Best GPUs for this CPU, bottleneck check, and compatible graphics cards
Core i5-8400 / Intel made / 8th Gen / Released 2018 Also known as: i5-8400 / Corei5-8400
Core i5-8400 (Intel, released in 2018, also listed as i5-8400 / Corei5-8400) is a CPU with a performance score of 10,000, 6C / 6T, TDP 65W. If GPU compatibility and performance balance are poor, a Bottleneck occurs, preventing the GPU or CPU from reaching its full potential. In our estimate, the GPU that pairs best with Core i5-8400 is Radeon RX 6650 XT (estimated bottleneck: about 0%). Below are the top 10 compatible GPUs and a guide to GPUs to avoid.
GPUs are ordered by proximity to the ideal CPU:GPU ratio of 0.9:1. A lower bottleneck percentage means the combination can use more of its performance.
If you want higher graphics settings or plan to keep the PC for years, you can pick a GPU one step stronger. Core i5-8400 will fall slightly behind (a bottleneck of 10% or less), but a later CPU upgrade will let the GPU run at full strength.
The Bottleneck Checker opens with Core i5-8400 already selected.
Core i5-8400 (i5-8400 / Corei5-8400) has a performance score of 10,000 points. Using the same CPU:GPU ≈ 0.9:1 standard as the checker, compatibility by GPU score is shown below.
| GPU Score to Pair | Rating | What It Means |
|---|---|---|
| Below 10,667 points | GPU Too Weak | The GPU is too weak for this CPU. Some of Core i5-8400 performance remains unused (e.g., Intel Arc A580 8GB、GeForce GTX 1660 SUPER、GeForce GTX 1070) |
| 10,667–17,778 points | Great Match: 10% or Less | Optimal balance. Both CPU and GPU can deliver nearly full performance (ideal: about 16,000 pts) |
| 17,778–21,333 points | Acceptable: 10–25% | The GPU is somewhat strong. This is practical, but the CPU may hold it back under heavy load. |
| Over 21,333 points | CPU Bottleneck: Over 25% | The GPU is too powerful for Core i5-8400 to use fully (e.g., GeForce RTX 4060 Ti、GeForce RTX 3070 Ti、Radeon RX 7800 XT、Radeon RX 6800 XT) |
Note: Perceived results vary by resolution and game (GPU matters more at 4K, while CPU matters more at high-fps Full HD). For an exact estimate, use the Bottleneck Checker.
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These CPUs have similar performance scores and may be useful replacement or comparison candidates.
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Our estimate finds that Radeon RX 6650 XT offers the best balance, with an estimated bottleneck of about 0%. A CPU-to-GPU performance ratio near 0.9:1 tends to use both parts effectively. See the top 10 compatible GPUs in the table on this page.
Pairing Core i5-8400 with a powerful GPU scoring over 21,333 points (for example, GeForce RTX 4060 Ti、GeForce RTX 3070 Ti、Radeon RX 7800 XT、Radeon RX 6800 XT) is likely to create a CPU bottleneck above 25%.Conversely, a GPU below 10,667 points（例: Intel Arc A580 8GB、GeForce GTX 1660 SUPER、GeForce GTX 1070） leaves some of Core i5-8400 performance unused.
Core i5-8400 has 6 cores and 6 threads.Its base clock is 2.8GHz and maximum boost clock is 4GHz.The socket is LGA1151.
Core i5-8400 has a TDP of 65W. As a guideline, choose a power supply that covers the CPU TDP plus GPU power draw, with additional headroom.
Its performance score is 10,000 points. CPU–GPU balance matters for games, while core count (6C / 6T) matters for video editing and AI preprocessing. Check the top 10 GPUs above for your use case. GPU VRAM is the main factor for running generative AI, so also see each GPU detail page.
