Rust

The pairing of an Intel Core i5-9400 with an NVIDIA GeForce RTX 4090 in Rust presents a study in extremes, where a six-core CPU from 2018 meets the flagship Ada Lovelace GPU from 2022. The benchmark data reveals a configuration that is heavily skewed by processor limitations at lower resolutions, yet still manages to deliver playable frame rates at 4K thanks to the sheer horsepower of the graphics card. This analysis interprets the measured FPS rows to explain how the GPU and CPU each shape the experience, and where this specific combination stands among thousands of tested systems.

Settings Recommendations

The measured data for this combination in Rust shows a clear pattern where the Low preset consistently delivers the highest average frame rates across all tested resolutions, making it the best choice for players prioritizing maximum smoothness. At 1920x1080, the Low preset achieves 142 FPS, which is 20 FPS higher than the next best option, High, at 115 FPS. This gap suggests that the Low settings reduce the processing load enough for the CPU to push more frames, even though the RTX 4090 is capable of far more. For competitive play or environments with heavy player-built structures, this preset offers the most headroom.

However, the Medium preset provides a more balanced experience, particularly for those who want better visual fidelity without a dramatic performance penalty. The data shows Medium at 1080p yields 122 FPS, which is only a 20 FPS drop from Low but a 7 FPS improvement over High. More importantly, the Medium preset is the only one at every resolution that includes both minimum and maximum FPS values, with a spread from 104 to 140 at 1080p, indicating more consistent frame pacing than the other presets which lack these data points. At 2560x1440, Medium holds 108 FPS (with a 92-124 FPS range), and at 3840x2160 it maintains 87 FPS (with a 74-100 FPS range), making it the most reliable option for a stable experience across all resolutions. The High preset is a middle ground, showing 115 FPS at 1080p and 101 FPS at 1440p, but it falls to 73 FPS at 4K, which is borderline for smooth gameplay. The Ultra preset is the most demanding, yielding only 104 FPS at 1080p and dropping to 56 FPS at 4K, which is not ideal for a fast-paced survival game. Given the data, the Medium preset appears to be the optimal choice for balancing visual quality with the most consistent frame delivery, while Low is the go-to for maximizing raw FPS.

GPU Role

The NVIDIA GeForce RTX 4090 is an absolute powerhouse, and its specifications in the FACT PACK explain why it can brute-force Rust to high frame rates even when paired with a weaker CPU. The GPU features 24 GB of GDDR6X memory on a 384-bit bus, delivering a massive 1.01 TB/s of bandwidth. For Rust, which is known for its large, player-modified worlds and many assets, this large memory pool is likely preventing any texture streaming bottlenecks, allowing the game to load and render the environment without stuttering. The GPU's architecture, Ada Lovelace, includes 16,384 shading units and 128 RT cores, with a boost clock of 2520 MHz, providing an immense amount of raw compute power. This is reflected in its Passmark G3D score of 38194 and an average benchmark score of 60347, placing it in the 88th percentile of all GPUs. The data suggests that the RTX 4090 is never the primary limiting factor in Rust; even at 4K Ultra, the frame rate is more likely constrained by the CPU's ability to issue draw calls than by the GPU's rendering capacity.

The GPU's relative performance against its nearest rivals, such as the Intel Arc Pro A60 and AMD Radeon Pro Vega 48, shows a nearly identical average score (0% delta), which is curious but irrelevant to game-specific performance. In Rust, the RTX 4090's role is to ensure that the framerate is as high as the CPU allows, effectively waiting for the processor to catch up at lower resolutions. This is evident in the FPS data, where the difference between 1080p and 4K is not as large as one might expect from a GPU-centric bottleneck, indicating that the GPU is not being fully utilized at 1080p.

Resolution Scaling

The measured FPS data shows a clear trend of decreasing performance as resolution increases, but the rate of decrease is more moderate than expected for a GPU-bound scenario. From 1920x1080 to 2560x1440, the average FPS drops from 142 to 125 on the Low preset, a 12% reduction. Then, moving from 2560x1440 to 3840x2160, the FPS drops from 125 to 105, another 16% reduction. This pattern suggests that while the GPU is taking on more work at higher resolutions, the CPU is still the primary bottleneck at 1080p, preventing the FPS from being much higher. For the Medium preset, the scaling is similar: 122 FPS at 1080p, 108 FPS at 1440p, and 87 FPS at 4K. The most dramatic drop is seen in the High preset, which falls from 115 FPS at 1080p to 101 FPS at 1440p (a 12% drop) and then to 73 FPS at 4K (a 28% drop from 1440p). This steeper decline at 4K for High settings indicates that the GPU is finally becoming more of a limiting factor, but the RTX 4090 still manages to keep the frame rate playable.

The implication of this scaling is that the Intel Core i5-9400 is holding back the system significantly at 1080p and 1440p. In a balanced system, the RTX 4090 would typically show a much larger gap between 1080p and 4K, as the GPU load increases quadratically with pixel count. Here, the modest 26% total drop from 142 FPS to 105 FPS on Low settings across the three resolutions confirms that the CPU is the bottleneck at lower resolutions, and the GPU only starts to feel the strain at 4K. This means that players with this combo who have high-refresh-rate 1080p monitors will not see the full potential of the RTX 4090; the CPU will cap the maximum frame rate.

How This Combo Ranks

In the database of tested combinations, this specific pairing of the Intel Core i5-9400 and the NVIDIA GeForce RTX 4090 holds a rank of 947 out of 3723 combos for Rust. This places it in the top 25% of all tested systems, which is a strong showing, but it is not a top-tier ranking. The rank reflects the actual measured performance of this specific pair, and given the CPU's age, it is impressive that the combo still performs this well. The rank suggests that while the RTX 4090 is providing a significant boost, the Intel Core i5-9400 is dragging the overall score down relative to other systems that pair this GPU with a more modern processor. For example, a system with a newer, higher-core-count CPU would likely rank much higher, as the CPU bottleneck would be alleviated.

The CPU's own benchmark percentile is only 47, meaning that it is slower than 53% of all CPUs in the database. This is a clear indicator of its limitations. When combined with a top-tier GPU like the RTX 4090, the mismatched pairing results in a rank that is good but not exceptional. It reflects the RTX 4090's power that it can still push this combo into the top quarter of all systems, but the data suggests that upgrading the CPU would yield substantial gains in Rust. The combo rank is a holistic score, and it shows that the whole is greater than the sum of its parts, but the parts are not balanced.

FAQ

Q: What is the best preset for this combo at 1080p?

A: The Low preset offers the highest average FPS at 1920x1080, with a score of 142 FPS, making it the best for maximum performance. The Medium preset is a strong alternative, providing a more stable experience with a 104-140 FPS range.

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

A: Yes, the data shows it can. At 3840x2160 with Medium settings, the combo achieves an average of 87 FPS with a 74-100 FPS range, which is smooth. Even on High settings, it maintains 73 FPS on average, which is still playable.

Q: Is the RTX 4090 being fully utilized in this system?

A: No, the benchmark results indicate that the Intel Core i5-9400 is the primary bottleneck. The FPS drop from 1080p to 4K is relatively small for the GPU's power, suggesting the GPU is waiting on the CPU at lower resolutions.

Q: How does the i5-9400 compare to its nearest rivals?

A: The Intel Core i7-1068NG7 is 0.2% slower, while the Intel Core i7-10710U is 0.3% faster, and the AMD Ryzen 5 PRO 1500 is 0.4% faster. These differences are minimal, indicating the i5-9400 is competitively positioned among its immediate peers.

Q: What is the launch MSRP of the RTX 4090?

A: The launch MSRP of the NVIDIA GeForce RTX 4090 is 1,599 USD.

Q: Is the Medium preset more stable than others?

A: Yes, the data includes minimum and maximum FPS values only for the Medium preset across all resolutions. For example, at 1080p, it has a 104-140 FPS range, suggesting more consistent frame delivery.

Measured FPS Breakdown

The following is the exact measured average FPS data for this combination in Rust, organized by resolution and settings.

1920x1080:

• Low: 142 FPS average
• Medium: 122 FPS average (minimum 104 FPS, maximum 140 FPS)
• High: 115 FPS average
• Ultra: 104 FPS average

2560x1440:

• Low: 125 FPS average
• Medium: 108 FPS average (minimum 92 FPS, maximum 124 FPS)
• High: 101 FPS average
• Ultra: 92 FPS average

3840x2160:

• Low: 105 FPS average
• Medium: 87 FPS average (minimum 74 FPS, maximum 100 FPS)
• High: 73 FPS average
• Ultra: 56 FPS average

This data shows a consistent hierarchy across all resolutions, with Low being the fastest and Ultra being the slowest. The performance gap between Low and Ultra is 38 FPS at 1080p, 33 FPS at 1440p, and 49 FPS at 4K, highlighting that the Ultra preset becomes disproportionately more demanding at higher resolutions.

CPU Role

The Intel Core i5-9400 is a 6-core, 6-thread processor based on the Coffee Lake architecture, with a base clock of 2.90 GHz and a boost clock of 4.10 GHz. Its 9 MB of shared L3 cache and dual-channel DDR4 memory support are standard for its generation. In the context of Rust, this CPU's role is critical, as the game is known to be heavily dependent on single-core performance and CPU frequency for handling the complex simulation of player interactions, building physics, and the server-side tick rate. The data indicates that this CPU is the primary bottleneck for this combo. Its Cinebench R23 multicore score of 6629 and single-core score of 935 show it is a modest performer by modern standards, and its 47th percentile ranking against all CPUs confirms its relative weakness.

The CPU's performance against its nearest rivals is tightly clustered, with a delta of -0.2% to the Intel Core i7-1068NG7 and +0.3% to the Intel Core i7-10710U, showing it is not an outlier in either direction. However, its 6 threads are a limitation in modern games that can utilize more. In Rust, the benchmark results show that at 1080p with Low settings, the FPS is capped at 142, which is likely near the CPU's limit for generating frames. As the resolution increases, the FPS drops, but the rate of drop is slower than expected, further confirming that the CPU's frame generation capability is the limiting factor. The boost clock of 4.10 GHz is decent, but the aging architecture means it cannot feed the RTX 4090 enough data to reach its full potential, particularly in high-player-count or base-heavy scenarios. This pairing demonstrates that while a powerful GPU can rescue a system, the CPU ultimately dictates the ceiling on performance in CPU-intensive titles like Rust.