Performance comparison: which is faster?
AMD Athlon II X4 645 (AMD, 2010) and AMD Athlon II X4 640 (AMD, 2010) are compared here. Compare not only scores, but also whether the motherboard can be reused and which GPU class is balanced with each CPU.
Overall performance: Athlon II X4 645 is about 6.1% faster
Both use the same AM3 socket, so they can be installed on the same motherboard. For games, performance balance with the GPU (guideline CPU:GPU = 0.9:1) matters more than CPU speed alone.
Relative performance score (higher is faster). Actual speed varies by workload, cooling, and memory configuration.
| Item | Athlon II X4 645 | Athlon II X4 640 |
|---|---|---|
| Performance Score | 3,500 | 3,300 |
| Generation | Athlon II | Athlon II |
| Socket | AM3 | AM3 |
| Release Year | 2010 | 2010 |
| Type | Desktop | Desktop |
| Compatible GPU Example | GeForce GTX 480 | Radeon HD 7850 |
| If You Want To... | Recommended |
|---|---|
| Prioritize maximum speed for heavy work or a high-end GPU | Athlon II X4 645 |
| Upgrade while reusing the current motherboard | Either works (same AM3 socket) |
| Prioritize value and adequate performance | Athlon II X4 640 (the lower model is often sufficient) |
Athlon II X4 645 is about 6.1% higher by score (Athlon II X4 645: 3500 points / Athlon II X4 640: 3300 points). For gaming, the GPU tier usually matters more than a few percent of CPU difference. For CPU-heavy work such as video editing and streaming, choose the faster CPU.
Both are Athlon II-generation CPUs.Both use the same AM3 socket, so they can be installed on the same motherboard.
Using our CPU:GPU = 0.9:1 guideline, GeForce GTX 480 pairs well with Athlon II X4 645 and Radeon HD 7850 pairs well with Athlon II X4 640. If either GPU is too strong or too weak, one part holds the other back.
