Quick Verdict
A highly efficient 6-core processor perfect for compact builds, though its low clock speeds limit performance compared to the standard 8400.
Overview
Launch
2018
Status
End-of-lifeGeneration
8th Generation (Coffee Lake)
Market
Desktop
The Intel Core i5-8400T is a low-power desktop processor belonging to the 8th generation Coffee Lake family. Released in April 2018, it is built on the 14nm process and features 6 cores and 6 threads. Unlike the standard i5-8400, the 'T' suffix denotes a reduced 35W TDP, making it ideal for small form factor (SFF) PCs and home theater setups. The base clock is set at 1.7 GHz, with a maximum turbo boost of 3.3 GHz. It includes 9 MB of Intel Smart Cache and supports dual-channel DDR4 memory up to 2666 MT/s. The integrated Intel UHD Graphics 630 handles basic display tasks. With 16 PCIe 3.0 lanes, it provides adequate expansion options. The i5-8400T is compatible with LGA 1151 sockets, though it requires 300-series chipsets for official support, offering a balance of efficiency and multi-core capability.
The Intel Core i5-8400T is an 8th Gen Coffee Lake processor designed for low-power desktop builds. With 6 cores and 6 threads, it offers solid multi-tasking. The 'T' suffix means a 35W TDP, allowing for fanless or quiet cooling.
It has a low base clock of 1.7 GHz but boosts up to 3.3 GHz.
It supports DDR4-2666 and includes UHD Graphics 630. Ideal for HTPCs and office setups where noise and power matter more than peak performance.
Specifications
Performance
6 cores handle office tasks easily, though single-core is slower.
Good for 1-2 VMs, but lacks hyper-threading.
Can handle light gaming, but low clocks limit high-refresh gaming.
Outstanding efficiency with a 35W TDP.
- •Low base clock can cause stuttering in CPU-bound games.
- •UHD 630 is only good for very light titles.
- •Best paired with a low-end discrete GPU if gaming.
- •No dedicated AI hardware.
- •Low clocks make inference slow.
Architecture
14nm
Process Node
Coffee Lake
Codename
6C / 6T
Core Config
9 MB
L3 Cache
35 W
TDP
Architecture Overview
The Core i5-8400T is based on the Coffee Lake architecture, which marked the introduction of 6-core designs to the mainstream i5 lineup. Built on the refined 14nm process, it prioritizes power efficiency over raw frequency.
CPU Design
It features 6 physical cores without Hyper-Threading, communicating via a ring bus to the 9 MB L3 Smart Cache. The architecture focuses on delivering multi-core parity with previous generation i7s in a low-power envelope.
Memory Subsystem
The integrated memory controller supports dual-channel DDR4 memory up to 2666 MT/s. This provides sufficient bandwidth for integrated graphics and general CPU tasks.
PCIe & I/O
The processor offers 16 PCIe 3.0 lanes for direct component expansion. This is a step back compared to newer generations, but adequate for a single GPU and NVMe drive.
Overclocking
The 'T' series processors are locked, meaning the multiplier cannot be adjusted. However, the low 35W TDP ensures the chip runs very cool, often allowing it to sustain boost clocks longer in thermally constrained environments.
- Two additional cores (6 vs 4)
- Larger cache (9MB vs 6MB)
- Better multi-threaded performance
Key Highlights
- Extremely low 35W TDP
- 6 cores for parallel tasks
- Runs very cool
- Good for small form factor builds
- Low base and boost clocks
- Locked multiplier
- No Hyper-Threading
- End-of-life platform
History
The Core i5-8400T launched in April 2018 alongside the standard Coffee Lake lineup.</br>It represented a significant shift for low-power desktop computing, offering 6 cores in a 35W envelope, a feature previously reserved for high-end X-series chips.</br>This made it incredibly popular for Small Form Factor (SFF) builders and corporate office deployments.
</br>The processor proved that users didn't have to sacrifice multi-core capability for energy efficiency.</br>While its low base clock of 1.7 GHz raised concerns about single-core performance, its ability to boost to 3.
3 GHz when needed provided adequate responsiveness.</br>It remains a favorite for home server builders looking for a capable yet low-power x86 platform on the used market.
Improvements over Previous Generation
- Two additional cores (6 vs 4)
- Larger cache (9MB vs 6MB)
- Better multi-threaded performance
Alternatives & Competitors
Should You Buy It?
Not Recommended for the right buyer
Building a quiet home server or retro gaming rig on a budget.
Avoid if…
- You need high single-core performance
- You want to play modern AAA games
- You are buying new (better modern alternatives exist)
Use Cases
Interesting Facts
The 'T' suffix denotes a low-power desktop processor, usually 35W.
It was the first generation to offer 6 cores in the Core i5 desktop lineup.
It is compatible with LGA 1151 motherboards, but only 300-series chipsets.
The die size is 154 mm².
It supports DDR4-2666 memory.
The processor includes Intel UHD Graphics 630.
It was launched in April 2018.
Despite the low TDP, it can boost up to 3.3 GHz on a single core.
It is not unlocked for overclocking.
It was popular in small form factor office PCs.
People Also Ask
Is Intel Core i5-8400T good for gaming?
It is okay for light games, but its low clocks limit performance in modern titles.
What is the TDP of the i5-8400T?
35 Watts, making it very power efficient.
Can I overclock the i5-8400T?
No, it is a locked processor.
How many cores does the i5-8400T have?
6 cores and 6 threads.
What socket does the i5-8400T use?
LGA 1151.
What is the max turbo of the i5-8400T?
Up to 3.3 GHz.
Does it have integrated graphics?
Yes, Intel UHD Graphics 630.
What RAM does it support?
DDR4 up to 2666 MT/s.
Is the i5-8400T better than the i5-8400?
The standard 8400 is faster, but the 8400T is more power efficient.
Can it run Windows 11?
Yes, it is officially supported.
Frequently Asked Questions
Is the Core i5-8400T still good in 2024?
It is still usable for office work, but outdated for heavy tasks.
Does it need a dedicated GPU?
No, it has integrated graphics, but a GPU is needed for gaming.
What chipset does it need?
Intel 300-series chipset (e.g., H310, B360).
Can I use it on a 200-series motherboard?
Not officially, it requires 300-series.
Is it good for video editing?
It can handle basic editing, but is slow due to low clocks.
What is the base clock?
1.7 GHz.
Is it good for a home server?
Yes, its 35W TDP makes it excellent for always-on servers.
Does it support Hyper-Threading?
No, it has 6 cores but only 6 threads.
Does it come with a cooler?
Yes, it includes a stock Intel cooler.
What is the max memory?
Up to 128 GB.