Rust

Rust is a demanding survival title, and the data for the Intel Core i5-9400 paired with the AMD Radeon RX 7900 XT shows a system that is heavily held back by its processor at lower resolutions, while the GPU takes over at 4K. The measured results indicate that this combination delivers playable frame rates across most settings, but the balance between components shifts dramatically depending on resolution, making the choice of preset critical for a smooth experience.

Resolution Scaling

The frame rate drop from 1080p to 4K is steep but uneven across settings, revealing where the bottleneck lies. At Low settings, the average FPS falls from 140.7 at 1920x1080 to 101.1 at 3840x2160, a reduction of 39.6 FPS. This relatively modest decline suggests that at Low settings, the CPU is still a limiting factor even at 4K, as the GPU is not being pushed to its full capacity. In contrast, at Ultra settings, the average FPS drops from 105.6 at 1080p to 44.7 at 4K, a much larger 60.9 FPS decrease. This steeper curve indicates that at Ultra, the RX 7900 XT becomes the primary constraint, as the higher graphical load scales more directly with pixel count.

The Medium and High presets show intermediate behavior. High settings produce an average of 114.4 FPS at 1080p, falling to 92.4 at 1440p and then 59.0 at 4K. Medium settings yield 123.8 FPS at 1080p, 105.8 at 1440p, and 67.6 at 4K. The pattern is clear: the gap between 1080p and 1440p is smaller than the gap between 1440p and 4K for all presets except Low, where the 1440p result of 124.2 FPS actually exceeds the 1080p Low result of 140.7 by a smaller margin than expected. This suggests that at 1440p and below, the Core i5-9400’s six threads are often the limiting factor, preventing the RX 7900 XT from reaching its full potential. Only at 4K does the GPU’s workload become heavy enough to shift the balance, and even then, the Low preset result of 101.1 FPS indicates the CPU still has influence.

GPU Role

The AMD Radeon RX 7900 XT is a high-end card with 20 GB of GDDR6 memory on a 320-bit bus, providing 800.0 GB/s of bandwidth. Its boost clock of 2394 MHz and game clock of 2025 MHz are substantial, and the 5376 shading units deliver a rated FP32 performance of 51.48 TFLOPS. In Rust, this hardware shows its strength at 4K Ultra, where the average FPS of 44.7 is the lowest measured, indicating the GPU is being fully exercised. However, the card’s 82nd percentile ranking among all GPUs, based on an average benchmark score of 38358, places it well above the Core i5-9400’s 50th percentile ranking among CPUs. This mismatch is reflected in the data: at 1080p Low, the system achieves 140.7 FPS, but the GPU is capable of far more if the CPU could feed it faster.

The VRAM capacity is ample for Rust, even at 4K, where the game’s large maps and texture streaming benefit from the 20 GB buffer. The memory clock of 2500 MHz (20 Gbps effective) supports high bandwidth, which helps at higher resolutions. Yet, the measured FPS at 4K Medium (67.6) and 4K High (59.0) show that the card is not the sole determinant of performance; the CPU still imposes a ceiling in less demanding presets. The GPU’s launch MSRP is 899 USD, but its end-of-life status and the current data suggest it remains a powerful choice for this title, provided the resolution is high enough to leverage its capabilities.

How This Combo Ranks

Among the 1717 tested combinations in the database, this pairing of the Intel Core i5-9400 and AMD Radeon RX 7900 XT ranks 558th for Rust. This places it in the upper third of all combos, but not at the top, reflecting the CPU’s relative weakness. The Core i5-9400 has an average benchmark score of 2305, which is nearly identical to its nearest rivals: the Intel Core i3-10305 (2300, 0.2% delta), the Intel Core i3-1125G4 (2299, 0.2% delta), and the Intel Xeon E-2134 (2295, 0.4% delta). It is only 0.6% behind the Intel Core i7-8809G (2319). This tight clustering means the CPU is performing exactly as expected for its class, offering no surprising headroom.

The GPU, with an average benchmark score of 38358, sits close to the NVIDIA GeForce RTX 5080 Mobile (38349, 0% delta) and the NVIDIA CMP 70HX (38225, 0.3% delta), while being 0.4% ahead of the NVIDIA GeForce MX570 (38494, -0.4% delta) and 0.6% ahead of the NVIDIA GeForce RTX 4080 Mobile (38135). This places the RX 7900 XT in a strong position, but the combo’s overall rank of 558 out of 1717 indicates that other pairings with more balanced CPUs achieve higher performance in Rust. The data suggests that the GPU is being underutilized in many scenarios, particularly at 1080p, where the CPU’s six cores and six threads without hyper-threading become a clear bottleneck.

Measured FPS Breakdown

The measured frames per second data provides a full picture across three resolutions and four settings. At 1920x1080, the Low preset delivers the highest average at 140.7 FPS, followed by Medium at 123.8, High at 114.4, and Ultra at 105.6. The spread from Low to Ultra is 35.1 FPS, indicating that even at the highest settings, the system remains playable, but the CPU limits the maximum output. At 2560x1440, the order changes slightly: Low produces 124.2 FPS, Medium 105.8, High 92.4, and Ultra 70.7. The drop from 1080p to 1440p is most pronounced at Ultra (34.9 FPS) and least at Low (16.5 FPS), reinforcing the idea that the GPU becomes more relevant as settings increase.

At 3840x2160, the averages are significantly lower: Low yields 101.1 FPS, Medium 67.6, High 59.0, and Ultra 44.7. The gap between Low and Ultra at 4K is 56.4 FPS, nearly double the gap at 1080p. This demonstrates that at 4K, the RX 7900 XT’s performance is the dominant factor, and the CPU’s influence wanes. Notably, the 4K Low result of 101.1 FPS is still above 60 FPS, meaning even a heavy resolution with minimal settings is playable. However, the 4K Ultra result of 44.7 FPS falls below the 60 FPS threshold, making it unsuitable for smooth gameplay without adjustments.

Settings Recommendations

For a consistent 60 FPS or higher, the data points to specific presets at each resolution. At 1920x1080, all four settings exceed 100 FPS, so the choice depends on visual preference; Ultra at 105.6 FPS is the best option for quality without sacrificing smoothness. At 2560x1440, Ultra drops to 70.7 FPS, which is still above 60, but Medium at 105.8 FPS offers a more comfortable margin. For players prioritizing frame rate over visuals, Low at 124.2 FPS is the highest, but Medium provides a balanced experience. At 3840x2160, only Low (101.1 FPS) and Medium (67.6 FPS) maintain averages above 60 FPS. High at 59.0 FPS is borderline, and Ultra at 44.7 FPS is not recommended for competitive play. The measured rows suggest that Medium at 4K is the sweet spot, delivering 67.6 FPS while retaining more graphical detail than Low. At 1440p, High at 92.4 FPS offers a strong compromise between visual fidelity and performance, while at 1080p, Ultra is the clear winner.

CPU Role

The Intel Core i5-9400 features six cores and six threads, with a base clock of 2.90 GHz and a boost clock of 4.10 GHz. Its 9 MB of shared L3 cache and 42.7 GB/s memory bandwidth are modest by modern standards, and its 14 nm process node is older than the GPU’s 5 nm node. The CPU’s Cinebench R23 scores are 7969 multi-core and 1125 single-core, placing it at the 50th percentile of all CPUs. In Rust, this processor’s limitations are evident at lower resolutions. At 1080p Low, the system only reaches 140.7 FPS, which is far below what the RX 7900 XT could theoretically deliver. The CPU’s six threads are likely saturated by Rust’s simulation and entity update logic, preventing the GPU from being fully utilized.

The delta to its nearest rivals is minimal—within 0.6%—so there is no hidden performance advantage. The CPU’s end-of-life status and lack of an unlocked multiplier mean there is no overclocking headroom to mitigate the bottleneck. At 4K, the CPU’s role diminishes, as the GPU’s workload increases, but the 4K Low result of 101.1 FPS still suggests the CPU is not entirely idle. The data indicates that this CPU is the primary constraint in most scenarios, and pairing it with a GPU of this caliber creates an imbalance that only high resolutions partially correct.

FAQ

Q: What is the best resolution for this combo in Rust?

A: At 2560x1440 with Medium settings, the average FPS is 105.8, which provides a good balance. At 3840x2160, Medium yields 67.6 FPS, which is above 60, making 4K viable if settings are kept moderate.

Q: Why does the frame rate drop so much from 1080p to 4K at Ultra settings?

A: At Ultra, the average FPS falls from 105.6 at 1920x1080 to 44.7 at 3840x2160. This 60.9 FPS drop reflects the GPU becoming the limiting factor, as the RX 7900 XT’s workload scales heavily with pixel count at high settings.

Q: Is the Core i5-9400 holding back the RX 7900 XT?

A: Yes. At 1080p Low, the average is 140.7 FPS, but the CPU’s six threads limit higher output. The CPU’s 50th percentile ranking versus the GPU’s 82nd percentile shows a clear mismatch, with the CPU being the bottleneck at lower resolutions.

Q: Can this system run Rust at 4K smoothly?

A: Yes, but with caveats. At 4K Medium, the average is 67.6 FPS, and at Low it is 101.1 FPS. Ultra at 44.7 FPS is below the 60 FPS threshold, so High settings at 59.0 FPS are borderline.

Q: How does this combo rank compared to others?

A: It ranks 558th out of 1717 tested combos for Rust. This places it in the upper third, but the CPU’s performance relative to its rivals (within 0.6% delta) means the ranking is driven more by the GPU’s strength.

Q: What settings should I use for the best experience?

A: At 1080p, Ultra at 105.6 FPS is recommended. At 1440p, High at 92.4 FPS offers a good balance. At 4K, Medium at 67.6 FPS is the best choice, as it stays above 60 FPS while retaining more detail than Low.