Rust

The Intel Core i5-9400 paired with the NVIDIA GeForce RTX 4080 SUPER presents a distinct bottleneck scenario in Rust. The data shows this is a 1080p and 1440p-focused combination, where the GPU’s immense power is partially held back by the six-core processor. At 4K, the scales tip heavily in the GPU’s favor, delivering playable frame rates even on High settings. The measured results indicate that for smooth, competitive play, the Medium preset offers the best balance of visual fidelity and performance, while Low is the choice for maximum frame rates.

Settings Recommendations

The benchmark data shows a clear pattern across resolutions: the Ultra preset demands too much from this CPU-GPU pairing, resulting in the lowest average frame rates. At 1920x1080, Ultra yields 102.6 FPS, which is respectable but leaves performance on the table. The Medium preset at this resolution produces 122.1 FPS, a 19% increase over Ultra, while High sits at 116.5 FPS. For 1080p gamers, Medium is the sweet spot—it provides a significant frame rate boost over Ultra without the visual downgrade of Low, which hits 141 FPS but may compromise visibility in a survival game where spotting distant players is critical.

Moving to 2560x1440, the pattern shifts. High produces 102.8 FPS, Medium hits 111 FPS, and Ultra drops to 87.8 FPS. Low reaches 126.5 FPS. Here, Medium remains the most balanced choice, offering the best combination of frame rate and graphical quality. The 4K results are the most telling: 3840x2160 High delivers 66 FPS, Medium 80.9 FPS, Low 107.5 FPS, and Ultra falls to 52.9 FPS. At this resolution, the GPU is heavily utilized, and the CPU bottleneck lessens. For 4K, Medium is again the recommended preset—it keeps the frame rate above 60 FPS while maintaining a playable visual standard. Low is viable for those prioritizing smoothness above all, especially in large player-built bases where frame dips are common.

How This Combo Ranks

This specific configuration ranks 451st out of 1717 tested combos in Rust. That places it in the top 26% of all systems tested, a strong showing but not a top-tier result. The ranking reflects the imbalance: the RTX 4080 SUPER is an elite GPU, sitting in the 88th percentile of all GPUs, but the Core i5-9400 is a mid-range processor from 2018, sitting in the 50th percentile of all CPUs. The data indicates that the CPU is the limiting factor in this pairing, particularly at lower resolutions where the processor must feed frames to the GPU faster. The combo’s rank suggests that while the system is capable of high frame rates, it does not fully exploit the GPU’s potential in CPU-bound scenarios. For comparison, the GPU’s average benchmark score of 53610 puts it just 0.2% ahead of the AMD Radeon RX 6900 XT and 2.9% ahead of the NVIDIA GeForce RTX 5070 Ti, but those rivals would likely rank higher when paired with a stronger processor.

GPU Role

The RTX 4080 SUPER is the dominant component in this build, and its specifications explain the 4K capability. With 16 GB of GDDR6X memory on a 256-bit bus, bandwidth reaches 736.3 GB/s. This is sufficient for Rust’s large, detailed maps and high-resolution textures at 4K. The GPU’s boost clock of 2550 MHz and 10240 shading units provide the raw compute needed for the game’s draw calls and lighting. The 52.22 TFLOPS of FP32 performance ensures that even at 3840x2160, the GPU is not the primary constraint. The measured data confirms this: at 4K Ultra, the frame rate drops to 52.9 FPS, but this is likely due to the CPU struggling to issue draw calls, not the GPU lacking fill rate. The GPU’s 80 RT cores and 320 Tensor cores are present, though Rust does not heavily utilize ray tracing, so their impact is minimal. The 88th percentile GPU ranking indicates that this card is far above average, and in this pairing, it is the component that guarantees playability at high resolutions.

Measured FPS Breakdown

At 1920x1080, the lowest resolution tested, the data shows the CPU bottleneck clearly. Low settings produce 141 FPS, Medium 122.1 FPS, High 116.5 FPS, and Ultra 102.6 FPS. The spread from Low to Ultra is 38.4 FPS, a 27% difference. This indicates that as settings increase, the workload shifts, but the CPU’s six cores and six threads at a 4.10 GHz boost clock struggle to maintain higher frame rates. The difference between Medium and High is small (5.6 FPS), suggesting that the GPU is still capable but the CPU is nearing its limit.

At 2560x1440, the pattern changes. Low produces 126.5 FPS, Medium 111 FPS, High 102.8 FPS, and Ultra 87.8 FPS. The gap between Low and Ultra narrows to 38.7 FPS, but the absolute values are lower, indicating that the GPU is now taking on more work. The 1440p High result of 102.8 FPS is close to the 1080p High result of 116.5 FPS, showing a 12% drop from the resolution increase, which is reasonable.

At 3840x2160, the CPU bottleneck is largely alleviated. Low hits 107.5 FPS, Medium 80.9 FPS, High 66 FPS, and Ultra 52.9 FPS. The difference between Low and Ultra is 54.6 FPS, a 51% spread, which is larger than at lower resolutions. This is because the GPU is now the primary driver, and each settings tier significantly impacts fill rate. The 4K High result of 66 FPS is above the 60 FPS threshold for smooth play, while Ultra dips below it. The 4K Low result of 107.5 FPS is impressive, showing that the GPU alone can handle high frame rates even at 4K when the CPU is not the bottleneck.

FAQ

Q: Is the RTX 4080 SUPER wasted on the i5-9400 in Rust?

A: At 1080p and 1440p, partially yes. The data shows the CPU limits frame rates, with 1080p Low hitting 141 FPS but 1080p Ultra only reaching 102.6 FPS. At 4K, the GPU is fully utilized, with High hitting 66 FPS, so it is not wasted at that resolution.

Q: What is the best settings preset for competitive play?

A: The Medium preset offers the best balance. At 1080p it delivers 122.1 FPS, at 1440p it hits 111 FPS, and at 4K it maintains 80.9 FPS. These are all well above the 60 FPS threshold, with better visuals than Low.

Q: Can this combo handle 4K gaming in Rust?

A: Yes, but not on Ultra. The measured data shows 4K High at 66 FPS and 4K Medium at 80.9 FPS. Ultra drops to 52.9 FPS, which is below the smoothness threshold for fast-paced gameplay.

Q: How does the CPU affect performance at different resolutions?

A: The bottleneck is most severe at 1080p, where the CPU must prepare frames faster than it can, capping performance. As resolution increases, the GPU takes on more work, and the 4K results show less CPU limitation, with Low hitting 107.5 FPS.

Q: Is the i5-9400’s 6-core/6-thread configuration sufficient for Rust?

A: Benchmark results indicate it is adequate but not ideal. The CPU’s 50th percentile ranking shows it is average, and the data shows frame rate drops at high settings due to thread limitations. Upgrading the CPU would likely improve 1080p performance significantly.

CPU Role

The Intel Core i5-9400 is a 6-core, 6-thread processor from the Coffee Lake Refresh generation, based on a 14 nm process. Its base clock is 2.90 GHz, with a boost clock of 4.10 GHz. The CPU has 9 MB of shared L3 cache and supports dual-channel DDR4 memory with a bandwidth of 42.7 GB/s. These specifications place it in the 50th percentile of all CPUs, with an average benchmark score of 2305. In Rust, which is known to be CPU-intensive, this processor’s performance is the limiting factor in this pairing.

The measured FPS data shows that at 1080p, the CPU is the primary constraint. The difference between Low and High settings at 1080p is only 24.5 FPS, suggesting that the GPU is not the bottleneck; instead, the CPU’s ability to process game logic and draw calls caps the frame rate. The single-core performance, as measured by Cinebench R23 at 1125, is crucial for Rust’s main thread, which handles most of the game’s simulation. The multi-core score of 7969 indicates that the CPU can handle some parallel tasks, but with only 6 threads, it struggles when many entities are on screen. The nearest rival, the Intel Core i3-10305, is only 0.2% faster, showing that this CPU is at the edge of its performance class. For this combo, the CPU dictates that Ultra settings are not viable at any resolution, as the 1080p Ultra frame rate of 102.6 FPS is only slightly higher than the 4K High result of 66 FPS, proving the CPU is the ceiling.