R9 M390X vs RX 6400
Head-to-head specifications
| Metric | R9 M390X | RX 6400 | Difference |
|---|---|---|---|
| 3DMark Time Spy | 1,435 | 1,499 | -4.3% |
| Avg FPS @ 1080p | 29 | 29 | — |
| Avg FPS @ 1440p | 16 | 16 | — |
| Avg FPS @ 4K | 8 | 8 | — |
| FP32 compute (TFLOPS) | 4.1 | 3.6 | +14.8% |
| VRAM | 4 GB GDDR5 | 4 GB GDDR6 | — |
| Memory bandwidth (GB/s) | 160 | 112 | +42.9% |
| TDP (W) | 125 | 53 | — |
- R9 M390X averages 16 fps at 1440p versus 16 fps — about 0% faster.
- RX 6400 draws less power (53W vs 125W).
Verdict: R9 M390X or RX 6400?
R9 M390X advantages
- Memory bandwidth (+30%)
RX 6400 advantages
- Synthetic benchmark performance (+4%)
- Power efficiency (+58%)
Which should you choose?
- Choose the R9 M390X if you work with high-resolution textures or memory-bound workloads.
- Choose the RX 6400 if you want the higher benchmark performance overall.
R9 M390X vs RX 6400: which should you choose?
R9 M390X — AMD desktop graphics card (2015, GCN 1.0) with 4 GB of GDDR5, averaging 16 fps at 1440p.
RX 6400 — AMD desktop graphics card (2022, RDNA 2) with 4 GB of GDDR6, averaging 16 fps at 1440p; launched at $159.
R9 M390X vs RX 6400: R9 M390X is faster for gaming. R9 M390X averages 16 fps at 1440p versus 16 fps — about 0% faster. RX 6400 draws less power (53W vs 125W).
1080p, 1440p and 4K
At 1440p — the most common enthusiast resolution — the R9 M390X averages 16 fps against 16. At 4K (8 vs 8 fps) VRAM (4GB vs 4GB) and memory bandwidth matter more.
Power and value
Board power is 125 W versus 53 W, which affects PSU headroom, case cooling and noise.
The verdict
Both are credible choices in the graphics card comparison space; the specification table above lays out every metric so you can weigh the trade-offs that matter to you. Pick the one whose strengths line up with how you will actually use it.
Frequently asked questions
Is the R9 M390X better than the RX 6400?
RX 6400 takes the overall edge, though R9 M390X wins in specific areas worth weighing. R9 M390X averages 16 fps at 1440p versus 16 fps — about 0% faster.
What is the main difference between the R9 M390X and the RX 6400?
R9 M390X averages 16 fps at 1440p versus 16 fps — about 0% faster. RX 6400 draws less power (53W vs 125W).
Which should I choose?
Choose the R9 M390X if you work with high-resolution textures or memory-bound workloads. Choose the RX 6400 if you want the higher benchmark performance overall.
Methodology
Graphics cards are compared on 3DMark Time Spy scores, average gaming frame rates at 1080p/1440p/4K, FP32 compute throughput, VRAM capacity and type, memory bandwidth, board power (TDP) and launch MSRP — plus AI workload throughput (Stable Diffusion iterations/s and local LLM tokens/s) where measured. Vintage and server GPUs without modern benchmark results are compared on specifications only, clearly labelled. Frame rates are averages across a game suite at high settings; specific titles vary.