diff --git a/client/cs_benchmark.cpp b/client/cs_benchmark.cpp
index cbbc8e3cdf..2f28bee5ed 100644
--- a/client/cs_benchmark.cpp
+++ b/client/cs_benchmark.cpp
@@ -68,6 +68,8 @@
 #include "log_flags.h"
 #include "client_state.h"
 
+#include <vector>
+
 // defaults in case benchmarks fail or time out.
 // better to err on the low side so hosts don't get too much work
 
@@ -119,7 +121,7 @@ struct BENCHMARK_DESC {
 #endif
 };
 
-static BENCHMARK_DESC* benchmark_descs=0;
+static std::vector<BENCHMARK_DESC> benchmark_descs;
 static double cpu_benchmarks_start;
 static int bm_ncpus;
     // user might change ncpus during benchmarks.
@@ -260,20 +262,21 @@ void CLIENT_STATE::start_cpu_benchmarks() {
     remove_benchmark_file(BM_TYPE_INT);
     cpu_benchmarks_start = dtime();
 
-    if (benchmark_descs) {
-        free(benchmark_descs);
+    if (!benchmark_descs.empty()) {
+        benchmark_descs.clear();
     }
     bm_ncpus = ncpus;
-    benchmark_descs = (BENCHMARK_DESC*)calloc(bm_ncpus, sizeof(BENCHMARK_DESC));
     benchmarks_running = true;
 
     for (i=0; i<bm_ncpus; i++) {
+        benchmark_descs.push_back(BENCHMARK_DESC());
+
         benchmark_descs[i].ordinal = i;
         benchmark_descs[i].done = false;
         benchmark_descs[i].error = false;
 #ifdef _WIN32
         benchmark_descs[i].handle = CreateThread(
-            NULL, 0, win_cpu_benchmarks, benchmark_descs+i, 0,
+            NULL, 0, win_cpu_benchmarks, &benchmark_descs, 0,
             &benchmark_descs[i].pid
         );
         int n = host_info.p_ncpus;
@@ -289,7 +292,7 @@ void CLIENT_STATE::start_cpu_benchmarks() {
                 perror("setpriority");
             }
 #endif
-            int retval = cpu_benchmarks(benchmark_descs+i);
+            int retval = cpu_benchmarks(&benchmark_descs);
             fflush(NULL);
             _exit(retval);
         } else {