Ryzen 9 7900X vs Ryzen 9 9900X
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, Ryzen 9 7900X and Ryzen 9 9900X 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.