RTX 4070 12GB vs RTX 5070 12GB for local LLMs
Memory fit, speed and context compared with the same math as the advisor. Both offer about the same usable memory (11.0 GB), so the difference is mostly bandwidth (504 vs 672 GB/s).
Verdict from the numbers
- Fit. RTX 4070 12GB fits 4 of 13 models fully at 16k context (largest: Gemma 4 12B Q6_K); RTX 5070 12GB fits 4 (largest: Gemma 4 12B Q6_K). Both fit the same set of models.
- Speed. On the 4 models that fit fully on both, RTX 5070 12GB is faster by a typical 1.3x. RTX 4070 12GB is ahead on 0, RTX 5070 12GB on 4. 2 of those comparisons use measured speeds on both sides; the rest involve at least one estimate (see the badges).
- Trade-off. Both offer about the same usable memory (11.0 GB), so the difference is mostly bandwidth (504 vs 672 GB/s).
Where to check prices
Price tier note
We do not list prices because they move daily and differ between new and used stock. What the data does show is what the memory difference buys: both have the same usable memory, so model fit is identical and the choice comes down to speed (504 vs 672 GB/s bandwidth). Use the Amazon links above to compare current listings and decide whether the difference is worth it for the models you want to run.
Model by model · 16k context, f16 KV cache
| Model | RTX 4070 12GB fit | tok/s | RTX 5070 12GB fit | tok/s | Faster / fits |
|---|---|---|---|---|---|
| Gemma 4 26B-A4B UD-Q4_K_M | MoE offload to CPU | 46 estimated | MoE offload to CPU | 48 estimated | - |
| Gemma 4 31B Q4_K_M | partial offload (slow) | 6 estimated | partial offload (slow) | 6 estimated | - |
| Gemma 4 12B Q6_K | fits fully | 43 scaled from measured | fits fully | 51 scaled from measured | RTX 5070 12GB |
| Qwen3.6 27B Q4_K_M | partial offload (slow) | 7 estimated | partial offload (slow) | 7 estimated | - |
| Qwen3.6 35B-A3B UD-Q4_K_M | MoE offload to CPU | 49 estimated | MoE offload to CPU | 50 estimated | - |
| Qwen3.5 9B Q8_0 | fits fully | 51 measured | fits fully | 68 measured | RTX 5070 12GB |
| Qwen3.5 4B Q8_0 | fits fully | 89 measured | fits fully | 116 measured | RTX 5070 12GB |
| gpt-oss 20B Q4_K_M | MoE offload to CPU | 121 estimated | MoE offload to CPU | 132 estimated | - |
| gpt-oss 120B | does not fit | - | does not fit | - | - |
| Qwen3-Coder 30B-A3B Q4_K_M | MoE offload to CPU | 47 estimated | MoE offload to CPU | 48 estimated | - |
| Mistral Small 3.2 24B Q4_K_M | partial offload (slow) | 8 estimated | partial offload (slow) | 9 estimated | - |
| Qwen3-VL 8B Q6_K | fits fully | 62 scaled from measured | fits fully | 74 scaled from measured | RTX 5070 12GB |
| GLM-4.5-Air | does not fit | - | does not fit | - | - |
Badges: measured medians of real llama.cpp runs; scaled from measured and estimated come from our bandwidth model. See sources and methods.
How much context fits?
Largest context where weights plus KV cache stay inside usable memory, per model that fits fully on at least one side. q8_0 KV roughly halves the cache.
| Model | RTX 4070 12GB f16 | RTX 5070 12GB f16 | RTX 4070 12GB q8_0 | RTX 5070 12GB q8_0 |
|---|---|---|---|---|
| Gemma 4 12B | 32k | 32k | 64k | 64k |
| Qwen3.5 9B | 32k | 32k | 64k | 64k |
| Qwen3-VL 8B | 16k | 16k | 32k | 32k |
| Qwen3.5 4B | 128k | 128k | 256k | 256k |
Spec summary
| RTX 4070 12GB | RTX 5070 12GB | |
|---|---|---|
| Usable memory for model + KV cache | 11.0 GB | 11.0 GB |
| Memory bandwidth | 504 GB/s | 672 GB/s |
| Models that fit fully at 16k | 4 of 13 | 4 of 13 |
| Models that need offload or do not fit | 9 | 9 |
| Measured data points on file | 11 | 11 |
FAQ
Which is faster for local LLMs, RTX 4070 12GB or RTX 5070 12GB?
On the 4 models that fit fully on both, RTX 5070 12GB is typically 1.3x faster (geometric mean). RTX 4070 12GB wins 0 and RTX 5070 12GB wins 4. 2 comparisons are measured on both.
Which fits more models, RTX 4070 12GB or RTX 5070 12GB?
RTX 4070 12GB fits 4 of 13 models fully at 16k context and RTX 5070 12GB fits 4.
Can I run long context on RTX 4070 12GB or RTX 5070 12GB?
At f16 KV cache, the largest-model context limits are in the table above (for example Gemma 4 12B on RTX 4070 12GB: 32k; Gemma 4 12B on RTX 5070 12GB: 32k). A q8_0 KV cache extends it further.
Do you state prices for RTX 4070 12GB or RTX 5070 12GB?
No. Prices change daily, so we link to Amazon search results instead and focus on measured and estimated speed and memory fit.
Related
RTX 4070 12GB · RTX 5070 12GB · Measured model pages: Qwen3.5 9B · Gemma 4 12B
By memory: 8 GB · 12 GB · 16 GB · 24 GB · 32 GB · 48 GB · 64 GB · 96 GB · 128 GB · 192 GB · 256 GB · 512 GB