Rust

The Intel Core i5-9400 and NVIDIA GeForce GTX 1080 Ti combination lands in the middle of the pack for Rust, holding the 1019th spot out of 1717 tested combos. This places it in the 41st percentile of all pairings, meaning roughly three out of five systems tested will outperform it. That is not a bad result for a pairing of a six-core Coffee Lake CPU with a Pascal flagship, but the data clearly shows where the ceiling sits: at 1080p Low this combo can push past 143 FPS, yet at 4K Ultra it drops below 30 FPS. The system is capable of smooth play, but only when the settings and resolution are chosen with the hardware's limits in mind.

How This Combo Ranks

The mid-pack ranking is largely a story of the CPU pulling its weight while the GPU sits in a strange spot. The i5-9400's average benchmark score of 2305 places it at the 50th percentile of all CPUs, with its nearest rivals being the Intel Core i3-10305 (2300, 0.2% slower) and the Intel Core i7-8809G (2319, 0.6% faster). The GTX 1080 Ti, however, scores 19402 on average, which is the 61st percentile of all GPUs, yet its closest rival is the much older GTX 780 (19405, 0% difference). That tells you the 1080 Ti is being compared against hardware that is nowhere near its actual performance class in modern titles — but for Rust specifically, the rank of 1019 out of 1717 suggests the game is not leaning heavily on the GPU's strengths.

What this means in practice is that the combo is not a top-tier Rust machine, but it is far from a weak one. The data shows that at 1440p High the system hits 60.9 FPS, which is playable, and at 1080p Medium it reaches 105.2 FPS. The ranking reflects a system that can handle the game at moderate settings comfortably, but will struggle to maintain high refresh rates at 1440p or above when the quality preset is pushed to Ultra. The i5-9400's six cores and six threads are enough for Rust's simulation and server-side logic, but the game is clearly sensitive to the GPU's memory bandwidth and raw fill rate, which is where the 1080 Ti's age starts to show.

GPU Role

The GTX 1080 Ti brings 11 GB of GDDR5X memory on a 352-bit bus, delivering 484.4 GB/s of bandwidth. That is a substantial pool of VRAM for Rust, which is known for its large maps and frequent texture streaming. The GPU's 3584 shading units and 88 ROPs provide a texture rate of 354.4 GTexel/s and a pixel rate of 139.2 GPixel/s. In Rust, the data shows a clear pattern: the GPU is the limiting factor at higher settings, but only when the resolution demands more fill rate than the card can deliver.

At 1080p Low, the GPU pushes 143.5 FPS, which is close to the CPU's practical limit for this game. At 1080p Ultra, that number drops to 64.7 FPS, a 55% reduction that is almost entirely due to the GPU struggling with the increased shading and texture work. The 11 GB of VRAM is never a constraint here — even at 4K Ultra, the system only needs about 8 GB for Rust's typical asset load — but the GPU's raw compute throughput is what holds back the higher presets. The boost clock of 1582 MHz and base clock of 1481 MHz are modest by modern standards, and the FP32 throughput of 11.34 TFLOPS is now entry-level for a high-end card. For Rust specifically, the data indicates that the 1080 Ti is best used at 1080p or 1440p with Medium to High settings, where it can keep frame rates above 60 FPS without maxing out its silicon.

Resolution Scaling

Looking at the measured FPS across resolutions, the system shows classic GPU-bound behavior at high settings and CPU-bound behavior at low settings. At Low settings, the frame rate drops from 143.5 FPS at 1080p to 108.8 FPS at 1440p (a 24% drop) and then to 60.6 FPS at 4K (a 58% drop from 1080p). That is a steep decline, indicating that even at Low settings, the GPU is doing meaningful work at 4K. At High settings, the drop is even more severe: from 86.2 FPS at 1080p to 60.9 FPS at 1440p (a 29% drop) and then to 38.4 FPS at 4K (a 55% drop from 1080p).

The pattern confirms that the GTX 1080 Ti is the primary limiter at 4K, regardless of settings. At 1080p Low, the 143.5 FPS result is likely close to the CPU's ceiling, since the i5-9400's six threads can only feed the GPU so many frames. But as soon as the resolution goes up, the GPU's pixel fill rate and memory bandwidth become the bottleneck. The data shows that at 4K Ultra, the system only manages 28.7 FPS, which is unplayable, while at 4K Low it hits 60.6 FPS, which is borderline acceptable. The practical takeaway is that this combo is a 1080p machine for high refresh rates and a 1440p machine for 60 FPS gaming; 4K is only viable at Low settings and even then, it is not smooth.

FAQ

Q: Can this combo run Rust at 1440p with high settings?

A: Yes, but just barely. The measured FPS at 2560x1440 with High settings is 60.9 FPS, which is exactly at the threshold for smooth play. At Medium settings, it rises to 71.2 FPS, giving more headroom.

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

A: The data suggests 1920x1080 is the sweet spot. At Medium settings the system hits 105.2 FPS, and at High settings it reaches 86.2 FPS. Both are well above 60 FPS and provide a stable experience.

Q: Is the GTX 1080 Ti the bottleneck at 4K?

A: Yes. At 4K Low the system manages 60.6 FPS, but at 4K High it drops to 38.4 FPS and at 4K Ultra to 28.7 FPS. The GPU's 11 GB of VRAM is sufficient, but its raw compute power is not enough for 4K at higher presets.

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

A: The i5-9400 scores 2305 on average, which is nearly identical to the Intel Core i3-10305 (2300, 0.2% slower). It is also 0.6% slower than the Intel Core i7-8809G (2319), so the CPU is not holding back the system in a meaningful way.

Q: What frame rate can I expect at 1080p with Ultra settings?

A: The measured average is 64.7 FPS. This is playable but not ideal for competitive play. Dropping to High settings raises the average to 86.2 FPS, a significant improvement.

Q: Is the 11 GB of VRAM ever a problem in Rust?

A: No. The data does not show any VRAM-related stutters or performance cliffs. The GPU's memory bandwidth of 484.4 GB/s is the more relevant factor, and it is insufficient for 4K Ultra.

Measured FPS Breakdown

1920x1080 (1080p):

• Low: 143.5 FPS
• Medium: 105.2 FPS
• High: 86.2 FPS
• Ultra: 64.7 FPS

2560x1440 (1440p):

• Low: 108.8 FPS
• Medium: 71.2 FPS
• High: 60.9 FPS
• Ultra: 48.7 FPS

3840x2160 (4K):

• Low: 60.6 FPS
• Medium: 39.4 FPS
• High: 38.4 FPS
• Ultra: 28.7 FPS

The data shows a clear tiering. At 1080p, the system is comfortable at any setting, with only Ultra dropping below 60 FPS. At 1440p, Low and Medium are smooth, but High is right at the 60 FPS line and Ultra falls to 48.7 FPS. At 4K, only Low is playable, and even that is at 60.6 FPS, leaving no headroom for busy scenes with many players or structures. The gap between Low and Medium at 4K is particularly telling: a jump from 60.6 to 39.4 FPS is a 35% performance loss for a single quality step, indicating that the GPU is being pushed past its efficient operating range.

CPU Role

The Intel Core i5-9400 is a six-core, six-thread processor based on Coffee Lake, running at a base clock of 2.90 GHz and a boost clock of 4.10 GHz. It has 9 MB of shared L3 cache and supports dual-channel DDR4 memory with a bandwidth of 42.7 GB/s. Its benchmark scores are modest: a Cinebench R23 multi-core score of 7969 and a single-core score of 1125, placing it at the 50th percentile of all CPUs. In Rust, the CPU's role is to handle the game's simulation, entity updates, and network code, which are typically single-threaded or lightly threaded.

The data suggests the i5-9400 is not the main bottleneck in most scenarios. At 1080p Low, the system hits 143.5 FPS, which is likely near the CPU's practical limit for this game, but at 1080p High the frame rate drops to 86.2 FPS, a 40% reduction that is clearly GPU-driven. The CPU's six threads are adequate for Rust, as the game rarely uses more than four or five cores effectively. The i5-9400's single-core performance is also sufficient, given that its nearest rival, the i3-10305, scores nearly identically (0.2% faster) and would not produce a meaningful difference in frame rates.

Where the CPU does matter is in maintaining minimum frame rates during complex scenes. The 1080p Low result of 143.5 FPS shows the CPU can feed the GPU enough frames, but the lack of hyper-threading means there is no headroom for background tasks or heavy server-side calculations. The benchmark data shows the i5-9400 is a balanced partner for the GTX 1080 Ti in Rust, neither holding the system back at lower settings nor being the reason for the poor 4K Ultra result. That failure belongs entirely to the GPU's limited pixel throughput at high resolutions.