diff --git a/CMakeLists.txt b/CMakeLists.txt
index 14e3b619..39a3699e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -88,6 +88,10 @@ termforge_warnings(selection_test)
 add_executable(resize_repaint_witness EXCLUDE_FROM_ALL experiments/core/resize_repaint_witness.cpp)
 target_link_libraries(resize_repaint_witness PRIVATE termforge_core)
 termforge_warnings(resize_repaint_witness)
+add_executable(history_memory_probe EXCLUDE_FROM_ALL experiments/core/history_memory_probe.cpp)
+target_link_libraries(history_memory_probe PRIVATE termforge_core)
+target_compile_definitions(history_memory_probe PRIVATE NOMINMAX WIN32_LEAN_AND_MEAN)
+termforge_warnings(history_memory_probe)
 
 add_executable(search_test experiments/core/search_test.cpp)
 target_link_libraries(search_test PRIVATE termforge_core)
diff --git a/docs/EVIDENCE.md b/docs/EVIDENCE.md
index 45dae3a7..7872a3fd 100644
--- a/docs/EVIDENCE.md
+++ b/docs/EVIDENCE.md
@@ -68,6 +68,7 @@ R1 固定总出口的源码为 `ce9b24d`，早期 `2dc8d6d` / `9b16acc` 仍分
 | 范围 | 结果与复现入口 | 可以支持的结论与限制 |
 |---|---|---|
 | 行存储封存与结构单一发布（#169 第二片） | [固定结果](../experiments/core/results/2026-10-29-sealed-row-storage/README.md)、[验证身份](../experiments/core/results/2026-10-29-sealed-row-storage/validation.json) | `Screen::lines/history` 私有，只读口 + 23 文件/363 处迁移；Find overlay 改文档 rank；默认 Release 构建 exit 0、核心 8/8、扩展快测 20/20、candidate 源 /W4 编译 0。无新 VT/重排行为；运行中跨重排 Search、Qt 与候选运行由宿主作业复核。 |
+| 保留历史的内存与单次 Search 成本（#164 剩余项） | [固定结果](../experiments/core/results/2026-10-29-history-memory/README.md)、[验证身份](../experiments/core/results/2026-10-29-history-memory/validation.json) | 生产 `Screen`/`TextSearch` 在 H=100/1000/10000、各 3 个新进程样本：每行私有增量收敛 ~5.8–6.9 KB，H=10000 私有提交 ~59 MB；整文档 Search ~54 ms/199 步。不是 r164 fork 对照，也不是性能预算；不关闭 #164。 |
 | 结构重排下的增量 Search（#169 延期项 / #27 前置） | [固定结果](../experiments/core/results/2026-10-29-search-reorder/README.md)、[验证身份](../experiments/core/results/2026-10-29-search-reorder/validation.json) | `TextSearch` 以文档 rank 维护扫描前缀：order revision 检测、局部 `repair_order`、rank 化 `rewind`/`match`/`prune`。新 `search_reorder_core` 覆盖扫描中重排、重排后导航、淘汰与有序回归；核心 10/10。无 UI/Find 集成、无重排成本测量，不声明 #27/R2 通过。 |
 | 默认核心缩小与重绘交错（#156） | [固定四-case机制诊断](../experiments/shell/results/2026-10-29-resize-repaint-witness/README.md)、[脱敏验证](../experiments/shell/results/2026-10-29-resize-repaint-witness/validation.json) | A/C保留2499B，B/D在第五段重绘首次失效且行分配路径不同；只见证机制，原CI切点/根因未知，未修生产。witness结束后Job仍active1，发起一次终止后归零；成员身份/逐句柄退出未知，不称全树自然退出。 |
 | 系统 ConPTY resize 后的客户端尺寸回复（#145 未关闭） | [有界重复采样](../experiments/conpty/results/2026-10-29-resize-reply-r145/README.md)、[固定验证身份](../experiments/conpty/results/2026-10-29-resize-reply-r145/validation.json) | 新增 tag 化探针：hosted 2000 次交替 resize + 500 次全新会话、本机 200 + 100，均无陈旧回复，buffer/window 无分歧，resize VT 全部先于回复，回复中位 8.7–16.1ms。只否定“resize 后立即查询存在必然竞态”；原两条 CI 失败、原始探针/5 秒等待与 #145/#38 状态不变。 |
diff --git a/experiments/core/history_memory_probe.cpp b/experiments/core/history_memory_probe.cpp
new file mode 100644
index 00000000..d45cca90
--- /dev/null
+++ b/experiments/core/history_memory_probe.cpp
@@ -0,0 +1,99 @@
+// Diagnostic only (issue #164 remainder): retained-history memory and a single
+// bounded Search at fixed history sizes on the production Screen/TextSearch.
+// It reports what it measured and asserts nothing about performance targets.
+#include "screen.hpp"
+#include "terminal.hpp"
+#include "text_document.hpp"
+#include "text_search.hpp"
+#include <windows.h>
+#include <psapi.h>
+#include <chrono>
+#include <cstdint>
+#include <iostream>
+#include <string>
+
+using namespace termforge;
+
+namespace {
+struct Usage { SIZE_T working = 0, peak_working = 0, private_bytes = 0; };
+
+Usage current_usage() {
+    using Fn = BOOL(WINAPI*)(HANDLE, PROCESS_MEMORY_COUNTERS_EX*, DWORD);
+    static const auto fn = reinterpret_cast<Fn>(
+        GetProcAddress(GetModuleHandleW(L"kernel32.dll"), "K32GetProcessMemoryInfo"));
+    PROCESS_MEMORY_COUNTERS_EX counters{};
+    counters.cb = sizeof(counters);
+    if (!fn || !fn(GetCurrentProcess(), &counters, sizeof(counters))) return {};
+    return {counters.WorkingSetSize, counters.PeakWorkingSetSize, counters.PrivateUsage};
+}
+long long micros(std::chrono::steady_clock::time_point from, std::chrono::steady_clock::time_point to) {
+    return std::chrono::duration_cast<std::chrono::microseconds>(to - from).count();
+}
+} // namespace
+
+int main(int argc, char** argv) {
+    size_t history = 0, lines = 0;
+    std::string query = "needle";
+    for (int index = 1; index < argc; ++index) {
+        const std::string arg = argv[index];
+        if (arg == "--history" && index + 1 < argc) history = static_cast<size_t>(std::stoul(argv[++index]));
+        else if (arg == "--lines" && index + 1 < argc) lines = static_cast<size_t>(std::stoul(argv[++index]));
+        else if (arg == "--query" && index + 1 < argc) query = argv[++index];
+        else { std::cerr << "usage: history_memory_probe --history N --lines M [--query text]\n"; return 2; }
+    }
+    if (!history || history > 10000 || !lines) { std::cerr << "history 1..10000 and lines>0 required\n"; return 2; }
+
+    const Usage before = current_usage();
+    Parser parser(24, 80, history);
+    // Fill the retained history: the live screen keeps 24 rows, the rest evict
+    // into the bounded history in document order.
+    const auto fill_begin = std::chrono::steady_clock::now();
+    std::string batch;
+    batch.reserve(1 << 20);
+    for (size_t line = 0; line < lines; ++line) {
+        char prefix[16];
+        std::snprintf(prefix, sizeof(prefix), "R%06zu ", line);
+        std::string text = prefix;
+        // One hit every 1000 rows, otherwise harmless filler.
+        if (line % 1000 == 0) text += query;
+        else text += "payload-";
+        while (text.size() < 78) text += static_cast<char>('a' + (line % 26));
+        text += "\r\n";
+        batch += text;
+    }
+    parser.feed(batch);
+    const auto fill_end = std::chrono::steady_clock::now();
+    Sleep(150); // Let the allocator settle before the snapshot is taken.
+    const Usage after_fill = current_usage();
+
+    const TextDocument document(parser.screen);
+    TextSearch search;
+    const auto search_begin = std::chrono::steady_clock::now();
+    const auto generation = search.start(document, query);
+    size_t steps = 0, work = 0;
+    while (search.status() == SearchStatus::running && steps < 1000000) {
+        const auto progress = search.step(document, generation, 4096);
+        work += progress.work_used;
+        ++steps;
+    }
+    const auto search_end = std::chrono::steady_clock::now();
+
+    std::cout << "{\"history_limit\":" << history
+              << ",\"lines_fed\":" << lines
+              << ",\"retained\":" << document.size()
+              << ",\"history_rows\":" << parser.screen.history_size()
+              << ",\"query\":\"" << query << "\""
+              << ",\"search_status\":" << static_cast<int>(search.status())
+              << ",\"search_matches\":" << search.matches().size()
+              << ",\"search_steps\":" << steps
+              << ",\"search_work\":" << work
+              << ",\"fill_us\":" << micros(fill_begin, fill_end)
+              << ",\"search_us\":" << micros(search_begin, search_end)
+              << ",\"working_before\":" << before.working
+              << ",\"working_after\":" << after_fill.working
+              << ",\"private_before\":" << before.private_bytes
+              << ",\"private_after\":" << after_fill.private_bytes
+              << ",\"peak_working\":" << after_fill.peak_working
+              << "}" << std::endl;
+    return 0;
+}
diff --git a/experiments/core/results/2026-10-29-history-memory/README.md b/experiments/core/results/2026-10-29-history-memory/README.md
new file mode 100644
index 00000000..bab8369f
--- /dev/null
+++ b/experiments/core/results/2026-10-29-history-memory/README.md
@@ -0,0 +1,32 @@
+# 保留历史的内存与单次 Search 成本（#164 剩余项）
+
+#164 的最后一项要求"在相同正确性下记录定位/重建次数、内存与首访/搜索成本"覆盖 100/1000/10000 行。定位/重建已由 [line-order 成本](https://github.com/JavaZeroo/termforge/blob/main/experiments/core/results/2026-10-29-line-order-r164/README.md) 提供；本片补**生产 `Screen` 的历史内存**与**生产 `TextSearch` 在 H=10000 的整文档扫描成本**。
+
+## 方法
+
+新增 `history_memory_probe`（`EXCLUDE_FROM_ALL`，默认不构建、不注册 CTest）：
+
+- 每个样本一个**新进程**，`Parser(24, 80, N)`，喂入 `N+40` 行（行宽 78 字节 + CRLF），每 1000 行含一次 `needle`；
+- 用 `K32GetProcessMemoryInfo` 读工作集/私有提交/峰值，读点在填充前后各一次（中间 150ms 让分配器稳定）；
+- 用 `steady_clock` 记录填充与整文档 Search 的耗时、步数、work 单位与命中数；
+- 每个 H 跑 3 个样本，原始 JSON 见 [validation.json](validation.json)。
+
+## 结果（Windows 11 10.0.26200，Release，3 样本）
+
+| H | 保留行 | 命中 | Search 步数 | Search work | 填充 µs | Search µs | 私有提交 前→后 | 工作集 前→后 | 每行私有增量 |
+|---|---|---|---|---|---|---|---|---|---|
+| 100 | 124 | 0（第 0 行已淘汰） | 3 | 9,965 | 590–752 | 867–1,200 | 0.69→2.54 MB | 4.35→5.17 MB | ~14.5 KB |
+| 1000 | 1024 | 1 | 21 | 82,865 | 5,120–7,839 | 5,916–6,023 | 0.67→7.69 MB | 4.34→10.33 MB | ~6.9 KB |
+| 10000 | 10024 | 10 | 199 | 811,865 | 53,969–65,463 | 53,389–58,331 | 0.68→58.97 MB | 4.35→61.15 MB | ~5.8 KB |
+
+- 每行私有增量随 H 增大收敛到 **~5.8–6.9 KB**（H=100 含固定分配，故偏高）；H=10000 时私有提交约 **59 MB**、工作集约 **61 MB**。
+- 整文档 Search 在 H=10000 为 **~54 ms**（199 步 × 4096 work），线性于行数；H=1000 为 ~6 ms。
+- 命中数符合预期：H=100 时第 0 行已淘汰、下一个命中在 1000 行且不在保留窗口内，故 0 命中；H=1000 保留 1 个；H=10000 保留 10 个。
+
+## 解释与边界
+
+- 这是**生产** `Screen`/`TextSearch` 的观测，不是 r164 fork 的 Scan/LazyTable 对照；两者不可直接比较。
+- 每行成本主要来自 `Cell` 的 `std::string text` 与完整属性结构（80 列 × 约 72 B），本轮未尝试压缩或共享存储；该数值是后续历史压缩/大历史实验的基线输入，**不是性能预算**。
+- 峰值工作集等于最终工作集（没有额外瞬时峰值），但进程基线含运行时与二进制映像；每行数字取自前后差值。
+- 未覆盖：淘汰/重排混合、分块填充、真实 ConPTY 输出、UI 呈现、长期增长；Search 只测一条查询与一个命中分布。
+- 本片不关闭 #164：H=10000 的静态对照配方（r164 fork）与 RSS 之外的项目仍按原记录分别成立。
diff --git a/experiments/core/results/2026-10-29-history-memory/validation.json b/experiments/core/results/2026-10-29-history-memory/validation.json
new file mode 100644
index 00000000..56f5e67e
--- /dev/null
+++ b/experiments/core/results/2026-10-29-history-memory/validation.json
@@ -0,0 +1,143 @@
+{
+  "schema": "termforge-core-history-memory-v1",
+  "issue": 164,
+  "base_commit": "02c42e90114b535a9b5b88c566b504767fff8a61",
+  "configuration": {
+    "platform": "Windows-11-10.0.26200",
+    "generator": "Visual Studio 17 2022",
+    "build_type": "Release",
+    "binary": "history_memory_probe (EXCLUDE_FROM_ALL)"
+  },
+  "method": {
+    "parser": "Parser(24, 80, N)",
+    "line_bytes": 80,
+    "hit_pattern": "one needle every 1000 rows",
+    "samples_per_size": 3,
+    "process": "fresh process per sample",
+    "memory_api": "K32GetProcessMemoryInfo"
+  },
+  "samples": [
+    {
+      "history": 100,
+      "retained": 124,
+      "matches": 0,
+      "steps": 3,
+      "work": 9965,
+      "fill_us": [
+        590,
+        581,
+        752
+      ],
+      "search_us": [
+        987,
+        867,
+        1200
+      ],
+      "private_before": [
+        741376,
+        684032,
+        688128
+      ],
+      "private_after": [
+        2539520,
+        2568192,
+        2572288
+      ],
+      "working_before": [
+        4837376,
+        4349952,
+        4354048
+      ],
+      "working_after": [
+        5652480,
+        5169152,
+        5173248
+      ]
+    },
+    {
+      "history": 1000,
+      "retained": 1024,
+      "matches": 1,
+      "steps": 21,
+      "work": 82865,
+      "fill_us": [
+        5719,
+        5120,
+        7839
+      ],
+      "search_us": [
+        6023,
+        6006,
+        5916
+      ],
+      "private_before": [
+        671744,
+        684032,
+        684032
+      ],
+      "private_after": [
+        7688192,
+        7692288,
+        7692288
+      ],
+      "working_before": [
+        4337664,
+        4345856,
+        4349952
+      ],
+      "working_after": [
+        10330112,
+        10338304,
+        10395648
+      ]
+    },
+    {
+      "history": 10000,
+      "retained": 10024,
+      "matches": 10,
+      "steps": 199,
+      "work": 811865,
+      "fill_us": [
+        65463,
+        53969,
+        55176
+      ],
+      "search_us": [
+        58331,
+        53796,
+        53389
+      ],
+      "private_before": [
+        675840,
+        679936,
+        679936
+      ],
+      "private_after": [
+        58966016,
+        58830848,
+        58970112
+      ],
+      "working_before": [
+        4341760,
+        4345856,
+        4345856
+      ],
+      "working_after": [
+        61145088,
+        61120512,
+        61198336
+      ]
+    }
+  ],
+  "source_sha256": {
+    "experiments/core/history_memory_probe.cpp": "787b4eaa7f8b13b27cc2429cf9f79412d60315fcb1ed3993388866b40e0ffba5",
+    "CMakeLists.txt": "ada254edee850f8570973ffa499ea64532507bf2a510e109e079a7231f45dc6b"
+  },
+  "limitations": [
+    "生产 Screen/TextSearch，不是 r164 fork 的 Scan/LazyTable 对照",
+    "未覆盖淘汰/重排混合、真实 ConPTY、UI 与长期增长",
+    "单查询单命中分布；不是性能预算或容差",
+    "进程基线含运行时与二进制映像"
+  ],
+  "performance_claim": false
+}