# Architecture comparison matrix

Checked 2026-09-16. This is a source-scoped architecture comparison, not a benchmark. Cells summarize the specific documentation linked below; they are not exhaustive statements about every version, backend or configuration. UNKNOWN means the consulted source does not settle the property, not that the project lacks it. Mutable upstream documentation may change.

| Dimension | Horizon immutable cache [H] | Eliseev / Mazur [E] | MoE-Infinity [M] | KTransformers [K] | llama.cpp placement [L] |
| --- | --- | --- | --- | --- | --- |
| Expert source representation | INT4 qpacked, FP16 scales | HQQ mixed low-bit experts | Format-dependent; INT4 and FP4 paths documented | CPU INT4/INT8; other formats supported | GGUF; format depends on model |
| GPU cached representation | Qpacked copies | Quantized expert storage | Path-dependent; compact expert paths documented | GPU GPTQ supported; placement-dependent | Backend/format-dependent; dynamic cache UNKNOWN |
| Expert execution | GPU W4A16, recorded executor | GPU, HQQ-based path | GPU kernels; Marlin INT4 and FP4 paths listed | CPU/GPU hybrid expert computation | Configured CPU/GPU backend |
| Persistent full expansion | No expanded expert cache in this contract | UNKNOWN | UNKNOWN across all paths | UNKNOWN across all paths | UNKNOWN across all backends |
| Source authority | Complete immutable process RAM | Host expert backing; immutable-copy contract UNKNOWN | Host/SSD backing; immutable-copy contract UNKNOWN | Heterogeneous placement; immutable-copy contract UNKNOWN | Model loading/mapping; immutable-copy contract UNKNOWN |
| Eviction writeback | Discard copy; no expert D2H writeback | UNKNOWN | UNKNOWN | UNKNOWN | Dynamic expert eviction contract UNKNOWN |
| Partial/full relationship | Shared design; measured executors differ | Cache budget is configurable | Activation-aware GPU cache | Hot/cold CPU-GPU placement | GPU layer count and tensor placement controls |
| Publication/staging semantics | Bounded staging; completion before atomic generation publication | Per-layer LRU and speculative next-layer loading; atomic generation UNKNOWN | Tracing and prefetching; atomic generation UNKNOWN | Scheduling depends on selected path; atomic generation UNKNOWN | Dynamic publication contract UNKNOWN |

## Sources and scope

- [H: Horizon technical source map](/evidence/releases/technical-preview-residency39-v3/horizon-technical-notes.md): immutable-cache contract, its original P0 scope and campaign executor boundaries. [Current architecture explanation](/architecture.md).
- [E: Eliseev and Mazur, paper v1, sections 3-4](https://arxiv.org/html/2312.17238v1): Mixtral expert offloading, LRU, speculative loading and mixed quantization. [Author implementation](https://github.com/dvmazur/mixtral-offloading). This paper is an especially close architectural precedent, not a matched Horizon baseline.
- [M: MoE-Infinity README](https://github.com/EfficientMoE/MoE-Infinity/blob/main/README.md): host/SSD offload, activation-aware caching, prefetching and compact execution paths. The README explicitly distinguishes the released HuggingFace-oriented implementation from the paper version. This table describes the consulted implementation documentation.
- [K: KTransformers README, inference capabilities](https://github.com/kvcache-ai/ktransformers/blob/main/README.md): heterogeneous expert placement, CPU AMX/AVX computation, CPU quantization and GPU GPTQ. CPU computation is part of this documented path; Horizon's documented host role is authority and transfer coordination.
- [L: llama.cpp server options](https://github.com/ggml-org/llama.cpp/blob/master/tools/server/README.md): `--cpu-moe`, `--n-cpu-moe`, `--gpu-layers` and tensor overrides. These placement controls alone do not specify a dynamic expert cache. No unnamed fork or proposed cache is attributed to upstream llama.cpp here.

## Reading the comparison

Caching, quantization and offloading overlap across these projects. Horizon's explicit ownership, representation and publication rules are useful comparison coordinates; an unresolved cell cannot establish novelty. Matching those contracts requires inspecting a specific implementation path. Comparing performance additionally requires the same model revision, hardware, workload, precision, output policy and timing boundary. No such cross-runtime experiment is included in the published Horizon population.

[Technical brief](/technical-brief.md) · [Recorded experiments](/evidence.md)