
Geekbench 6 Single	1,100	1,092
Geekbench 6 Multi	4,000+5%	3,816

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Memory & Platform

The Core i5-8257U uses the FCBGA1528 socket (PCIe 3.0), while the Core i5-8400T uses LGA1151 (PCIe 3.0) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR4-2400 on the Core i5-8257U versus DDR4-2666 on the Core i5-8400T — the Core i5-8400T supports 11.1% faster memory, which can translate to measurable gains in memory-sensitive workloads. The Core i5-8400T supports up to 128 GB of RAM compared to 32 GB — 300% more capacity for professional workloads. Both feature 2-channel memory with ECC support. Both provide 16 PCIe lanes. Chipset compatibility: 300 Series (Core i5-8257U) and H310,B360,H370,Q370,Z370,Z390 (Core i5-8400T).

Feature	Core i5-8257U	Core i5-8400T
Socket	FCBGA1528	LGA1151
PCIe Generation	PCIe 3.0	PCIe 3.0
Max RAM Speed	DDR4-2400	DDR4-2666+11%
Max RAM Capacity	32 GB	128 GB+300%
RAM Channels	2	2
ECC Support	No	No
PCIe Lanes	16	16

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Advanced Features

Virtualization support: VT-x, VT-d (Core i5-8257U) vs Yes (Core i5-8400T). Both include integrated graphics — Intel Iris Plus Graphics 645 (Core i5-8257U) and UHD Graphics 630 (Core i5-8400T) — useful as a fallback for troubleshooting or display output without a dedicated GPU. Primary use case: Core i5-8257U targets Ultrabook.