Guide
Dual RTX 3090 build for 70B
One 24 GB card does not fully hold Llama 3.3 70B at Q4 in this formula. The dual RTX 3090 row does. The euro amount is the catalog figure, not a shop listing. USD is an FX estimate.
The row in the catalog
Dual RTX 3090, 48 GB: $2,217 (USD is an FX estimate), €1,980 incl. VAT. Global prices (USD), EUR available. Marked used. price unverified. sourceUrl is null. Dated 2026-10-14.
Parts: 2× GeForce RTX 3090 24GB, used; Ryzen 9 5900X or similar; 128 GB DDR4; 1200W PSU, a case that can breathe. Combined TDP in the catalog is 700 W. That describes the row. It is not a power measurement. Dual RTX 3090, 48 GB lists 48 GB and 1872 GB/s. bandwidthEstimated is false, but bandwidthSourceUrl is null, so that speed is not a citation.
Why one card is not enough
Llama 3.3 70B Q4 at 8,192 tokens is 43.0 GB in this formula (39.5 GB weights, 2.7 GB KV cache, 0.8 GB overhead). Fit on GeForce RTX 3090 24GB: not a fit. Fit on Used PC with RTX 3090 24GB: offload only, not a full fit. Fit on Dual RTX 3090, 48 GB: a full fit (usable 45.6 GB across 48 GB).
Dual RTX 3090, 48 GB has 45.6 GB usable after the reserve in this formula (catalog memory 48 GB, vram). The reserve is 1.2 GB per card. Qwen2.5 32B Q4 at 8,192 tokens is 21.3 GB in this formula (18.4 GB weights, 2.1 GB KV cache, 0.8 GB overhead) already fits one 3090 PC: a full fit. The second card is for the 70B class.
What the speed estimate is not
The catalog lists 1872 GB/s for the pair (936 GB/s on each of 2 cards). bandwidthSourceUrl is null. The methodology multiplies multi-GPU bandwidth by 0.8 because a layer split does not add bandwidth. That factor is an assumption. Tokens per second on the calculator are estimates from the methodology page. benchmarkSourceUrl stays null. This guide does not add a measured llama-bench result.
The price is still unverified
- GeForce RTX 3090 24GB: $806 (USD is an FX estimate), €720 incl. VAT. Global prices (USD), EUR available. Marked used. price unverified. sourceUrl is null. Dated 2026-10-14.
- Used PC with RTX 3090 24GB: $1,433 (USD is an FX estimate), €1,280 incl. VAT. Global prices (USD), EUR available. Marked used. price unverified. sourceUrl is null. Dated 2026-10-14.
- Dual RTX 3090, 48 GB: $2,217 (USD is an FX estimate), €1,980 incl. VAT. Global prices (USD), EUR available. Marked used. price unverified. sourceUrl is null. Dated 2026-10-14.
sourceUrl is null on each of those rows. The date is the catalog asOf field. This page does not add a shop listing.
Open the calculator: Llama 3.3 70B Q4 under €2,000. Hardware page: Dual RTX 3090, 48 GB.
Related: RTX 3090 vs 4090 for local LLMs, Used RTX 3090 buying guide (EU), How much VRAM does a 70B model need?.