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EleutherAI / gpt_neox

gpt-neox-20b

20.7 billion parameters.

Open in the calculator →

Architecturepublished data
Quick answer
gpt-neox-20b needs about 15.7 GB at Q4_K_M — the format most people download — with 2,048 tokens of context. It fits entirely on 17 of 18 common devices, starting with the AMD Radeon™ RX 9070 XT (16 GB). What else fits in 16 GB. No hardware for it? Rent a GPU that runs it, priced live.

Sized at 2,048 tokens of context with the whole model in device memory, across 18 common devices. Speeds are estimates, not benchmarks.

Find the AMD Radeon™ RX 9070 XT, the smallest card listed here that holds it: Amazon ↗ · eBay (new and used) ↗Store links may pay us a commission. They never decide which card is suggested — the memory arithmetic does.

Weight-file size by format

FormatSizeRangeBasis
FP1641.5 GB29.0 GB – 41.9 GBsize range
Q8_022.1 GB15.4 GB – 22.8 GBsize range
Q6_K17.0 GB11.9 GB – 17.9 GBsize range
Q5_K_M14.8 GB9.98 GB – 17.9 GBsize range
Q5_014.5 GB9.98 GB – 17.9 GBsize range
Q4_K_M12.7 GB8.17 GB – 17.9 GBsize range
Q4_012.1 GB8.17 GB – 17.9 GBsize range
Q3_K_M10.4 GB6.24 GB – 17.9 GBsize range
Q2_K8.21 GB4.76 GB – 17.9 GBsize range

A file size is not the memory a run needs: the KV cache and the runtime reserve come on top, and the calculator adds both.

What the labels mean
published data
Read from a published source — a file's byte count, a model's configuration or a manufacturer's specification — or exact arithmetic on such values. Not a measurement on a machine.
reconstructed size
Weight size reconstructed from the pinned architecture, because no published file exists.
size range
Only a lower and an upper bound are claimed for this weight size.

Hardware ladder

Q4_K_M at 2,048 tokens · 17 of 18 devices hold it entirely
DeviceMemoryVerdictDecodeCalculator
NVIDIA GeForce RTX 507015.7 GB of 12 GB13 layers on system RAM~9.1 tok/s with offloadOpen →
AMD Radeon™ RX 9070 XT15.7 GB of 16 GBfits~27 tok/sAbout reading paceOpen →
NVIDIA GeForce RTX 408015.7 GB of 16 GBfits~26 tok/sAbout reading paceOpen →
NVIDIA GeForce RTX 508015.7 GB of 16 GBfits~35 tok/sOpen →
NVIDIA GeForce RTX 5070 Ti15.7 GB of 16 GBfits~33 tok/sOpen →
NVIDIA GeForce RTX 5060 Ti 16GB15.7 GB of 16 GBfits~16 tok/sAbout reading paceOpen →
NVIDIA GeForce RTX 409015.7 GB of 24 GBfits~37 tok/sOpen →
AMD Radeon™ RX 7900 XTX15.7 GB of 24 GBfits~40 tok/sOpen →
NVIDIA GeForce RTX 309015.7 GB of 24 GBfits~34 tok/sOpen →
NVIDIA GeForce RTX 509015.7 GB of 32 GBfits~66 tok/sOpen →
NVIDIA RTX 6000 Ada Generation15.7 GB of 48 GBfits~35 tok/sOpen →
Apple M4 Pro15.7 GB of 64 GBfits~13 tok/sAbout reading paceOpen →
Apple M5 Pro15.7 GB of 64 GBfits~14 tok/sAbout reading paceOpen →
AMD Ryzen AI Max+ 395 with Radeon 8060S15.7 GB of 128 GBfits~11 tok/sAbout reading paceOpen →
Apple M3 Max15.7 GB of 128 GBfits~18 tok/sAbout reading paceOpen →
Apple M4 Max15.7 GB of 128 GBfits~24 tok/sAbout reading paceOpen →
NVIDIA DGX Spark15.7 GB of 128 GBfits~10 tok/sAbout reading paceOpen →
Apple M2 Ultra15.7 GB of 192 GBfits~33 tok/sOpen →

Decode is a calibrated estimate from the published calibration; capacity is the manufacturer's published ceiling, not guaranteed free memory. Fitting in memory is not the same as loading: whether the runtime and version you have supports this architecture and format on that machine has not been tested here. Offloaded rows assume there is enough system RAM for the overflow — the calculator checks that against the RAM you declare. Each “Open” link keeps this model, format and context.

Run it in the cloud

Rent a GPU that runs gpt-neox-20b

Every rentable machine that holds the whole model, from Vast.ai and RunPod, with this site's speed estimate for each and the provider's own price, read live. Cheapest first; sort by cost per token or speed instead, or switch the format.

Prices · 18:30 UTC, 22 Sept
27 configurations in stock · 6 out of stock
MachineSpeedPer hourPer M tokensWhereRent
1× RTX 4060 Ti 16GB16 GBcheapest~10 tok/sAbout reading pace$0.090$2.35Vast.aiMarketplace · 99.4% reliableRent on Vast.ai
2× RTX 306024 GB~26 tok/sAbout reading pace$0.11$1.14Vast.aiMarketplace · 98.0% reliableRent on Vast.ai
1× RTX 309024 GBrecommendedbest value~34 tok/sFaster than you read$0.12$0.99Vast.aiMarketplace · 99.5% reliableRunPod $0.50/h Rent on Vast.ai
1× RTX 5060 Ti 16GB16 GB~16 tok/sAbout reading pace$0.12$2.06Vast.aiMarketplace · 99.1% reliableRent on Vast.ai
1× RTX 3090 Ti24 GB~37 tok/sFaster than you read$0.19$1.41Vast.aiMarketplace · 99.6% reliableRunPod $0.27/h Rent on Vast.ai
2× RTX 407024 GB~37 tok/sFaster than you read$0.19$1.42Vast.aiMarketplace · 99.8% reliableRent on Vast.ai
1× RTX 5070 Ti16 GB~32 tok/sFaster than you read$0.20$1.71Vast.aiMarketplace · 99.9% reliableRent on Vast.ai
1× RTX 4080 SUPER16 GB~27 tok/sAbout reading pace$0.23$2.37Vast.aiMarketplace · 99.9% reliableRent on Vast.ai

First time renting a GPU? How it works, in four steps
  1. Create an account and add credit. Both providers are prepaid: $10 is enough to try any card on this page for hours. A new RunPod account that arrives through a referral link gets a one-time $5 credit when it first adds $10.
  2. Pick the card and the count shown here, and a template: llama.cpp or vLLM for an OpenAI-compatible API, or one with a web chat if you only want to talk to the model. “How to launch it” below gives the exact image and command.
  3. Wait for the download. The weights are fetched on the machine; tens of gigabytes take a few minutes on a data-centre connection. You pay by the second from the moment it starts.
  4. Stop it when you are done. A running machine bills even when idle. A stopped one costs nothing per hour, though its disk is usually still billed until you delete it.
How to launch it

No Q4_K_M file of gpt-neox-20b is catalogued here, so there is no exact command to vouch for. Start the machine from the llama.cpp server image ghcr.io/ggml-org/llama.cpp:server-cuda and point -hf at a Q4_K_M build from the publisher or a quantizer you trust — search Hugging Face for one. Check its file size against the memory figure on this page before you rent.

Every machine holds the whole model at Q4_K_M and 2,048 tokens of context, no offload. Speeds are this site’s single-stream decode estimates; prices are what each provider’s own API quoted, on-demand, for the whole machine. Vast hosts below 98% measured reliability are left out.

Referral links Vast.ai, RunPod and Novita pay us a share of what you spend if you sign up through these buttons. It costs you nothing, and it never decides an order or a recommendation: both are computed from the live price and the speed, and options that pay us nothing are listed and recommended on the same terms. How we rank

Buying a card instead, or paying by the token? Compare a year of gpt-neox-20b three ways →

Under the hood

Architecture, read from the publisher’s file

The numbers every figure above is computed from, with the file they came from.

Architecture

✓ Architecture read from the published config.json

Retrieved 2026-09-01 at pinned commit c292233c833e; parameter count from the safetensors index at the same revision.

Architecture
gpt_neox
Layers
44
Hidden size
6,144
Attention heads
64
Feed-forward width
24,576
Vocabulary
50,432
Context ceiling
2,048

Where the memory goes

tokenembedding× 44 decoder blocksMulti-head attentionhead counts not publishedfull contextFeed-forwardone networkall activeoutputprojectiongrows with contextfixed per token

Every attention head caches its own keys and values, so the KV cache grows at the full multi-head rate with context.

Open the exact official config.json ↗

More from EleutherAI

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Use this answer in your own product

As JSON, from the API
curl -s https://llmbottleneck.com/v1/analyze \
  -H "Authorization: Bearer $LLMB_KEY" -H "content-type: application/json" \
  -d '{"model":"eleutherai-gpt-neox-20b","quantization":"Q4_K_M","context":2048,"hardware":"nvidia-geforce-rtx-4090"}'

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On your page, as a widget
<script src="https://llmbottleneck.com/widget.js"
  data-model="eleutherai-gpt-neox-20b" data-quantization="Q4_K_M"
  data-hardware="nvidia-geforce-rtx-4090" data-context="2048"></script>

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Citing this page

LLM Bottleneck. “gpt-neox-20b VRAM and hardware requirements.” Architecture from EleutherAI/gpt-neox-20b at revision c292233c833e, retrieved 2026-09-01. https://llmbottleneck.com/models/eleutherai-gpt-neox-20b

Every figure above is either the published value or a reconstruction whose measured error is on the accuracy page.

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catalogue 2026-10-03models 327devices 135