Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X3D |
|---|---|---|
| Cores | 32 | 12 |
| L3 cache | 64 MB | 128 MB |
| Cinebench R23 (multi) | 52600 | 33500 |
| Boost clock | 4.5 GHz | 5.5 GHz |
Between the M4 Ultra and Ryzen 9 9900X3D, the M4 Ultra comes out ahead in cores / cinebench r23 (multi), while the Ryzen 9 9900X3D wins on l3 cache / boost clock. Overall, the M4 Ultra scores 63.1 and the Ryzen 9 9900X3D scores 58.1 on our Mars Score.
Which should you buy?
The M4 Ultra edges ahead on the Mars Score (63.1 vs 58.1), but the 5.0-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). The single most decisive one: Cores — 166.67% more. 32 vs 12.
Pick the Ryzen 9 9900X3D if you care most about l3 cache / boost clock. Its strongest claims are l3 cache, boost clock. The single most decisive one: L3 cache — 100.00% more. 128 MB vs 64 MB.
Both ship with comparable tdp, so those specs do not 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.
Which should you buy: Apple - M4 Ultra or AMD - Ryzen 9 9900X3D?
Apple - M4 Ultra leads the current Mars Score by 5.0 points.The more useful decision is the trade-off behind that result: compare cores, boost clock against the way you will actually use the product.
Choose Apple - M4 Ultra if…
Apple - M4 Ultra has the measurable edge on core count, cinebench r23 multi.
Choose AMD - Ryzen 9 9900X3D if…
AMD - Ryzen 9 9900X3D has the measurable edge on cache l3 mb, boost clock ghz.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Apple - M4 Ultra wins
- ▲Cores — 166.67% more. 32 vs 12.
- ▲Cinebench R23 (multi) — 57.01% more. 52600 vs 33500.
Why AMD - Ryzen 9 9900X3D wins
- ▲L3 cache — 100.00% more. 128 MB vs 64 MB.
- ▲Boost clock — 22.22% more. 5.5 GHz vs 4.5 GHz.
Spec comparison
Cores
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X3D |
|---|---|---|
| Coresⓘ | 32lead | 12 |
| Threadsⓘ | 32lead | 24 |
| Base clockⓘ | 0 GHz | 4.4 GHzlead |
| Boost clockⓘ | 4.5 GHz | 5.5 GHzlead |
| L3 cacheⓘ | 64 MB | 128 MBlead |
Platform
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X3D |
|---|---|---|
| Socketⓘ | Soldered | AM5 |
| TDPⓘ | 120 W | 120 W |
| Integrated graphicsⓘ | true | true |
| DDR5ⓘ | true | true |
Benchmarks
| Spec | Apple - M4 Ultra | AMD - Ryzen 9 9900X3D |
|---|---|---|
| Cinebench R23 (multi)ⓘ | 52600lead | 33500 |
| Cinebench R23 (single)ⓘ | 2290lead | 2240 |