Can you run Llama 3.1 8B Instruct on RTX 5080?

Llama 3.1 8B Instruct Q4_K_M on the NVIDIA GeForce RTX 5080: verdict, VRAM math and estimated speed.

VerdictYes, it runsA · 55
VRAM
16 GB(14.4 usable)
Model weights
6.5 GBQ4_K_M
Decode speed
est. 138 tok/stypical error 5%
First token
~0.2s
Quick answer

Yes, the NVIDIA GeForce RTX 5080 runs Llama 3.1 8B Instruct. 6.5 GB weights at Q4_K_M vs 14.4 GB usable VRAM; est. 138 tok/s, typical error 5% (ModelFit, 2026).

$ollama run llama3.1:8b-instruct-q4_K_M
Verdict
Comfortable
Decode speed
est. 138 tok/s, typical error 5%
Weights
6.5 GB Q4_K_M

VRAM math and speed are ModelFit engine estimates, not measurements. Typical error: the median gap between the ModelFit speed model and measured runs on hardware the model was not fitted on, for this backend and model size. Commands are registry-verified Ollama tags.

Cite this page: ModelFit, Llama 3.1 8B Instruct on RTX 5080, https://modelfit.io/can-i-run/llama3.1-8b-q4-on-rtx-5080/, updated November 2026, CC BY 4.0.

What limits this combo

The four constraints the fit engine checks for Llama 3.1 8B Instruct on the RTX 5080, in order of what usually breaks first.

Weights fit
OK6.5 GB of weights against 14.4 GB usable, leaving 7.9 GB of headroom for context and the runtime.
Context ceiling
OKWeights + KV cache stay in budget up to 32k tokens (10.5 GB total). Quantizing the KV cache to q8_0 roughly halves the KV column and pushes this further.
Speed
OKest. 138 tok/s, typical error 5% on 960 GB/s of memory bandwidth, comfortable for interactive chat and agentic loops.
Use-case ceiling
TightStrongest fit: Chat (A). Agentic coding caps at C, either the speed floor or the model's tuning is the limit; see the workload table for the per-case reason.
Table 1

Where the RTX 5080 sits for Llama 3.1 8B Instruct

On the RTX 5080, Llama 3.1 8B Instruct runs with room to spare (est. 138 tok/s, typical error 5%). The smallest card that also runs it comfortably is the RTX 4060 (8 GB, est. 43 tok/s, typical error 5%). Context ceiling on this card: 32k; on the RTX 4060: ~5k.

CardVRAMUsableVerdictDecode speedMax context
RTX 40608 GB7.2 GBYesest. 43 tok/s~5k
RTX 306012 GB10.8 GBYesest. 52 tok/s32k
RTX 407012 GB10.8 GBYesest. 77 tok/s32k
RTX 4060 Ti16 GB14.4 GBYesest. 45 tok/s32k
RTX 4070 Ti SUPER16 GB14.4 GBYesest. 99 tok/s32k
RTX 5070 Ti16 GB14.4 GBYesest. 131 tok/s32k
RTX 5080 (this card)16 GB14.4 GBYesest. 138 tok/s32k
RTX 309024 GB21.6 GBYesest. 123 tok/s64k
RTX 409024 GB21.6 GBYesest. 139 tok/s64k
RTX 509032 GB28.8 GBYesest. 222 tok/s128k

Same engine as the verdict above: 90% of VRAM usable, KV-cache at fp16, decode speed from the ModelFit speed model, typical error 5%. What typical error means. Verdicts of the other cards are computed for Llama 3.1 8B Instruct Q4_K_M exactly.

Table 2ModelFit engine estimate

Quant explorer

Switch between the quality-gated builds tracked for this exact combo. Q4_K_M stays the default recommendation; heavier Q6/Q8 builds only appear when their exact Ollama tags are registry-verified.

QuantLoadVerdictFitSpeedFirst tokenSafe contextRun
6.5 GBRunsA · 55 Excellent headroomest. 138 tok/stypical error 5%~0.2s · Instant32k
8 GBRunsA · 44 Excellent headroomest. 90 tok/stypical error 5%~0.9s · Instant32k
8 GBRunsA · 44 Excellent headroomest. 124 tok/stypical error 5%~0.3s · Instant32k

Why no 2-bit builds: Q1/Q2-class quants can look attractive in a memory table, but their quality loss is large enough that ModelFit excludes them from rankings instead of inflating the catalog with junk options. Usable VRAM: 14.4 GB.

Workload verdicts

ModelFit engine estimate

Llama 3.1 8B Instruct on the RTX 5080, graded per use case from the model's registry-verified tuning and the engine's speed estimate for this exact combo (est. 138 tok/s, typical error 5%).

Chat
Aest. 138 tok/s vs ~20 needed for chat.
Coding
Aest. 138 tok/s vs ~15 needed for coding.
Agentic coding
Cest. 138 tok/s vs ~30 needed for agentic coding; not tuned for tool-calling loops.
Reasoning
Cest. 138 tok/s vs ~12 needed for reasoning; not a reasoning-tuned model.
RAG
Aest. 138 tok/s vs ~20 needed for rag.

Grades combine tag-verified tuning (a model not built for the workload caps at C) with the tok/s floor each workload needs to feel usable. A combo that partially offloads caps at C; one that does not fit is D everywhere.

Memory math: weights + context vs budget

Weights take 6.5 GB. Context costs extra KV-cache on top; this is where long-context sessions break on cards that technically fit the weights.

Weights 6.5 GBKV cache · 16k context 2.0 GBHeadroom 5.9 GBRuntime reserve 1.6 GB

The model leaves about 5.9 GB of the usable VRAM budget free after weights and 16k context.

Table 3KV-cache by context length
ContextKV-cacheTotalFits
8k tokens1.0 GB7.5 GBFits
16k tokens2.0 GB8.5 GBFits
32k tokens4.0 GB10.5 GBFits
64k tokens8.0 GB14.5 GBOver
128k tokens16.0 GB22.5 GBOver

KV-cache figures assume an fp16 cache, the llama.cpp/Ollama default. Standard GQA models use a size-class estimate (8 KV heads x 128 head dim class); hybrid linear-attention models (Qwen3.5/3.6, Qwen3-Next) use the exact per-token cost from their published config, since only their sparse full-attention layers cache KV. A q8_0 KV cache roughly halves either figure. Estimates, not measurements.

See how fast it feels

Llama 3.1 8B Instruct: ~0.2s to start, then est. 138 tok/s, typical error 5%.

zsh · ollama run llama3.1:8b-instruct-q4_K_Mest. 138 tok/s

~ $ ollama run llama3.1:8b-instruct-q4_K_M

# Press Send to run the fixed message below.

# fixed message, the same for every model

>>> Summarize these meeting notes in one short paragraph: what was decided, and who does what next.

[meeting-notes.txt]
Weekly sync, support tools team
Attendees: Maya (lead), Jonas, Priya, Tom, Elena
Agenda: local drafting assistant pilot, knowledge base cleanup, customer feedback survey, on-call rota, next steps

1. Local drafting assistant pilot
- Maya recapped the goal: agents draft replies with an assistant that runs on the team's own Macs, so customer emails never leave the building and nothing depends on an outside service being up.
- Jonas ran the pilot for two weeks on four machines. Agents used it for first drafts on roughly a third of tickets. Most drafts needed light edits. A few needed a full rewrite, mostly billing questions where the model guessed at policy instead of saying it did not know.
- Priya said the biggest complaint was the wait before the first word on long tickets. Short tickets felt instant. Tickets with a long email thread pasted in took several seconds before anything appeared, and agents read that as the tool being stuck. Two agents restarted the app because of it.
- Tom suggested trimming the thread to the last three messages before sending it to the model. Elena worried that would drop context the customer refers back to, like an order number from the first email. Agreed to test both on the same set of tickets before choosing.
- Jonas said the speed once the reply starts was fine on every machine. Agents read slower than the model writes, so nobody asked for faster output. The only request was a visible sign that the model is reading, so people stop restarting it.
- Memory: the oldest machine, the one with the least memory, could not keep the model loaded next to the browser and the ticketing app. It swapped and slowed down badly by mid-morning. The other three machines had no issue all day.
- Priya asked whether a larger model would fix the billing guesses. Jonas thought not: the model guesses because the policy text it needs is missing or contradictory, and a bigger model would guess more fluently, not less.
- Decision: keep the current model size for now. Revisit only after the knowledge base cleanup, and only if the edit rate on billing drafts is still high.

2. Knowledge base cleanup
- Elena found about forty articles that contradict each other on refund windows and plan changes. These are the likely source of the billing guesses.
- Priya proposed one owner per section, with a review date on every article so stale pages show up on their own instead of during an angry ticket.
- Agreed: Elena owns billing and refunds, Priya owns accounts and login, Tom owns shipping and returns. Each owner archives duplicates, merges the rest, and flags anything that needs a policy decision from Maya.
- Jonas will add the cleaned articles to the assistant's reference folder once each section is signed off, not before. Mixing old and new versions would make the guessing worse.
- Tom asked for a template for new articles. Elena will share the one billing already uses.

3. Customer feedback survey
- Priya shared the quarterly survey results. Response time scores went up since the last quarter, and the free-text comments mention faster first replies more than once.
- Several comments still complain about being asked for the same order details twice. Elena thinks this happens when a ticket moves between agents and the notes field is left empty.
- Agreed: the handover checklist gets one new line, fill in the notes field before reassigning a ticket. Tom will update the checklist and post it in the team channel.
- Maya wants the next survey to ask one question about reply quality, not only speed, so the team can see whether the assistant drafts change how customers rate answers.

4. On-call rota
- Two people asked to swap weeks in November. Maya approved both swaps.
- Tom raised that weekend coverage gets thin when two people are on leave at the same time. Agreed that leave requests go in the team channel at least two weeks ahead, and Maya checks the rota before approving.
- No change to escalation rules. The escalation doc is still correct.

5. Next steps
- Jonas: run the trimmed thread versus full thread test on fifty past tickets and report the wait before the first word and the edit rate for each.
- Jonas: add a reading indicator to the assistant panel so agents can see the model is working on a long ticket.
- Elena, Priya, Tom: finish their knowledge base sections and send Maya the open policy questions.
- Maya: ask IT whether the oldest machine can get more memory or should be replaced at the next refresh.
- Everyone: log any draft that invents a policy, with the ticket link, in the shared sheet.
- Next sync: same time next week. Maya sends the agenda the day before.

Estimated speed, not a benchmark. Model loading excluded.

FAQ

Llama 3.1 8B Instruct on RTX 5080: FAQ

Can the NVIDIA GeForce RTX 5080 run Llama 3.1 8B Instruct?

Yes. Llama 3.1 8B Instruct (Q4_K_M) loads in about 6.5 GB and the RTX 5080 offers 14.4 GB of usable VRAM, leaving headroom for context. Expect est. 138 tok/s, typical error 5%.

How much VRAM does Llama 3.1 8B Instruct need?

About 6.5 GB for the weights at Q4_K_M, plus KV-cache for context: roughly 2.0 GB extra at 16k tokens. The RTX 5080 budget is 14.4 GB (16 GB x 90%).

What is the best quantization of Llama 3.1 8B Instruct for the RTX 5080?

The Q5_K_M build is the highest quality that fits (8 GB vs 14.4 GB usable). The Q4_K_M build at 6.5 GB leaves more room for long context.

What GPU do I need to run Llama 3.1 8B Instruct comfortably?

The RTX 5080 already runs Llama 3.1 8B Instruct comfortably. Larger cards only buy you longer context or a heavier quant.

How much context can Llama 3.1 8B Instruct use on the RTX 5080?

Up to 32k tokens stay fully in VRAM (10.5 GB total with the KV cache). At 64k tokens the total reaches 14.5 GB and tips over the budget. Quantizing the KV cache to q8_0 roughly halves the KV column and buys back about one context tier.

Is Llama 3.1 8B Instruct on the RTX 5080 fast enough for coding agents?

Barely on paper: the engine puts it at est. 138 tok/s, typical error 5% against the ~30 tok/s an agentic loop needs to feel responsive, but Llama 3.1 8B Instruct is not tuned for tool-calling, which caps its agentic grade; a coding-tuned model is the better pick here.

Llama 3.1 8B Instruct on other hardware

Other models on the RTX 5080