Which quant should I download?

Prefer the shopper UD-Q4_K_XL file when it still fits. Q6 / Q5 / Q4 are the listed shopper steps. UD-Q3_K_XL is a labeled estimate — not a house pick. Q1/Q2 stay off. See Quants, Q6 / Q5 / Q4 + Q3 estimate.

Measured decode is only the official local desktop 35B llama.cpp Vulkan sweep on one or two R9700s. Every other model × card stays not measured yet. Record a card with amdai-bench. See Contribute, amdai-bench, Benchmarks.

Can my Radeon run it? · RX 7900 XT · Qwen 3.8 Flash · llama.cpp

Can RX 7900 XT run Qwen 3.8 Flash?

Fits with RAM offload

RX 7900 XT (20 GB) × Qwen 3.8 Flash. Shopper file is UD-Q4_K_XL at 256K. Calculator verdict: fits with ram offload. llama.cpp first (Vulkan, then HIP). Q3 is a labeled estimate, not a house pick. Measured decode appears only where a local desktop card already exists. We do not invent a price.

Full requirements at 256K

Next step

Your next step for this model: 128 GB DDR5 for the offloaded experts.

Return terms vary by seller and item. Newegg's Hassle-Free page covers only Sold-and-Shipped-by-Newegg listings; marketplace items use the seller's policy. See the listing's Warranty & Returns tab.

A commission does not change the fit verdict on this page. We do not print a price.

As an Amazon Associate I earn from qualifying purchases. Some Newegg links use Rakuten Advertising and some B&H links use B&H’s affiliate program when those IDs are configured. Micro Center and AMD Store links are plain “also available at” links — no tracking. Buttons say “Check price” and never invent or live-quote a price. Full disclosure.

How we test — Measured cells cite official amdai-bench/run@1 cards. Estimates stay labeled. Q3 is estimate-only. Q1/Q2 stay off.

Q6 / Q5 / Q4 plus a Q3 estimate

Weights are official GGUF listings when the model page has them. Totals include KV at f16. 1-GPU and 2-GPU columns use the same calculator as this share URL.

Qwen 3.8 Flash on RX 7900 XT fit table
Quant	Weights	1× 4K	1× 32K	1× 256K	2× 4K	2× 32K	2× 256K	Speed
UD-Q6_K_XL Estimate	157.4 GB Hugging Face folder listing for UD-Q6_K_XL (~169 GB across 6 shards)	Does not fit this GPU 160.4 GB	Does not fit this GPU 161.2 GB	Does not fit this GPU 167.9 GB	Does not fit this GPU 80.2 GB/GPU	Does not fit this GPU 80.6 GB/GPU	Does not fit this GPU 83.9 GB/GPU	not measured yet No official local desktop cell for this model × card. Empty stays not measured yet. Contribute · amdai-bench
UD-Q5_K_XL Estimate	147.4 GB Unsloth docs listing for UD-Q5_K_XL (158.3 GB). Hugging Face folder lists 158 GB across 6 shards (retrieved 2026-10-13)	Does not fit this GPU 150.3 GB	Does not fit this GPU 151.1 GB	Does not fit this GPU 157.8 GB	Does not fit this GPU 75.1 GB/GPU	Does not fit this GPU 75.6 GB/GPU	Does not fit this GPU 78.9 GB/GPU	not measured yet No official local desktop cell for this model × card. Empty stays not measured yet. Contribute · amdai-bench
UD-Q4_K_XL Estimate	103.4 GB Hugging Face folder listing for UD-Q4_K_XL (~111 GB across 4 shards). Unsloth docs list 111.3 GB (retrieved 2026-10-13)	Does not fit this GPU 105.6 GB	Does not fit this GPU 106.4 GB	Does not fit this GPU 113.1 GB	Does not fit this GPU 52.8 GB/GPU	Does not fit this GPU 53.2 GB/GPU	Does not fit this GPU 56.5 GB/GPU	not measured yet No official local desktop cell for this model × card. Empty stays not measured yet. Contribute · amdai-bench
UD-Q3_K_XL Q3 estimate	83.8 GB Hugging Face folder listing for UD-Q3_K_XL (~90 GB across 3 shards; LFS sizes sum 89.99 GB)	Does not fit this GPU 85.7 GB	Does not fit this GPU 86.5 GB	Does not fit this GPU 93.2 GB	Does not fit this GPU 42.9 GB/GPU	Does not fit this GPU 43.3 GB/GPU	Does not fit this GPU 46.6 GB/GPU	not measured yet UD-Q3_K_XL is a labeled estimate — not a local desktop run. Contribute · amdai-bench

System RAM

When the file does not stay in 20 GB VRAM, the spill is system RAM. Shopper lines stay Minimum system RAM needed and RAM needed at full context for UD-Q4_K_XL on this card. Estimate unless a measured R9700 card overlays the kit.

Minimum system RAM needed

128 GB kit

Estimate · 117.1 GiB raw · 256K context

RAM needed at full context

128 GB kit

Estimate · 117.1 GiB raw · 256K full context

Estimate. Offloaded weights + KV in RAM + runtime + OS/desktop + headroom, rounded up to a 128 GB DIMM kit.

Breakdown

Offloaded weights ·: 83.4 GiB
Separable embed in RAM ·: 0 GiB
KV in RAM at selected ·: 7.61 GiB
KV in RAM at full context ·: 7.61 GiB
Runtime / backend ·: 2.06 GiB
OS / desktop baseline ·: 8.00 GiB
Headroom ·: 16.0 GiB

llama.cpp launch

Vulkan first, then ROCm/HIP. Copy a house recipe when one exists. llama.cpp stays first. Strata / vLLM stay on /backends.

llama.cpp Vulkan

llama.cpp first (Flash)

Flash shopper is UD-Q4_K_XL at 262K. Two 32 GB cards plus 96 GB DDR5 is the house path. The GGUF is a sharded folder — do not invent a single filename.

# llama.cpp Vulkan. House pin when a recipe exists; otherwise a shape only.
./build-vk/bin/llama-server \
  -m ~/models/UD-Q4_K_XL/Qwen3.8-Flash-Next-UD-Q4_K_XL-00001-of-00004.gguf \
  -ngl 99 \
  -c 262144 \
  --cache-type-k f16 \
  --cache-type-v f16 \
  --host 127.0.0.1 --port 8080

llama.cpp HIP

ROCm / HIP after rocminfo

HIP decode is not measured yet. Confirm gfx with rocminfo first.

# HIP shape only — house 35B cards are Vulkan. HIP decode is not measured yet.
./build-hip/bin/llama-server \
  -m ~/models/UD-Q4_K_XL/Qwen3.8-Flash-Next-UD-Q4_K_XL-00001-of-00004.gguf \
  -ngl 99 \
  -c 262144 \
  --cache-type-k f16 \
  --cache-type-v f16 \
  --host 127.0.0.1 --port 8080

Same model, other cards

Qwen 3.8 Flash on the other published Radeon sheets.

Other models on RX 7900 XT

Check price

Existing /go/ routes for this GPU sheet. Buttons say Check price — we do not print a figure.

Check price · no live or invented prices

Radeon RX 7900 XT

Return terms vary by seller and item. Newegg's Hassle-Free page covers only Sold-and-Shipped-by-Newegg listings; marketplace items use the seller's policy. See the listing's Warranty & Returns tab.

FAQ

Can RX 7900 XT run Qwen 3.8 Flash?: Fits with RAM offload on the calculator at the shopper UD-Q4_K_XL file and 256K. Q6 / Q5 / Q4 are listed. UD-Q3_K_XL is a labeled estimate. llama.cpp first.; This pair · RX 7900 XT · Qwen 3.8 Flash · Calculator · Full requirements at 256K
Which quant should I download?: Prefer the shopper UD-Q4_K_XL file when it still fits. Q6 / Q5 / Q4 are the listed shopper steps. UD-Q3_K_XL is a labeled estimate — not a house pick. Q1/Q2 stay off.; Quants · Q6 / Q5 / Q4 + Q3 estimate
How fast is it?: Measured decode is only the official local desktop 35B llama.cpp Vulkan sweep on one or two R9700s. Every other model × card stays not measured yet. Record a card with amdai-bench.; Contribute · amdai-bench · Benchmarks

Stack Lab

Measure the pair on your box. Doctor and planner are allowlisted. House daily / Flash profiles appear only for those house models.

Open in Stack Lab

If the app is not installed, packages are not published yet. There is no public download URL. Read the Stack Lab install notes . If Stack Lab is already running on this machine, open the local app .

Open in Stack Lab

If the app is not installed, packages are not published yet. There is no public download URL. Read the Stack Lab install notes . If Stack Lab is already running on this machine, open the local app .

Open in Stack Lab

If the app is not installed, packages are not published yet. There is no public download URL. Read the Stack Lab install notes . If Stack Lab is already running on this machine, open the local app .

Open in Stack Lab

If the app is not installed, packages are not published yet. There is no public download URL. Read the Stack Lab install notes . If Stack Lab is already running on this machine, open the local app .

Also: All pairs · RX 7900 XT · Qwen 3.8 Flash · Official GGUF · Official card · llama.cpp · Speed up llama.cpp · Dual / multi-GPU

Next steps

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Topics New measured run cards Official amdai-bench/run@1 cards as they land on /results. Guides and tutorials New or updated getting-started notes, tutorials, and blog posts. ROCm problem updates Cited /rocm-problems rows when status or workaround changes. Stack Lab releases Radeon Stack Lab companion notes — Ubuntu 24.04+, packages not published yet.