Stress My GPU

How the SMG Verdict Works

A single FPS number hides most of what matters. Two GPUs can both average 60 FPS while one is perfectly smooth and the other stutters or slows down after two minutes. The SMG Verdict is how Stress My GPU turns one test run into an honest, readable judgement of what your GPU did under load.

The five-axis load profile

Every completed run is scored on five axes from 0 to 100.

  1. Power. How much work the GPU got through. It is derived from the Stress My GPU Score, which already accounts for the test, intensity, resolution and duration.
  2. Steadiness. How consistent frame times were: 60% frame-time stability (one minus the coefficient of variation) and 40% the ratio of your 1% low to your average FPS.
  3. Endurance. Whether performance held over time. The run is split into eight time slices; the average FPS of the last two slices is compared with slices two and three (the first slice is skipped because shader compilation and clock ramp-up distort it). A drop of 30% or more scores zero; no drop scores 100. This is what exposes thermal and power throttling.
  4. Pacing. The share of frames delivered within 25% of the median frame time. High pacing means evenly spaced frames, which looks smooth even at moderate FPS.
  5. Spike control. How well the worst moments were contained, based on the 0.1% low relative to the average and the number of hitches (frames slower than 2.5 times the median) per minute.

Named scores, class score and SMG Rating

Every test reports its own named score: Render, Particle, Shader, Memory, Volume, Decode, Compute, Integrity Load and Limit. The raw score depends on the intensity and resolution you chose, so we also show a class score that divides those factors out. A GPU holding a steady 60 FPS has a class score of about 2,000, and 144 FPS is about 4,800. Class scores map to five performance classes: Entry (under 700), Mainstream (700+), Performance (2,000+), High-end (4,500+) and Enthusiast (9,000+). Your SMG Rating in My Results is the average of your best class score in each test you have run, so a fuller set of tests gives a fuller profile.

SMG Index and tier

The axes combine into a single SMG Index out of 100: Power 35%, Steadiness 20%, Endurance 15%, Pacing 15%, Spike control 15%. The index maps to a tier: S (85+), A (72+), B (58+), C (42+) and D (below 42). The tier describes this run at this load, not the GPU in general: the same GPU earns a lower tier at Low intensity than at High, because it was given less to do. Run at an intensity that does not simply hit your display’s refresh-rate cap.

GPU personas

The shape of the profile selects a persona that summarises behaviour in one phrase.

  • Workhorse – high Power, and it held that level to the end.
  • Marathoner – exceptionally consistent over time at a moderate load.
  • Metronome – extremely even frame delivery.
  • Sprinter – strong output that fades or wobbles.
  • Heat-Soaker – clear slowdown during the run, typical of throttling.
  • Hitch-Prone – good average, but frequent spikes.
  • All-Rounder – no standout strength or weakness.

Readiness estimates

The verdict also estimates suitability for common uses: web and video, casual 3D, 1080p gaming, high-refresh gaming, 1440p and 4K. These are heuristics derived from your run normalised to a reference load. They are guides, not guarantees, and they say “at least” when your result looks capped by display refresh.

Stress My GPU Score

Score = 1000 × (sustained FPS / 60) × consistency × workload weight × intensity multiplier × resolution² × duration factor. Sustained FPS blends 50% average, 30% 1% low and 20% 0.1% low. Intensity multipliers are 1, 2, 4 and 8 for Low to Extreme, and 64 for Torture (Extreme with eight stacked passes of the same work, so every frame costs roughly eight times as much). The Limit Score uses the same formula with a load factor: the finder raises the load step by step (x1, x2, x3, x4, x6, x8, x12 and on up to x64) for five seconds each until it can no longer hold 60% of your display refresh rate (never below 30 FPS), then holds the last sustainable step and scores that hold. Because the load factor rises as your GPU copes with more, the Limit Score is not capped by your monitor’s refresh rate. It also reports the GPU time per frame, from a hardware timer when your browser exposes one and otherwise from wall-clock time while below vsync. This score is unique to this site and is not comparable to 3DMark, FurMark, SPEC or any other benchmark.

Rigorous tests and error detection

The Integrity test runs a deterministic shader whose exact output is known, reads back sample tiles and compares them with the first pass and with a reference calculated on your CPU. It also writes bit patterns into video memory, leaves them for a moment and checks they read back unchanged. Any mismatch is counted as an error with a timestamp. Zero errors is reported as PASS for this run only; one or more errors is reported as FAIL, rated tier D and shown as Unstable. The check can only detect wrong results the browser lets it read back. It cannot see temperature, clocks or power, and WebGL cannot exercise tensor or ray-tracing hardware, so a PASS is not a guarantee of long-term stability.

The Rigorous stress suite chains six phases (shader load, memory bandwidth, geometry, integrity, limit finder and a repeat of the first phase). It ends as FAIL on any error, driver reset or context loss, or a drop of more than 15% from the first to the last phase, as WARNING for a smaller drop or a run that was reduced or stopped early, and as PASS otherwise. Torture and the suite stop themselves if two frames in a row take more than two seconds.

Limits and honesty

  • Browsers cap rendering to your display’s refresh rate, so light workloads may read as capped.
  • Web pages cannot read GPU temperature, clocks or power. Endurance infers throttling from performance, not from sensors.
  • The GPU name is whatever the browser reports and may be masked.
  • Runs shorter than 60 seconds produce low-confidence Endurance readings; the verdict says so.
  • Everything is computed on your device. Results are only sent to the server if you tick the consent box, and the verdict itself is never sent.