Microsoft Flight Simulator

Microsoft Flight Simulator presents one of the most demanding real-time rendering workloads in the database, and the pairing of the Intel Core i5-9400 with the NVIDIA GeForce RTX 5090 D produces a distinctive performance profile. The measured data reveals a system where the GPU’s immense computational headroom is often constrained by the CPU’s six-core architecture, leading to scaling behavior that is more nuanced than the raw hardware specifications might suggest. This analysis walks through the resolution scaling, component roles, and ranking data to provide a methodical breakdown of what this combination delivers in the 2020 flight simulator.

Resolution Scaling — how FPS drops from 1080p to 4K and what it says about the limiting component

The measured FPS across resolutions shows a pattern of diminishing returns that points directly at the CPU as the primary bottleneck, particularly at lower resolutions. At 1080p with Low settings, the combination achieves 128 FPS average. Moving to 1440p Low drops that to 119 FPS, a reduction of 9 FPS, and then to 4K Low it falls further to 108 FPS, another 11 FPS loss. The total scaling from 1080p to 4K at Low settings is a 20 FPS drop, which translates to approximately a 15.6% reduction in frame rate.

This relatively modest drop across a 4x increase in pixel count (from 1920x1080 to 3840x2160) is a clear indicator that the system is not GPU-limited at the Low preset. If the RTX 5090 D were the limiting factor, the frame rate would typically fall by a much larger percentage when pixel count quadruples. Instead, the data suggests that at 1080p and 1440p Low, the Intel Core i5-9400 is holding back the GPU, preventing it from fully utilizing its rendering capabilities. The i5-9400’s six cores and six threads, with a boost clock of 4.10 GHz, can only feed the RTX 5090 D so many draw calls and simulation updates per second.

The pattern shifts slightly when looking at higher settings. From 1080p High (105 FPS) to 1440p High (98 FPS), there is a 7 FPS drop, and then to 4K High (88 FPS), another 10 FPS drop. The total scaling from 1080p to 4K at High is 17 FPS, or about 16.2%. At Ultra settings, the progression is from 104 FPS at 1080p, to 96 FPS at 1440p, and finally to 84 FPS at 4K. That is a 20 FPS total drop, or a 19.2% reduction. The slightly steeper percentage drop at Ultra settings indicates that the GPU is starting to become more of a participant in the bottleneck, as the increased shading and texture work begins to tax the RTX 5090 D more heavily, though it still never becomes the sole limiting factor.

The Medium preset offers the only complete data with min and max FPS at each resolution. At 1080p Medium, the average is 117 FPS with a minimum of 99 and a maximum of 134. At 1440p Medium, the average is 109 FPS with a minimum of 92 and a maximum of 125. At 4K Medium, the average is 98 FPS with a minimum of 83 and a maximum of 113. The minimum FPS values also scale down proportionally, confirming that even the worst-case frame times are affected by the same resolution-dependent factors. The consistent delta between resolutions suggests that the CPU overhead for simulation logic remains constant, while the GPU rendering time increases with resolution, but not enough to dominate.

GPU Role — VRAM, clocks, and how they relate to this game's results

The NVIDIA GeForce RTX 5090 D is a flagship GPU with specifications that are almost absurdly over-provisioned for Microsoft Flight Simulator at these measured settings. It features 32 GB of GDDR7 memory on a 512-bit bus, yielding a bandwidth of 1.79 TB/s. The card’s base clock is 2017 MHz with a boost clock of 2407 MHz, and it has 21760 shading units. These specifications place it in the 92nd percentile of all GPUs in the database, with an average benchmark score of 77712.

The nearest rivals to the RTX 5090 D, based on average benchmark scores, are the AMD Radeon RX 6650M XT, the AMD Radeon RX 6850M XT, and two NVIDIA Tesla P100 variants. The RX 6650M XT scores 76904, which is 1.1% lower than the RTX 5090 D’s average. The RX 6850M XT scores 78940, which is 1.6% higher. The Tesla P100 PCIe 12 GB and 16 GB versions score 79396 and 79605, respectively, which are 2.1% and 2.4% higher. This tight clustering of scores around the RTX 5090 D’s average is notable, as it suggests that the raw compute benchmarks do not fully separate the 5090 D from these other cards, despite the massive differences in memory size and bandwidth.

In the context of Microsoft Flight Simulator, the GPU’s role is primarily to render terrain, aircraft models, and weather effects. The 32 GB VRAM is far more than the game needs at these settings, ensuring that there is no texture swapping or memory pressure. The 1.79 TB/s memory bandwidth allows for high-resolution texture streaming without stutter. However, the measured FPS data shows that the GPU is not the limiting factor. At 4K Ultra, the combination only achieves 84 FPS, which is far below what the RTX 5090 D is capable of in less CPU-bound scenarios. The GPU’s high pixel rate of 423.6 GPixel/s and texture rate of 1,636.8 GTexel/s are simply waiting on the CPU to provide more work.

The GPU’s benchmark percentile of 92 indicates that it outperforms the vast majority of GPUs in the database, but the measured FPS in this game are not in the top percentile of results. This discrepancy highlights the importance of the CPU pairing. The RTX 5090 D is effectively throttled by the i5-9400 in this specific workload. The game’s simulation logic, which includes flight physics and world data streaming, is heavily single-threaded or lightly threaded, and the i5-9400’s 6-core, 6-thread configuration with a 4.10 GHz boost clock is not enough to keep the GPU saturated.

How This Combo Ranks — use comboRankInGame vs other tested combos

The combination of the Intel Core i5-9400 and the NVIDIA GeForce RTX 5090 D is ranked 480th out of 2996 tested combos in Microsoft Flight Simulator. This places it in the top 16% of all combinations in the database for this specific game. While this is a strong overall ranking, it is important to contextualize it against the capabilities of the individual components. The GPU alone is in the 92nd percentile of all GPUs, and the CPU is in the 47th percentile of all CPUs.

The rank of 480 out of 2996 suggests that there are many other combinations that achieve higher FPS in this game. The gap between the GPU’s high percentile and the combo’s lower rank is a direct consequence of the CPU bottleneck. The i5-9400’s average benchmark score is 2254, which places it in the 47th percentile of all CPUs. Its nearest rivals, based on average score, are the Intel Core i7-1068NG7 (2259, -0.2% delta), the Intel Core i7-10710U (2248, +0.3% delta), the AMD Ryzen 5 PRO 1500 (2246, +0.4% delta), and the Intel Core i3-10305 (2264, -0.4% delta). These rivals are all in the same performance tier, indicating that the i5-9400 is a mid-range CPU from a bygone era.

The combo’s rank of 480 is likely driven by other systems that pair the RTX 5090 D (or similar high-end GPUs) with stronger CPUs. A CPU with more cores and higher single-thread performance would allow the RTX 5090 D to reach higher FPS in this game, particularly at lower resolutions. The data shows that the combo is capable of producing playable frame rates at all settings, but it is not extracting the full potential from the GPU. For a user who already owns the i5-9400 and is looking at a GPU upgrade, this ranking suggests that the RTX 5090 D is a viable, albeit mismatched, partner. The GPU will deliver massive improvements over any previous card, but the CPU will cap the frame rates.

Measured FPS Breakdown — resolution by resolution, settings by settings, exact numbers

The measured FPS data provides a complete picture of the combo’s performance across three resolutions and four settings presets. The following breakdown details each data point.

At 1920x1080, the lowest resolution tested, the combo delivers its highest frame rates. With Low settings, the average FPS is 128. Moving up to Medium settings, the average drops to 117 FPS, with a minimum of 99 and a maximum of 134. The High preset yields an average of 105 FPS. The Ultra preset offers an average of 104 FPS. The difference between High and Ultra at 1080p is only 1 FPS, suggesting that the Ultra preset’s additional effects are not heavily taxing the GPU at this resolution, and the CPU is still the primary limiter.

At 2560x1440, the frame rates begin to show a more pronounced separation between settings. Low settings produce an average of 119 FPS. Medium settings drop to 109 FPS, with a minimum of 92 and a maximum of 125. High settings average 98 FPS. Ultra settings average 96 FPS. The gap between High and Ultra remains narrow at 2 FPS, but the gap between Low and Ultra has grown to 23 FPS. This is a larger spread than at 1080p, indicating that the GPU is starting to have a more significant impact on performance as the pixel count increases.

At 3840x2160, the highest resolution tested, the combo’s performance converges. Low settings produce an average of 108 FPS. Medium settings average 98 FPS, with a minimum of 83 and a maximum of 113. High settings average 88 FPS. Ultra settings average 84 FPS. The spread between Low and Ultra is now 24 FPS. The minimum FPS at 4K Medium is 83, which is still well above the threshold for smooth gameplay in a flight simulator, but it shows that the system can have occasional dips. The maximum FPS at 4K Medium is 113, which is higher than the average FPS at 4K High (88), showing that the preset settings have a significant impact on the frame rate ceiling.

CPU Role — cores, clocks, and how they relate to this game's results

The Intel Core i5-9400 is a Coffee Lake Refresh architecture processor, manufactured on a 14 nm process node. It has 6 cores and 6 threads, with a base clock of 2.90 GHz and a boost clock of 4.10 GHz. The CPU supports DDR4 memory in a dual-channel configuration, with a memory bandwidth of 42.7 GB/s. Its L3 cache is 9 MB shared. The CPU’s benchmark scores are modest: it scores 6629 in Cinebench R23 multi-core and 935 in single-core, and 5141 in Geekbench multi-core and 1389 in single-core. Its average benchmark score is 2254, placing it in the 47th percentile of all CPUs.

In Microsoft Flight Simulator, the CPU is responsible for the complex simulation of flight dynamics, weather systems, and the streaming of world data. This workload is known to be sensitive to single-thread performance, as many of the core simulation tasks are not perfectly parallelized. The i5-9400’s 4.10 GHz boost clock is decent, but its 6-core/6-thread configuration lacks the multi-threading (Hyper-Threading) that would allow it to handle more concurrent simulation tasks. The lack of extra threads means that when the game tries to distribute work across more than six threads, the CPU cannot provide it, leading to potential stalls.

The CPU’s percentile of 47 indicates that it is an average performer in the database. Its nearest rivals include the Intel Core i7-1068NG7 and the AMD Ryzen 5 PRO 1500, all of which have similar average benchmark scores. This confirms that the i5-9400 is not a high-end part, and its age (released in 2018) means it lacks the architectural improvements of newer CPUs. The measured FPS data in this game suggest that the CPU is the bottleneck at 1080p and 1440p, as the frame rates do not scale down as much as they would if the GPU were the limiter.

The CPU’s memory bandwidth of 42.7 GB/s is also a potential limitation, as the game benefits from fast memory access. However, the impact of memory bandwidth is difficult to isolate from the core clock and thread count. The data shows that the combo achieves 128 FPS at 1080p Low, which is a high frame rate, but it is likely that a newer CPU with higher single-thread performance would push this number higher. The CPU’s role is to feed the GPU, and in this case, it is not feeding it enough.

FAQ

Q: What is the highest average FPS this combo achieves in Microsoft Flight Simulator?

A: The highest average FPS is 128, achieved at 1920x1080 resolution with Low settings.

Q: How much does the frame rate drop when moving from 1080p to 4K at Ultra settings?

A: At Ultra settings, the average FPS drops from 104 at 1080p to 84 at 4K, a decrease of 20 FPS.

Q: Is the GPU or CPU the primary bottleneck in this configuration?

A: The data indicates the CPU is the primary bottleneck, as frame rates do not scale down as steeply as expected with increasing resolution, particularly at Low and Medium settings.

Q: What is the combo’s rank among all tested combinations in this game?

A: The combo is ranked 480th out of 2996 tested combos in Microsoft Flight Simulator.

Q: What is the minimum FPS recorded at 4K Medium settings?

A: The minimum FPS recorded at 4K Medium settings is 83.

Q: How does the CPU’s average benchmark score compare to its nearest rival, the Intel Core i7-1068NG7?

A: The Intel Core i5-9400 has an average benchmark score of 2254, which is 0.2% lower than the Intel Core i7-1068NG7’s score of 2259.

Settings Recommendations

Based on the measured FPS data, the optimal settings for this combo depend on the user’s priority for frame rate versus visual fidelity. The data shows that the CPU bottleneck is most pronounced at lower resolutions and settings, where the GPU is not fully utilized. Therefore, the choice of settings should be guided by the desired resolution.

For users playing at 1920x1080, the Ultra preset provides an average of 104 FPS, which is only 1 FPS lower than the High preset’s 105 FPS. Given the negligible performance cost, the Ultra preset is the recommended choice for 1080p, as it delivers the best visual quality without a meaningful frame rate penalty. The Low preset’s 128 FPS is only relevant for users with high-refresh-rate monitors who prioritize frame rate above all else, but the visual downgrade is substantial.

At 2560x1440, the Ultra preset’s 96 FPS is only 2 FPS lower than the High preset’s 98 FPS. The Medium preset offers 109 FPS. For a balanced experience, the High preset is a reasonable choice, as it provides a solid frame rate (98 FPS) and good visual quality. However, the Ultra preset’s 96 FPS is still well above the threshold for smooth gameplay in a flight simulator, and the visual enhancements are likely worth the 2 FPS cost. The Medium preset’s higher frame rate (109 FPS) could be preferred by users who want a larger margin over the minimum FPS threshold, but the quality drop from High to Medium is noticeable.

At 3840x2160, the Ultra preset provides 84 FPS, while the High preset provides 88 FPS. The Medium preset provides 98 FPS. The difference between High and Ultra is 4 FPS, which is small. The difference between High and Medium is 10 FPS, which is more significant. The data shows that the system is still CPU-bound at 4K, as the frame rates are relatively high for the resolution. The Medium preset’s 98 FPS average with a minimum of 83 FPS offers the best combination of high frame rate and stability. The High preset’s 88 FPS average is also acceptable, but the Medium preset provides a more comfortable margin. Given that the GPU has plenty of VRAM and bandwidth, the Medium preset’s lower visual settings are less impactful than the frame rate gain it provides. The Ultra preset, while visually stunning, pushes the average down to 84 FPS, which is still playable but offers less headroom for complex scenery. For a consistently smooth experience at 4K, the Medium preset is the recommended choice.