Between the M4 Ultra and Ryzen 9 9900X, the M4 Ultra comes out ahead in cores and cinebench r23 (multi), while the Ryzen 9 9900X wins on boost clock. Overall, the M4 Ultra scores 63.1 and the Ryzen 9 9900X scores 56.6 on our Mars Score.
Which should you buy?
The M4 Ultra edges ahead on the Mars Score (63.1 vs 56.6), but the 6.5-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the M4 Ultra if you push the hardware — gaming, on-device AI, heavy multitasking — and the extra compute headroom is worth the trade-offs. The biggest gaps in its favor are cores, cinebench r23 (multi).
Pick the Ryzen 9 9900X if you care most about boost clock. Its strongest claims are boost clock.
Both ship with comparable l3 cache, tdp, so those specs don't separate the two — focus on the differences below.
Bottom line: the M4 Ultra is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Apple - M4 Ultra wins
- ▲Cores — 166.67% more. 32 vs 12.
- ▲Cinebench R23 (multi) — 61.85% more. 52600 vs 32500.
Why AMD - Ryzen 9 9900X wins
- ▲Boost clock — 24.44% more. 5.6 GHz vs 4.5 GHz.
Spec comparison
Cores
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X |
|---|---|---|
| Coresⓘ | 32lead | 12 |
| Threadsⓘ | 32lead | 24 |
| Base clockⓘ | 0 GHz | 4.4 GHzlead |
| Boost clockⓘ | 4.5 GHz | 5.6 GHzlead |
| L3 cacheⓘ | 64 MB | 64 MB |
Platform
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X |
|---|---|---|
| Socketⓘ | Soldered | AM5 |
| TDPⓘ | 120 W | 120 W |
| Integrated graphicsⓘ | true | true |
| DDR5ⓘ | true | true |
Benchmarks
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X |
|---|---|---|
| Cinebench R23 (multi)ⓘ | 52600lead | 32500 |
| Cinebench R23 (single)ⓘ | 2290lead | 2230 |
Frequently asked
Spec-level deep dives
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