FLAN-T5-XXL (Text-Encorder only)

FLAN-T5-XXL (Text-Encoder Only)

Guide (External Site): English | Japanese

Why Use FP32 Text Encoder? (External Site): English | Japanese

Hugging Face

The FP8 and GGUF format is distributed as a compressed ZIP file. Please unzip it using any decompression software of your choice before use, or download from Hugging Face page.

FLAN-T5-XXL is a fine-tuned version of T5-XXL v1.1, designed to improve accuracy and performance.

The original FLAN-T5-XXL model is available on Google's Hugging Face page .

When used with Flux.1, SD3.5 and HiDream, replacement for T5-XXL v1.1 to FLAN-T5-XXL offers improved prompt comprehension and enhanced image quality .

This model has been streamlined by extracting only the text encoder portion, making it optimized for image generation workflows.

Model Variants

FP32

Full precision, highest quality — largest file size and heaviest VRAM/compute footprint. Best for archival or when maximum fidelity matters more than speed.

FP16

Half precision with virtually no perceptible quality loss for most use cases. The recommended default — a solid balance of accuracy and file size.

INT8_ConvRot_HQ

Lightweight 8-bit quantization using rotation-based conversion, preserving unusually high accuracy despite the reduced size. Great if you want INT8-level savings without the usual quality trade-off.

MXFP8 / FP8_svd_scaled / FP8

⚠️ Currently not recommended. These FP8 variants are kept for compatibility/testing but show degraded quality or stability compared to the other options — use INT8_ConvRot_HQ instead.

GGUF (Q8_0 / Q6_K / Q5_K_M / Q4_K_M)

Excellent compression ratios for constrained environments. Quality scales down the quantization ladder (Q8_0 closest to full precision, Q4_K_M smallest but with more quality loss) — pick based on your available memory.

Comparisons

FLAN-T5-XXL vs T5-XXL v1.1

FLAN-T5-XXL FP32 vs FP16 and Quantization

INT8_ConvRot vs FP8 (Other Model)

Tip: Upgrade CLIP-L Too

For even better results, consider pairing FLAN-T5-XXL with an upgraded CLIP-L text encoder:

LongCLIP-SAE-ViT-L-14 (ComfyUI only)

CLIP-SAE-ViT-L-14

Combining FLAN-T5-XXL with an enhanced CLIP-L model can further boost image quality.

License

Apache 2.0

This model is based on Google's FLAN-T5-XXL, also licensed under Apache 2.0.

Update History

2026.7.10

Upload INT8_ConvRot_HQ

2025.6.24

Re-upload of the GGUF model, reduction in model size, and correction of metadata.