RTX 4070 vs 3090 VRAM Comparison | Generated by AI
Question: Is it true that the RTX 4070 (12GB) has too little VRAM compared to the RTX 3090 (24GB), and is the price difference on JD.com around 2,000–3,000 RMB?
Answer: Yes, your assessment is largely accurate, especially if you are using the card for AI development, LLMs (Large Language Models), or high-resolution video editing.
While the RTX 4070 is a much newer and more power-efficient card, the 12GB VRAM is a significant bottleneck for specific professional workloads compared to the 24GB found on the RTX 3090.
1. The VRAM Factor: Why it matters
- AI & Deep Learning: If you are running local LLMs (like Llama 3) or Stable Diffusion with high-resolution “ControlNet” layers, 12GB will often trigger “Out of Memory” (OOM) errors. The 24GB on a 3090 allows you to run much larger models or higher batch sizes.
- Gaming: At 1440p, 12GB is plenty. However, at 4K with “Ultra” textures in modern titles, you may start to hit the limit, though the 4070 isn’t primarily a 4K powerhouse anyway.
2. Market Pricing (JD.com / China Market)
The price gap you mentioned (2,000–3,000 RMB) is the current “standard” for moving between these two tiers in the Chinese market:
- RTX 4070 (New): Generally stays in the ¥4,200 – ¥4,800 range depending on the brand.
- RTX 3090 (Used/Refurbished): Since the 3090 is no longer in mass production, “New” stock on JD is rare and overpriced. Most users look at “JD Second-hand” (京东二手) or specialized vendors where they go for ¥6,500 – ¥7,500.
- The Math: A price jump of roughly ¥2,000 - ¥2,500 to double your VRAM and gain ~10-15% raw rasterization performance is common.
3. Comparison Table
| Feature | RTX 4070 | RTX 3090 |
|---|---|---|
| VRAM | 12GB GDDR6X | 24GB GDDR6X |
| Architecture | Ada Lovelace (Newer) | Ampere (Older) |
| Power Draw | ~200W (Very Efficient) | ~350W+ (Requires beefy PSU) |
| Special Tech | DLSS 3 + Frame Gen | DLSS 2 |
| Best For | 1440p Gaming / Efficiency | AI / 4K Gaming / 3D Rendering |
Summary Recommendation
- Keep the 4070 if: You mostly play games, care about your electricity bill, and want a card with a full warranty.
- Switch to the 3090 if: You are serious about AI/Machine Learning or heavy 3D production. In those fields, VRAM is king, and no amount of “new architecture” can compensate for having half the memory.
References: