Performance comparison: which is faster?
AMD Phenom II X4 955 (AMD, 2010) and AMD Athlon II X4 645 (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: Phenom II X4 955 is about 14.3% 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 | Phenom II X4 955 | Athlon II X4 645 |
|---|---|---|
| Performance Score | 4,000 | 3,500 |
| Generation | Phenom II | Athlon II |
| Socket | AM3 | AM3 |
| Release Year | 2010 | 2010 |
| Type | Desktop | Desktop |
| Compatible GPU Example | GeForce GTX 1050 | GeForce GTX 480 |
| If You Want To... | Recommended |
|---|---|
| Prioritize maximum speed for heavy work or a high-end GPU | Phenom II X4 955 |
| Upgrade while reusing the current motherboard | Either works (same AM3 socket) |
| Prioritize value and adequate performance | Athlon II X4 645 (the lower model is often sufficient) |
Phenom II X4 955 is about 14.3% higher by score (Phenom II X4 955: 4000 points / Athlon II X4 645: 3500 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.
Phenom II X4 955 is Phenom II, while Athlon II X4 645 is Athlon II.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 1050 pairs well with Phenom II X4 955 and GeForce GTX 480 pairs well with Athlon II X4 645. If either GPU is too strong or too weak, one part holds the other back.
