diff --git a/AUTHORS.txt b/AUTHORS.txt
index 5b2cdd084..33ca79a1c 100644
--- a/AUTHORS.txt
+++ b/AUTHORS.txt
@@ -44,6 +44,8 @@ Dr Ian Bush [consultant]
     HPC
 
 External contributors:
+Mai Đức Khang
+    implemented RAM probe (for unitaryHACK issue #600)
 James Richings
     patched overflow in bitwise.hpp logic
 Luc Jaulmes
diff --git a/README.md b/README.md
index 260d4b8bb..9e05597a2 100644
--- a/README.md
+++ b/README.md
@@ -257,6 +257,7 @@ See the [docs](docs/README.md) for enabling acceleration and running the unit te
 
 In addition to QuEST's [authors](AUTHORS.txt), we sincerely thank the following external contributors to QuEST.
 
+- [Mai Đức Khang](https://github.com/Roll249) for implementing a RAM probe (unitaryHACK 2025 [#600](https://github.com/QuEST-Kit/QuEST/issues/600)). 
 - [James Richings](https://github.com/JPRichings) for patching a v4 overflow bug.
 - [Luc Jaulmes](https://github.com/lucjaulmes) for patching v4's CMake installation.
 - [Jakub Adamski](https://github.com/jjacobx) for optimising distributed communication of max-size messages.
diff --git a/quest/src/core/memory.cpp b/quest/src/core/memory.cpp
index 36eedb596..fc2a4c39c 100644
--- a/quest/src/core/memory.cpp
+++ b/quest/src/core/memory.cpp
@@ -21,6 +21,17 @@
 
 #include <cstdlib>
 
+// Platform-specific includes for RAM querying
+#if defined(__linux__)
+    #include <sys/sysinfo.h>
+#elif defined(__APPLE__)
+    #include <sys/types.h>
+    #include <sys/sysctl.h>
+#elif defined(_WIN32)
+    #define NOMINMAX
+    #include <windows.h>
+#endif
+
 
 
 /*
@@ -196,11 +207,23 @@ qindex mem_getMaxNumKrausMapMatricesBeforeLocalMemSizeofOverflow(int numQubits)
 
 
 qindex mem_tryGetLocalRamCapacityInBytes() {
-
-    /// @todo attempt to find total Ram
-
-    // if we're unable to find total RAM, throw an exception
-    // (which the caller should catch and gracefully continue)
+    #if defined(__linux__)
+        struct sysinfo info;
+        if (sysinfo(&info) == 0)
+            return (qindex) info.totalram * info.mem_unit;
+    #elif defined(__APPLE__)
+        int mib[2] = {CTL_HW, HW_MEMSIZE};
+        int64_t memsize = 0;
+        size_t len = sizeof(memsize);
+        if (sysctl(mib, 2, &memsize, &len, NULL, 0) == 0 && memsize > 0)
+            return (qindex) memsize;
+    #elif defined(_WIN32)
+        MEMORYSTATUSEX statex;
+        statex.dwLength = sizeof(statex);
+        if (GlobalMemoryStatusEx(&statex))
+            return (qindex) statex.ullTotalPhys;
+    #endif
+    // fallback: throw exception
     throw (mem::COULD_NOT_QUERY_RAM) false;
 }
 
diff --git a/tests/unit/channels.cpp b/tests/unit/channels.cpp
index b0a7ab314..e068368c5 100644
--- a/tests/unit/channels.cpp
+++ b/tests/unit/channels.cpp
@@ -126,7 +126,11 @@ TEST_CASE( "createKrausMap", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createKrausMap(12,1), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createKrausMap(12,1), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("exceeds the available memory") ||
+                ContainsSubstring("available GPU memory") );
             #endif
         }
 
@@ -512,7 +516,11 @@ TEST_CASE( "createSuperOp", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createSuperOp(12), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createSuperOp(12), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("exceeds that available") );
             #endif
         }
     }
diff --git a/tests/unit/matrices.cpp b/tests/unit/matrices.cpp
index 591e3bc7b..ef92dbcda 100644
--- a/tests/unit/matrices.cpp
+++ b/tests/unit/matrices.cpp
@@ -456,7 +456,11 @@ TEST_CASE( "createCompMatr", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createCompMatr(25), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createCompMatr(25), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("exceeds the available RAM") );
             #endif
         }
     }
@@ -529,7 +533,11 @@ TEST_CASE( "createDiagMatr", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createDiagMatr(50), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createDiagMatr(50), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("exceeds the available RAM") );
             #endif
         }
     }
@@ -602,7 +610,11 @@ TEST_CASE( "createFullStateDiagMatr", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createFullStateDiagMatr(50), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createFullStateDiagMatr(50), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("exceeds the available RAM") );
             #endif
         }
 
@@ -698,7 +710,11 @@ TEST_CASE( "createCustomFullStateDiagMatr", TEST_CATEGORY ) {
                 // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
                 // advance or whether it proceeded to malloc() which subsequently failed
                 #ifndef SANITIZER_IS_ACTIVE
-                REQUIRE_THROWS_WITH( createCustomFullStateDiagMatr(50, mpi,gpu,omp), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+                REQUIRE_THROWS_WITH( createCustomFullStateDiagMatr(50, mpi,gpu,omp), 
+                    ContainsSubstring("failed") || 
+                    ContainsSubstring("insufficient available memory") || 
+                    ContainsSubstring("available GPU memory") ||
+                    ContainsSubstring("exceeds the available RAM") );
                 #endif
             }
         }
diff --git a/tests/unit/qureg.cpp b/tests/unit/qureg.cpp
index aaf3bb0cd..4b2b46311 100644
--- a/tests/unit/qureg.cpp
+++ b/tests/unit/qureg.cpp
@@ -125,7 +125,11 @@ TEST_CASE( "createQureg", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createQureg(50), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createQureg(50), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("RAM") );
             #endif
         }
     }
@@ -210,7 +214,11 @@ TEST_CASE( "createDensityQureg", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createDensityQureg(25), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createDensityQureg(25), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("RAM") );
             #endif
         }
     }
@@ -302,7 +310,11 @@ TEST_CASE( "createForcedQureg", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createForcedQureg(50), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createForcedQureg(50), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("RAM") );
             #endif
         }
     }
@@ -395,7 +407,11 @@ TEST_CASE( "createForcedDensityQureg", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createForcedDensityQureg(25), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createForcedDensityQureg(25), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("RAM") );
             #endif
         }
     }
@@ -531,8 +547,16 @@ TEST_CASE( "createCustomQureg", TEST_CATEGORY ) {
             // GPU-accel or distributed) and whether memory-probers realised there was insufficient memory in
             // advance or whether it proceeded to malloc() which subsequently failed
             #ifndef SANITIZER_IS_ACTIVE
-            REQUIRE_THROWS_WITH( createCustomQureg(50, 0, 0,0,0), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
-            REQUIRE_THROWS_WITH( createCustomQureg(25, 1, 0,0,0), ContainsSubstring("failed") || ContainsSubstring("insufficient available memory") || ContainsSubstring("available GPU memory") );
+            REQUIRE_THROWS_WITH( createCustomQureg(50, 0, 0,0,0), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("RAM") );
+            REQUIRE_THROWS_WITH( createCustomQureg(25, 1, 0,0,0), 
+                ContainsSubstring("failed") || 
+                ContainsSubstring("insufficient available memory") || 
+                ContainsSubstring("available GPU memory") ||
+                ContainsSubstring("RAM") );
             #endif
         }
     }