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RX 7900 XT 20GB vs V100 16GB PCIe for Local LLMs

The V100 16GB PCIe has about 12% more memory bandwidth (900 vs 800 GB/s). Batch-1 decode tracks bandwidth closely, so a model that fits both cards should decode roughly 12% faster on the V100 16GB PCIe. The RX 7900 XT 20GB fits more of the catalog at Q4/8K — 31 vs 25 of 73 models (20 vs 16 GB VRAM). Largest model that fits the RX 7900 XT 20GB but not the V100 16GB PCIe: gemma-4-31B-it (30.7B). MSRP is $899 for the RX 7900 XT 20GB vs $8,000 for the V100 16GB PCIe. MSRP is a launch list price, not live retail — Amazon prices move; click through for the current price. Not retail-shoppable: V100 16GB PCIe (datacenter-class; cloud rental is the realistic way to use it). In the Q4/8K head-to-head below (49 shared models), the V100 16GB PCIe posts the higher tok/s in 31 rows vs 18. Methodology.

Spec comparison

RX 7900 XT 20GBV100 16GB PCIe
VendorAMDNVIDIA
VRAM20 GB16 GB
Memory typeGDDR6HBM2
Memory bandwidth800 GB/s900 GB/s
TDP315 W250 W
MSRP (list)$899$8,000
BuySearch Amazon · eBay · Newegg · B&H Photo

MSRP is the launch list price, not live retail. Buy links are Amazon affiliate links — the price after you click is the live price.

Q4 / 8K head-to-head — top 15 of 49 shared models

ModelParams (B)RX 7900 XT 20GB tok/sRX 7900 XT 20GB fitsV100 16GB PCIe tok/sV100 16GB PCIe fitsWinner
MiniCPM5-1B1.08554.6 est.Yes895.6 est.YesV100 16GB PCIe
Qwen3.5-2B2.0299.5 est.Yes483.6 est.YesV100 16GB PCIe
Qwen3.5-35B-A3B34.7472.2 est.No339.8 est.NoRX 7900 XT 20GB
Ornith-1.0-35B35.0464.4 est.No334.2 est.NoRX 7900 XT 20GB
qwen35b-a3b-fable-sft-abliterated34.7451.9 est.No325.2 est.NoRX 7900 XT 20GB
Qwen3.6-35B-A3B36.0440.3 est.No316.9 est.NoRX 7900 XT 20GB
GLM-4.7-Flash31.2434.9 est.No313.0 est.NoRX 7900 XT 20GB
Nemotron-3-Nano-Omni-30B-A3B-Reasoning-BF1630.0199.7 est.Yes434.0 est.NoV100 16GB PCIe
DeepSeek-R1-0528-Qwen3-8B-layer-mix-bpw-3.8-mlx2.3260.4 est.Yes420.5 est.YesV100 16GB PCIe
Qwen3-30B-A3B-Instruct-250730.5199.7 est.Yes405.4 est.NoV100 16GB PCIe
Llama-3.2-3B-Instruct3.2131.2 measuredYes302.3 est.YesV100 16GB PCIe
gpt-oss-20b21.5166.4 est.Yes268.7 est.YesV100 16GB PCIe
gemma-4-26B-A4B-it25.2157.6 est.Yes254.5 est.YesV100 16GB PCIe
Qwen3-4B-Instruct-25074.0149.7 est.Yes241.8 est.YesV100 16GB PCIe
NVIDIA-Nemotron-3-Nano-4B-BF164.0149.7 est.Yes241.8 est.YesV100 16GB PCIe

est. = bandwidth-based estimate; measured = curated real benchmark that overrides the estimate. Fits = weights + KV(8K) + 1 GB overhead ≤ 95% of VRAM.

Fit coverage at Q4 / 8K

RX 7900 XT 20GBV100 16GB PCIe
Catalog models that fit31 of 7325 of 73
Largest exclusive fitgemma-4-31B-it (30.7B)

RX 7900 XT 20GB details → · V100 16GB PCIe details →