CPU Comparison
Intel Core i5-8400T vs Intel Core i5-8420T
A side-by-side comparison of specs, performance and value. 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 Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
6 cores handle office tasks easily, though single-core is slower.
6 cores provide good office performance, but single-core is limited.
Gaming
Can handle light gaming, but low clocks limit high-refresh gaming.
Marginally better than 8400T, but still too slow for modern gaming.
Virtualization
Good for 1-2 VMs, but lacks hyper-threading.
Suitable for basic VMs, but lacks threads.
Efficiency
Outstanding efficiency with a 35W TDP.
Excellent 35W efficiency.
Specialized Performance
AI / ML
- No dedicated AI hardware.
- Low clocks make inference slow.
- No dedicated AI hardware.
- Slow CPU inference.
Content Creation
Gaming
- 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.
- Low clocks limit high-refresh gaming.
- Integrated graphics are weak.
- Needs a discrete GPU for any real gaming.
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Extremely low 35W TDP
- 6 cores for parallel tasks
- Runs very cool
- Good for small form factor builds
Cons
- Low base and boost clocks
- Locked multiplier
- No Hyper-Threading
- End-of-life platform
Pros
- Low 35W TDP
- 6 cores for multi-tasking
- Runs cool and quiet
- Good for basic office use
Cons
- Very similar to 8400T
- Locked multiplier
- No Hyper-Threading
- Hard to find retail, OEM only
Competitors & Alternatives
Intel Core i5-8400T
- AMD Ryzen 5 2400GERival
Low Power Desktop
- Compare head-to-headIntel Core i5-8400Rival
Mainstream Desktop
- AMD Ryzen 5 2600ERival
Low Power Desktop
- Compare head-to-headIntel Core i5-7400TRival
Previous Gen Low Power
- AMD Ryzen 3 2200GERival
Budget Low Power
Slightly faster clocks, same TDP.
Compare head-to-head- AMD Ryzen 5 3400GEAlt
Better integrated graphics.
Much faster modern architecture.
Compare head-to-head- AMD Ryzen 5 5600GEAlt
Better efficiency and performance.
Slightly higher clocks if buying used.
Compare head-to-head
Intel Core i5-8420T
- Compare head-to-headIntel Core i5-8400TRival
Low Power Desktop
- AMD Ryzen 5 2400GERival
Low Power Desktop
- Compare head-to-headIntel Core i5-8500TRival
Low Power Desktop
- AMD Ryzen 3 2200GERival
Budget Low Power
- Compare head-to-headIntel Core i3-8100TRival
Budget Low Power
- AMD Ryzen 5 3400GEAlt
Better integrated graphics.
Modern alternative with much better IPC.
Compare head-to-head- AMD Ryzen 5 5600GEAlt
Better efficiency and multi-core.
Our Verdict on Each
A highly efficient 6-core processor perfect for compact builds, though its low clock speeds limit performance compared to the standard 8400.
Best for: Building a quiet home server or retro gaming rig on a budget.
Read the full reviewA modest refresh of the 8400T, offering slightly higher clocks in the same 35W envelope, primarily for OEM systems.
Best for: Finding a cheap used OEM PC with this chip for basic office work.
Read the full reviewFrequently Asked Questions
Which is better, Intel Core i5-8400T or Intel Core i5-8420T?
Based on our editorial ratings, the Intel Core i5-8400T comes out ahead with a score of 7.5/10. That said, the best choice depends on your workload — check the spec and performance breakdown above for gaming, productivity and efficiency differences.
Which is faster for gaming, Intel Core i5-8400T or Intel Core i5-8420T?
For gaming, the Intel Core i5-8420T leads with a gaming performance score of 52/100 among Intel Core i5-8400T and Intel Core i5-8420T.
Do Intel Core i5-8400T and Intel Core i5-8420T use the same socket?
Yes — all of these CPUs use the LGA 1151 socket, so they share compatible motherboards.
Which is faster in multi-core benchmarks?
The Intel Core i5-8420T posts the highest multi-core benchmark score. Multi-core results: Intel Core i5-8400T (8,500), Intel Core i5-8420T (8,600). Benchmark figures are approximate and workload-dependent.