pplx-decider v1.1 27B VRAM requirements
Perplexity’s pplx-decider-v1.1-27b assigns probabilities to named choices using a Qwen3.8-27B backbone and a separate decision head. It accepts text and images. Use its decision implementation to preserve the saved attention mode and calibration.
48.59 GiB published BF16 weights only
- Backbone parameters (HF)
- 26,085,330,160
- Checkpoint
- 11 backbone shards + decision head
- Input limit in the supplied loader
- 8,192 tokens including images
- Measured peak VRAM
- Not measured by ModelVRAM
Which GPU holds the published checkpoint?
| GPU capacity | BF16 weights fit? | What this tells you |
|---|---|---|
| 24 GiB / RTX 4090 | No | The weights exceed capacity before any forward pass. |
| 32 GiB / RTX 5090 | No | The original checkpoint cannot reside fully on the card. |
| 48 GiB / L40S | No | 48.59 GiB of files leaves no space even for the weights. |
| 80 GiB / A100 or H100 | Yes, weights only | Working memory and workload limits need a real run. |
GiB means 1,073,741,824 bytes. File bytes include safetensors headers. The separate head is 2.49 MiB; it is included in the total, not an extra download after the estimate.
Why a chat-model VRAM estimate is insufficient
The checkpoint replaces the language-model output head with a 255 × 5,120 BF16 readout. Its full-attention layers read the input noncausally; the linear-attention layers retain their own behavior. There is no chat decoding loop to size with the site’s usual growing generation cache or tokens-per-second estimate.
Longer input, more images and a larger batch still increase activations and attention working memory. The supplied loader limits the complete request to 8,192 positions. For the publisher’s evaluation setting, cap each image at 512 × 512 pixels; its default higher cap permits up to 4,096 visual tokens per image and costs more memory.
INT4 and FP8 weight arithmetic alone cannot establish a working Decider deployment. A quantized export must preserve the readout, saved attention behavior and calibrated probabilities. We have not tested one.
Load the official decision implementation
Use Python 3.12 or newer and a CUDA environment with enough free memory. Download the repository, then install its pinned requirements.txt. The model card mentions authenticated access; check the repository’s current access requirements when downloading.
hf download perplexity-ai/pplx-decider-v1.1-27b --local-dir pplx-decider-v1.1-27b pip install -r pplx-decider-v1.1-27b/requirements.txt import sys
from pathlib import Path
from huggingface_hub import snapshot_download
checkpoint = Path(snapshot_download("perplexity-ai/pplx-decider-v1.1-27b"))
sys.path.insert(0, str(checkpoint / "source" / "src"))
from autojev.model import DecisionModel, answer
model = DecisionModel(checkpoint, device="cuda", max_image_pixels=512 * 512)
question = {
"type": "choice",
"instructions": "Route this request to a team.",
"criteria": {"billing": "Payments and refunds", "support": "Integration faults"},
}
probabilities = model.predict([{"state": "My API request fails.", "question": question}])[0]
print(answer(question, probabilities)) Example follows the publisher’s DecisionModel API. It has not been executed on a GPU by ModelVRAM. Use predict’s calibrated distribution; do not apply the saved temperature a second time.
Sources and related decision models
Read on October 9, 2026: Perplexity’s model card, config.json, checkpoint files and decision_config.json. The weight total sums all 11 model shards and readout.safetensors.
Compare with LiquidAI d1-omni, the smaller text, image and audio decision model, or Laya for text-only decisions. How we distinguish estimates from measurements.
Frequently asked questions
How much VRAM does pplx-decider v1.1 need?
The published BF16 checkpoint is 52,173,413,928 bytes, or 48.59 GiB, including readout.safetensors. This is the weight footprint, before CUDA buffers, activations and input-dependent working memory. Perplexity asks for room for roughly 49 GiB of weights plus working memory.
Can it run on an RTX 4090, RTX 5090 or a 48 GB GPU?
The original BF16 weights alone exceed 24, 32 and 48 GiB. An 80 GiB CUDA GPU has room for the checkpoint, but peak memory still depends on input length, image size and batching. This page does not claim a measured peak or a validated quantized runtime.
Can I serve it as an ordinary chat model?
The checkpoint has a decision readout rather than a full vocabulary output head. Its saved full-attention layers are noncausal and its probabilities use a calibration temperature. A standard causal text-generation loader does not reproduce the evaluated model; use the included DecisionModel implementation.
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