M4 Ultra vs Ryzen AI 9 HX 395+
A side-by-side readout for l3 cache.
Understanding l3 cache
CPU cache sits between the cores and main memory (DRAM), buffering data the cores will likely need next.
Hierarchy
- L1 — 32–64 KB per core, ~1 ns access.
- L2 — 512 KB–2 MB per core, ~3 ns.
- L3 — 8–192 MB shared, ~12 ns.
- DRAM — gigabytes, ~80 ns.
Why it matters
A workload that fits in L3 runs 5–10× faster than one that spills to DRAM. AMD's X3D parts (Ryzen 7800X3D, 9800X3D, 9950X3D) stack 64–96 MB of extra cache — the gaming-best CPUs of their generation, frequently 15–25% faster than non-X3D siblings in CPU-bound titles.
Cache vs clock
For gaming, cache often beats raw clock speed. For sustained multithreaded workloads, clocks and core count win.
This matchupIn this spec, M4 Ultra and Ryzen AI 9 HX 395+ are effectively tied at 64MB — buyers can treat them as equivalent on l3 cache alone.
What is cache?
Small, fast memory inside a CPU that stores recently-used data and instructions. L1 is fastest and smallest; L3 is largest and shared across cores. Cache size meaningfully impacts gaming and database workloads.
Read the full Cache explainer →Other specs on this comparison
See the full CPUs category for all products ranked by Mars Score.