NVIDIA Reflex on RTX 5090: Turning 4K FPS Into Real Low-Latency Gameplay

NVIDIA Reflex is a low-latency technology built into supported games and G-Sync displays that shortens the time between your input and what you see on screen. It works by tightening the render pipeline between CPU, GPU and monitor so frames are generated “just in time”, cutting the render queue and reducing system latency – especially when you’re using DLSS, V-Sync or Frame Generation on an RTX 5090.

This guide shows you how to use Reflex properly on an RTX 5090 / RTX 50-series build at 4K: what it actually does, how Reflex 2 + Frame Warp fits in, and how to combine it with G-Sync, VRR, DLSS 4 and Multi Frame Generation without making the game feel “laggy”.

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1. Why Latency Matters More Than Just “High FPS”

You already know high average FPS ≠ genuinely smooth gameplay. A similar truth applies here:

• You can have 140+ FPS at 4K on an RTX 5090
• But if each frame has been sat in a queue for a few milliseconds too long
• The game still feels sluggish, as if your crosshair is dragging through mud

That’s because what your eyes see can easily be one or two frames behind your latest mouse movement. Reflex attacks that problem directly by changing how work is scheduled between CPU and GPU.

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2. Where System Latency Actually Comes From

Every frame goes through a pipeline:

1. You click / move the mouse.
2. The CPU updates game logic (position, physics, hit detection, AI).
3. The CPU sends draw calls to the GPU.
4. The GPU renders the frame.
5. The display scans the frame out to your eyes.

Most engines queue up some work ahead of the GPU to keep it busy. If that queue gets too deep, your inputs are effectively buffered – by the time the frame reaches the screen, it’s already “old”.

Traditional tweaks like “Maximum pre-rendered frames” or Ultra Low Latency Mode in the driver try to limit that queue from outside the game. Reflex goes further by giving the engine itself control over timing.

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3. What NVIDIA Reflex Actually Is

Reflex has two main parts:

3.1 Reflex Low Latency Mode (in games)

This is the bit you see in settings menus:

• NVIDIA Reflex Low Latency: Off / On / On + Boost

It’s an SDK integrated by the game developer. The engine uses it to:

• Coordinate CPU and GPU work
• Shrink or remove the render queue
• Schedule frames “just in time” so they are as fresh as possible when they hit the display

3.2 Reflex Latency Analyzer (in some G-Sync monitors)

Certain G-Sync esports monitors have Reflex Latency Analyzer built in:

• You plug a compatible mouse into the monitor
• The game shows a small Reflex “flash” when you fire
• The monitor measures click-to-photon time (mouse click → on-screen flash) and reports system latency in milliseconds

You don’t need Analyzer to benefit from Reflex, but it’s invaluable if you want to prove your settings really are cutting latency rather than just “feeling” better.

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4. Reflex 2 and Frame Warp on RTX 50-Series

With Blackwell / RTX 50-series, NVIDIA introduced Reflex 2 with Frame Warp:

• The engine renders a frame as normal
• Just before scan-out, Reflex 2 warps that frame based on your latest mouse input
• The idea is to adjust the final image at the last moment so it better reflects your most recent movement

In NVIDIA’s own demos and early press coverage:

• Baseline latency might be ~27 ms
• Reflex 1 (original) can pull it to the mid-teens
• Reflex 2 + Frame Warp has shown numbers around 8–10 ms in supported titles, a very substantial reduction

This is especially important because RTX 50-series leans heavily on DLSS 4 and Multi Frame Generation (MFG) for huge FPS boosts – and Frame Generation, by its nature, tends to increase latency. Reflex 2 exists to claw that latency back.

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5. Reflex, DLSS 4 and Multi Frame Generation on RTX 5090

On an RTX 5090 at 4K you’ll frequently see this trio:

• DLSS Super Resolution (Quality/Balanced/Performance)
• Frame Generation (DLSS 4 / Multi Frame Generation)
• NVIDIA Reflex Low Latency

Super Resolution is mostly about performance vs image quality. Frame Generation, however, interpolates extra frames between real ones – which almost always increases input lag if used alone.

The recommended stack for modern titles looks like:

1. Enable DLSS Quality (or Balanced) at 4K to stabilise base FPS.
2. Turn on Reflex: On (or On + Boost) to minimise latency.
3. If base FPS is healthy (e.g. 60+), enable Frame Generation / Multi Frame Generation to push perceived smoothness even higher.
4. Keep VRR (G-Sync / FreeSync) on and use a sensible FPS cap so frametimes stay clean.

On RTX 50-series, Reflex + Frame Warp is explicitly designed to make these AI features feel responsive instead of detached.

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6. Reflex Settings: Off vs On vs On + Boost

In supported games you’ll usually find:

• Off
• On
• On + Boost

Off

• Engine uses its default scheduling
• Input lag is whatever the game would normally have
• You’re leaving performance on the table on an RTX 5090 if you care about responsiveness

On

• Engine uses the Reflex SDK to minimise queueing
• NVIDIA and independent tests show significant latency reductions – often 20–50% or more depending on the title and baseline.
• FPS impact is usually very small, often within margin of error.

On + Boost

• Same latency optimisations as On
• Also raises GPU clocks / prevents them idling down between frames
• Best when:
  • You’re playing competitive modes
  • You’re slightly CPU-limited and the GPU isn’t being pushed hard
  • You want every bit of responsiveness you can get

On an RTX 5090 at 4K:

• Single-player / cinematic: use On.
• High-refresh AAA (120–144 Hz): start with On, then try On + Boost if clocks are wobbling.
• Competitive shooters: go straight to On + Boost and combine with a good FPS cap.

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7. Reflex vs NVIDIA Low Latency Mode in the Driver

You’ve also got Low Latency Mode in the NVIDIA Control Panel (Off / On / Ultra). It’s important to understand how this interacts with Reflex.

NVIDIA’s own latency guide is very clear:

• If a game uses the Reflex SDK, that takes priority
• Ultra Low Latency (NULL) in the driver is mainly for games that don’t support Reflex at all
• When both are enabled, Reflex overrides the driver’s Ultra Low Latency behaviour

So on RTX 50-series:

• Use a global profile with Low Latency Mode = On as a safe baseline.
• In Reflex-enabled games, just turn Reflex On / On + Boost and treat driver low latency as secondary.
• In older games without Reflex, you can create per-game profiles with Low Latency Mode = Ultra, especially if you’re GPU-bound and using V-Sync.

That keeps the hierarchy simple: Reflex first, driver NULL only when there is no Reflex option.

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8. Step-by-Step: Setting Up Reflex on a 4K RTX 5090 Rig

Step 1 – Make sure sync and display basics are correct

• Ensure your 4K monitor/TV is running 3840×2160 at 120 or 144 Hz.
• Enable G-Sync / G-Sync Compatible / FreeSync in NVIDIA Control Panel and on the display.
• Pick a sync strategy:
  • Common pattern: V-Sync On in the driver, Off in-game, with an FPS cap a few frames below refresh to sit nicely in the VRR range.

Step 2 – Turn on Reflex in each supported game

In each title:

• Go to Graphics / Video / Gameplay
• Set NVIDIA Reflex Low Latency → On
• For competitive modes or high-refresh play, use On + Boost

Step 3 – Add DLSS and Frame Generation as needed

• Start with DLSS Quality at 4K to take the edge off GPU load.
• If base FPS is healthy and you want extra smoothness, enable Frame Generation / Multi Frame Generation.
• Keep Reflex enabled to offset the extra input lag FG introduces.

Step 4 – Cap FPS sensibly

• On a 120 Hz display: cap around 117–118 FPS.
• On 144 Hz: cap around 140–141 FPS.
• Use the in-game limiter or NVIDIA Max Frame Rate in a per-game profile, not both at once.

This stops you slamming into the top of the VRR window, which can cause micro-stutter and inconsistent frametimes.

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9. Measuring the Difference: Latency Overlays and Reflex Analyzer

If you want to prove Reflex is doing something:

In-game latency overlays

Many Reflex-enabled games expose a latency overlay or graph:

• It shows system latency in milliseconds
• You can compare:
  • Reflex Off vs On
  • On vs On + Boost
  • With and without Frame Generation

This is the easiest way to see concrete numbers without extra kit.

Reflex Latency Analyzer

If you have a G-Sync display with Reflex Analyzer, you can:

• Plug your mouse into the monitor’s Analyzer port
• Enable the flash indicator in supported games
• Read latency directly from the monitor’s overlay

It’s particularly handy when tuning your RTX 5090 for ranked matches – you can see exactly how much latency each setting costs or saves.

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10. Practical Presets You Can Recommend on Your Site

These are great to reuse as “copy-paste” configs in other RTX 5090 articles.

A. Cinematic 4K Single-Player (60–90 FPS target)

• Resolution: 3840×2160
• DLSS: Quality
• Frame Generation: Optional – only if base FPS is solid
• Reflex: On
• VRR: On (G-Sync / FreeSync)
• V-Sync: On in driver, Off in-game
• FPS cap: 70–85 FPS

Feels like a high-end showcase, still responsive enough that controller or mouse doesn’t feel laggy.

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B. High-Refresh 4K AAA (100–144 FPS target)

• Resolution: 3840×2160
• DLSS: Quality/Balanced
• Frame Generation: On in DLSS 4 games if base FPS is 60–80+
• Reflex: On, test On + Boost if GPU clocks aren’t staying high
• VRR: On
• FPS cap: 117–118 (120 Hz) or 140–141 (144 Hz)

Great for third-person action, racing and modern shooters where you want a mix of fidelity and pace.

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C. Competitive Shooter / Ranked Play

• Resolution: 4K (or 1440p if you prefer)
• DLSS: Quality or Off if aliasing is acceptable
• Frame Generation: Off – lowest latency matters more than extra FPS
• Reflex: On + Boost
• V-Sync: Off (VRR only)
• FPS cap: just below refresh with in-game limiter
• Extra effects: Motion blur, film grain, heavy DOF → Off

This is your “sweaty ranked” preset: uncompromising on responsiveness.