Performance comparison: which is faster?
Core i3-11100 (Intel, 2021) and Core i5-8400 (Intel, 2018) are compared here. Compare not only scores, but also whether the motherboard can be reused and which GPU class is balanced with each CPU.
Overall performance: i3-11100 is about 5% faster
The sockets differ (LGA1200 / LGA1151), so switching requires a motherboard replacement. For games, performance balance with the GPU (guideline CPU:GPU = 0.9:1) matters more than CPU speed alone.
Relative performance score (higher is faster). Actual speed varies by workload, cooling, and memory configuration.
| Item | i3-11100 | i5-8400 |
|---|---|---|
| Performance Score | 10,500 | 10,000 |
| Generation | 11th Gen | 8th Gen |
| Socket | LGA1200 | LGA1151 |
| Release Year | 2021 | 2018 |
| Type | Desktop | Desktop |
| Compatible GPU Example | GeForce RTX 4060 | Radeon RX 6650 XT |
| If You Want To... | Recommended |
|---|---|
| Prioritize maximum speed for heavy work or a high-end GPU | i3-11100 |
| Upgrade while reusing the current motherboard | Choose the CPU matching your motherboard socket |
| Prioritize value and adequate performance | i5-8400 (the lower model is often sufficient) |
i3-11100 is about 5% higher by score (i3-11100: 10500 points / i5-8400: 10000 points). For gaming, the GPU tier usually matters more than a few percent of CPU difference. For CPU-heavy work such as video editing and streaming, choose the faster CPU.
i3-11100 is 11th Gen, while i5-8400 is 8th Gen.The sockets differ (LGA1200 / LGA1151), so switching requires a motherboard replacement.
Using our CPU:GPU = 0.9:1 guideline, GeForce RTX 4060 pairs well with i3-11100 and Radeon RX 6650 XT pairs well with i5-8400. If either GPU is too strong or too weak, one part holds the other back.
