CPU Comparison
Core i5-6400 vs Intel Core i3-8100
A side-by-side comparison of specs, performance and value. The Intel Core i5-6400 is a 6th generation desktop processor launched in July 2015 as part of the Skylake architecture. Designed for the LGA 1151 socket, it brought the 14nm manufacturing process to the mainstream market. This quad-core processor operates at a base frequency of 2.7 GHz and boosts up to 3.3 GHz. Unlike its predecessor, the 6400 natively supports DDR4 memory alongside DDR3L, offering a transitional platform for motherboard manufacturers. It features 6MB of L3 cache and a modest 65W TDP, making it highly energy efficient for its time. The inclusion of Intel HD Graphics 530 provided competent integrated graphics for non-gaming workloads. While it lacked an unlocked multiplier, it became a favorite for budget builders and system integrators. Its reliable quad-core performance made it a staple in office PCs and budget gaming rigs when paired with a dedicated GPU, serving as a workhorse for years before multi-threading demands outpaced its capabilities.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Sufficient for basic office applications and web browsing, but struggles with heavy multitasking.
The lack of Hyper-Threading severely limits performance in heavily threaded office applications compared to newer 8-thread budget chips.
Gaming
Severely bottlenecks modern GPUs. Only playable in older or very light eSports titles.
Paired with a strong discrete GPU, it can still handle older eSports titles, but modern AAA games will be heavily CPU bottlenecked.
Virtualization
Limited to very light virtualization due to 4 threads.
4 threads is the absolute minimum for running a modern OS and a single light virtual machine.
Efficiency
Efficient for its time, but superseded by modern 10nm/Intel 7 processes.
The 14nm process is power-hungry compared to modern 7nm or 5nm alternatives, drawing 65W for modest performance.
Specialized Performance
AI / ML
- No AI acceleration
- Insufficient threads for modern AI workloads
- No AI hardware acceleration
- Lacks AVX-512
- Far too slow for any practical AI inference
Content Creation
Gaming
- Low base clock limits frame rates
- 4 cores cause stuttering in modern games
- Acceptable only for retro gaming
- Requires a dedicated GPU for any gaming
- Fixed clock speed prevents single-thread boosts
- 4 cores are becoming the bare minimum for modern games
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Low 65W TDP for easy cooling
- Supports both DDR4 and DDR3L memory
- Solid single-core performance for its generation
- Includes HD Graphics 530 for display tasks
Cons
- Only 4 cores and 4 threads
- Low base clock of 2.7 GHz
- Locked multiplier prevents overclocking
- Not supported by Windows 11
Pros
- Historically significant for bringing 4 cores to the i3 tier
- Very cheap on the used market
- Low 65W TDP is easy to cool
- UHD 630 iGPU is sufficient for basic display tasks
- Stable, mature platform with abundant used motherboards
Cons
- No Hyper-Threading (4 cores, 4 threads only)
- No Turbo Boost (fixed 3.6 GHz clock)
- DDR4 memory speed artificially capped at 2400 MT/s
- Outdated 14nm architecture with poor efficiency
- Limited to PCIe 3.0
Competitors & Alternatives
Core i5-6400
- AMD FX-8350Rival
Desktop
- Compare head-to-headIntel Core i5-6500Rival
Desktop
- AMD FX-6300Rival
Desktop
- Intel Core i3-6100Rival
Desktop
- AMD Ryzen 5 1400Rival
Desktop
Vastly better performance and platform for a similar budget.
Compare head-to-head- AMD Ryzen 5 3600Alt
More cores and threads for better multi-threaded workloads.
Slight performance bump on the same socket if upgrading cheaply.
Compare head-to-headHyper-threading on the same socket for better multi-core performance.
Compare head-to-head- AMD Ryzen 5 2600Alt
Modern alternative with more threads and better upgrade path.
Intel Core i3-8100
- AMD Ryzen 3 1200Rival
Budget Desktop
- AMD Ryzen 3 2200GRival
Budget Desktop APU
- Intel Pentium Gold G5400Rival
Entry Desktop
- AMD Ryzen 5 1400Rival
Mid-Range Desktop
- Compare head-to-headIntel Core i5-7400Rival
Previous Gen Mid-Range
A drop-in replacement (with a BIOS update) that adds Hyper-Threading for 8 threads and much higher clocks.
Compare head-to-head- AMD Ryzen 3 3100Alt
Offers SMT (8 threads) and a modern upgrade path to Ryzen 5000 series.
If staying on the exact same platform, the 8400 offers 6 cores for much better multitasking.
Compare head-to-head- AMD Ryzen 5 3600Alt
A massively faster 12-thread CPU that redefines budget performance.
The current king of budget computing, offering IPC gains that make the 8100 look stationary.
Compare head-to-head
Our Verdict on Each
The Core i5-6400 was a fantastic budget CPU in 2015, but its 4-core/4-thread design and low clock speeds make it heavily outdated for modern gaming and productivity.
Best for: Building a retro gaming PC or basic office machine from used parts
Read the full reviewA landmark chip in 2017 for bringing quad-core computing to the masses, but thoroughly outclassed by modern budget processors in every metric.
Best for: The only justifiable scenario for purchasing an Intel Core i3-8100 today is if you are repairing an existing LGA 1151 v2 system (like an office PC or a hand-me-down) and can find the CPU for under $20 on the used market. Even then, you must consider that the 8100 lacks Hyper-Threading, which severely limits its longevity in modern operating systems that are increasingly optimized for 8 or more threads. If you are building a new system, even the absolute cheapest new motherboard and CPU combo from AMD or Intel's 12th/13th gen will offer exponentially better performance, efficiency, and platform features like PCIe 4.0 or DDR5. Do not buy this CPU for gaming, as the lack of Turbo Boost and Hyper-Threading will cause severe stuttering in modern titles compared to a modern Ryzen 3.
Read the full reviewFrequently Asked Questions
Which is better, Core i5-6400 or Intel Core i3-8100?
Based on our editorial ratings, the Core i5-6400 comes out ahead with a score of 6/10. 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, Core i5-6400 or Intel Core i3-8100?
For gaming, the Intel Core i3-8100 leads with a gaming performance score of 30/100 among Core i5-6400 and Intel Core i3-8100.
Do Core i5-6400 and Intel Core i3-8100 use the same socket?
Yes — all of these CPUs use the LGA 1151 socket, so they share compatible motherboards.