Compatibility

Four documents#

Compatibility is precomputed for every pair, in both directions, and published as four kinds of document:

Every board and chassis has a fits document, every board a can-run document and every model a runs-on document, discontinued records included. Each detail document links its own in data.compatibility: fits and canRun on a board, fits on a chassis, runsOn on a model.

On each of them, links.self is the compatibility URL, while links.page and links.text point at the subject's web page and .txt, where the same answers are shown. asOf is the latest time any value in the document was retrieved or verified: the subject's own values, those of every entity in the items, and those of every entity named in an item's benchmark results. It is null when none of them has a recorded time.

Fit#

curl -s https://gpuninja.com/api/v1/boards/asus-rog-strix-4090/fits

{
  "apiVersion": "v1",
  "kind": "board-fits",
  "asOf": "2026-10-04T06:12:00Z",
  "board": {
    "slug": "asus-rog-strix-4090",
    "name": "ASUS ROG Strix GeForce RTX 4090 OC",
    "lengthMm": 357.6,
    "slotWidth": 3.5
  },
  "rule": { "checkMarginMm": 10 },
  "counts": { "fits": 0, "check": 0, "doesNotFit": 1 },
  "items": [
    {
      "chassis": {
        "slug": "fractal-north",
        "name": "Fractal Design North",
        "maxGpuLengthMm": 355,
        "maxGpuSlots": 3
      },
      "fit": {
        "verdict": "does-not-fit",
        "basis": "dimensions",
        "reasons": [
          { "code": "length-exceeds", "boardLengthMm": 357.6, "clearanceMm": 355, "marginMm": -2.6 },
          { "code": "slots-exceed", "boardSlotWidth": 3.5, "maxSlots": 3 }
        ]
      },
      "psu": { "includedW": null, "recommendedW": 1000, "sufficient": null }
    }
  ],
  "links": {
    "self": "https://gpuninja.com/api/v1/boards/asus-rog-strix-4090/fits",
    "page": "https://gpuninja.com/boards/asus-rog-strix-4090",
    "text": "https://gpuninja.com/boards/asus-rog-strix-4090.txt"
  }
}

(Abridged: the board and chassis objects are full summaries in the real response.)

Verdicts#

fit.verdict is one of three values:

The rule#

When no override exists, basis is "dimensions" and the verdict comes from two comparisons:

1. Length. The margin is the case's maxGpuLengthMm minus the card's lengthMm, compared exactly in tenths of a millimetre.
   • Either value unknown: length-unknown, which counts as check.
   • Margin below 0: length-exceeds, does-not-fit.
   • Margin from 0 to 10.0 mm inclusive: length-tight, check. This is the 10 mm rule, published as rule.checkMarginMm.
   • Margin above 10.0 mm: length-clear, fits.
2. Slots. The card's slotWidth against the case's maxGpuSlots, compared exactly in hundredths of a slot, so a 3.04-slot card does not fit a 3-slot case and a 3.00-slot card does.
   • Either value unknown: slots-unknown, check.
   • Card wider than the slot count: slots-exceed, does-not-fit.
   • Otherwise: slots-ok, fits.

The verdict is the worse of the two, where does-not-fit is worse than check, which is worse than fits. reasons holds both, length first. Length reasons carry boardLengthMm, clearanceMm and marginMm (negative when the card is too long); slot reasons carry boardSlotWidth and maxSlots. The -unknown reasons carry only their code.

At the boundaries: a margin of exactly 10.0 mm is check and 10.1 mm is fits; a margin of exactly 0.0 mm is check and −0.1 mm is does-not-fit. marginMm is always a whole number of tenths, written with at most one decimal place (7.4, never 7.400000000000034).

Overrides#

Dimensions occasionally give the wrong answer, for instance when a card fits only with the front fans removed. A maintainer can then record an override, which always carries a note. With an override, basis is "override", the verdict is fits or does-not-fit as recorded, and reasons holds a single reason:

{
  "verdict": "fits",
  "basis": "override",
  "reasons": [
    { "code": "override", "fits": true, "note": "Verified with front fans removed; see manufacturer FAQ." }
  ]
}

PSU advisory#

Each item has a psu object: the case's includedW (the wattage of a bundled power supply, if any), the card's recommendedW, and sufficient, which is includedW >= recommendedW when both are known and null otherwise. The advisory never changes the fit verdict.

Counts and ordering#

counts gives the number of items with each verdict (fits, check, doesNotFit). Items are ordered fits first, then check, then does-not-fit, and by the other entity's slug within each verdict.

A board's fit against a case is always identical in the board's document and in the case's document.

Can-run and runs-on#

curl -s https://gpuninja.com/api/v1/boards/asus-rog-strix-4090/can-run
curl -s https://gpuninja.com/api/v1/models/llama-3-1-8b-q4/runs-on

{
  "apiVersion": "v1",
  "kind": "board-can-run",
  "asOf": "2026-10-04T06:12:00Z",
  "board": { "slug": "asus-rog-strix-4090", "vramGb": 24 },
  "determinable": true,
  "items": [
    {
      "model": { "slug": "llama-3-1-8b-q4", "name": "Llama 3.1 8B Q4_K_M", "minVramGb": 6 },
      "headroomGb": 18,
      "results": []
    }
  ],
  "links": {
    "self": "https://gpuninja.com/api/v1/boards/asus-rog-strix-4090/can-run",
    "page": "https://gpuninja.com/boards/asus-rog-strix-4090",
    "text": "https://gpuninja.com/boards/asus-rog-strix-4090.txt"
  }
}

(Abridged: the board and model objects are full summaries in the real response.)

The rule compares the card's vramGb with the model's minVramGb, to a hundredth of a gigabyte:

• A card can run a model when its VRAM is at least the model's minimum. Equality counts: a 24 GB card runs a model that needs 24 GB, with headroomGb: 0, but not one that needs 24.01 GB. headroomGb is the difference, a whole number of hundredths, so it is never negative.
• Only pairs that can run appear as items. A card with too little VRAM is simply absent.
• If either value is unknown, the pair can't be decided and is left out. When the subject's own value is unknown, determinable is false and items is empty; otherwise it is true.
• results lists the benchmark results for that model whose subject is that card or the card's chip (subject.kind tells you which).

can-run items are ordered by the model's minVramGb, largest first, then model slug. runs-on items are ordered by headroomGb, smallest first, then board slug, so the tightest fits come first.

Can-run is a VRAM check only. It says the model's weights fit; how fast it runs is what the benchmark results are for.

Discontinued hardware#

Fit and can-run are recomputed on every build for discontinued boards and chassis too, so a discontinued card is checked against cases and models added after it was frozen, by the same rules. Its summary in these documents shows status: "discontinued", inStock: false and lowestPriceUsd: null.