Ramulator 2.1 puts a Python interface over DRAM simulation. Timing specifications written in Python generate the C++ simulation code automatically; every simulator component gets a Python proxy for direct scripting. Memory architects can now describe, diff, review, and parameterize a full DRAM model without writing C++. HBM3/4, LPDDR5/6, and GDDR7 are supported in the same release. Open-source.
Ramulator 2.0 required C++ to extend or modify. Changing a DRAM timing model was an engineering-days project, which made design space exploration a batch job: run a fixed set of configurations offline, collect results, make decisions. The Python-first interface in 2.1 inverts that. A timing parameter, a scheduling policy, a bank organization variant: each is now a Python object, scriptable, testable, and diffable. The two-way code generation framework handles the C++ underneath. The validation infrastructure adds formal coverage of DRAM timing constraints and memory controller scheduling behavior, so model changes come with a correctness test, not just a performance trace. A DRAM command trace visualizer ships in the same release.
Memory subsystem validation in CI becomes practical. Parameterized DRAM model variants can be tested automatically, timing violations can be caught before they reach RTL, and latency-throughput curves can be compared against a baseline in a standard pipeline run. When Ramulator required C++ expertise to extend and generated no automated test coverage, none of that was realistic. Teams designing HBM4 controllers for AI accelerators or LPDDR6 controllers for edge SoCs now have an open-source simulator that covers the relevant emerging standards and can be driven from a Python test suite. Vendors selling opaque, proprietary DRAM simulation libraries to those same customers have one fewer argument for the closed-source option.