diff --git a/src/bin/benchpress_bin.ml b/src/bin/benchpress_bin.ml
index 5c36aef..436c997 100644
--- a/src/bin/benchpress_bin.ml
+++ b/src/bin/benchpress_bin.ml
@@ -21,9 +21,12 @@ module Run = struct
     let open Cmdliner in
     let aux j cpus pp_results dyn paths dir_files proof_dir defs task timeout
         memory meta provers csv summary no_color output save wal_mode
-        desktop_notification no_failure update =
+        desktop_notification no_failure update ramdisk =
       catch_err @@ fun () ->
       if no_color then CCFormat.set_color_default false;
+      (match ramdisk with
+      | Some ramdisk -> Misc.set_ramdisk ramdisk
+      | None -> ());
       let dyn =
         if dyn then
           Some true
@@ -160,13 +163,20 @@ module Run = struct
             ~doc:
               "if the output file already exists, overwrite it with the new \
                one.")
+    and ramdisk =
+      let doc =
+        "Path to the directory to use as temporary storage for prover input \
+         and output."
+      in
+      Arg.(value & opt (some string) None & info [ "ramdisk" ] ~doc)
     in
+
     Cmd.v (Cmd.info ~doc "run")
       Term.(
         const aux $ j $ cpus $ pp_results $ dyn $ paths $ dir_files $ proof_dir
         $ defs $ task $ timeout $ memory $ meta $ provers $ csv $ summary
         $ no_color $ output $ save $ wal_mode $ desktop_notification
-        $ no_failure $ update)
+        $ no_failure $ update $ ramdisk)
 end
 
 module Slurm = struct
diff --git a/src/core/Misc.ml b/src/core/Misc.ml
index eb174f6..5b817be 100644
--- a/src/core/Misc.ml
+++ b/src/core/Misc.ml
@@ -478,6 +478,39 @@ let establish_server n server_fun sockaddr =
   let sock, _ = mk_socket sockaddr in
   start_server n server_fun sock
 
+(* Not actually a ramdisk on windows *)
+let ramdisk_ref =
+  ref
+    (if Sys.unix then
+      Some "/dev/shm"
+    else
+      None)
+
+let has_ramdisk () = Option.is_some !ramdisk_ref
+
+let get_ramdisk () =
+  match !ramdisk_ref with
+  | Some ramdisk -> ramdisk
+  | None -> Filename.get_temp_dir_name ()
+
+let set_ramdisk ramdisk = ramdisk_ref := Some ramdisk
+
+(* Turns out that [Filename.open_temp_file] is not thread-safe *)
+let open_temp_file = CCLock.create Filename.open_temp_file
+
+let open_ram_file prefix suffix =
+  let temp_dir = get_ramdisk () in
+  CCLock.with_lock open_temp_file @@ fun open_temp_file ->
+  open_temp_file ~temp_dir prefix suffix
+
+let with_ram_file prefix suffix f =
+  let fname, oc = open_ram_file prefix suffix in
+  Fun.protect
+    ~finally:(fun () ->
+      close_out oc;
+      try Sys.remove fname with Sys_error _ -> ())
+    (fun () -> f fname)
+
 let with_affinity cpu f =
   let aff = Processor.Affinity.get_ids () in
   Processor.Affinity.set_ids [ cpu ];
diff --git a/src/core/Run_proc.ml b/src/core/Run_proc.ml
index f0145fc..5b390f6 100644
--- a/src/core/Run_proc.ml
+++ b/src/core/Run_proc.ml
@@ -3,41 +3,67 @@ module Log = (val Logs.src_log (Logs.Src.create "run-proc"))
 let int_of_process_status = function
   | Unix.WEXITED i | Unix.WSIGNALED i | Unix.WSTOPPED i -> i
 
+(* There is no version of [create_process] that opens a shell, so we roll our
+   own version of [open_process] . *)
+let sh cmd =
+  if Sys.unix || Sys.cygwin then
+    Unix.create_process "/bin/sh" [| "/bin/sh"; "-c"; cmd |]
+  else if Sys.win32 then (
+    let shell =
+      try Sys.getenv "COMSPEC"
+      with Not_found -> raise Unix.(Unix_error (ENOEXEC, "sh", cmd))
+    in
+    Unix.create_process shell [| shell; "/c"; cmd |]
+  ) else
+    Format.kasprintf failwith "Unsupported OS type: %s" Sys.os_type
+
+(* Available as [Filename.null] on OCaml >= 4.10 *)
+let null () =
+  if Sys.unix || Sys.cygwin then
+    "/dev/null"
+  else if Sys.win32 then
+    "NUL"
+  else
+    (* Nobody is running benchpress with js_of_ocaml… right? *)
+    Format.kasprintf failwith "Unsupported OS type: %s" Sys.os_type
+
 let run cmd : Run_proc_result.t =
-  let start = Ptime_clock.now () in
-  (* call process and block *)
-  let p =
-    try
-      let oc, ic, errc = Unix.open_process_full cmd (Unix.environment ()) in
-      close_out ic;
-      (* read out and err *)
-      let err = ref "" in
-      let t_err = Thread.create (fun e -> err := CCIO.read_all e) errc in
-      let out = CCIO.read_all oc in
-      Thread.join t_err;
-      let status = Unix.close_process_full (oc, ic, errc) in
-      object
-        method stdout = out
-        method stderr = !err
-        method errcode = int_of_process_status status
-        method status = status
-      end
-    with e ->
-      object
-        method stdout = ""
-        method stderr = "process died: " ^ Printexc.to_string e
-        method errcode = 1
-        method status = Unix.WEXITED 1
-      end
-  in
-  let errcode = p#errcode in
-  Log.debug (fun k ->
-      k "(@[run.done@ :errcode %d@ :cmd %a@]" errcode Misc.Pp.pp_str cmd);
-  (* Compute time used by the command *)
-  let rtime = Ptime.diff (Ptime_clock.now ()) start |> Ptime.Span.to_float_s in
-  let utime = 0. in
-  let stime = 0. in
-  let stdout = p#stdout in
-  let stderr = p#stderr in
-  Log.debug (fun k -> k "stdout:\n%s\nstderr:\n%s" stdout stderr);
-  { Run_proc_result.stdout; stderr; errcode; rtime; utime; stime }
+  (* create temporary files for stdout and stderr *)
+  try
+    Misc.with_ram_file "stdout" "" @@ fun stdout_f ->
+    Misc.with_ram_file "stderr" "" @@ fun stderr_f ->
+    let stdout_fd = Unix.openfile stdout_f [ O_WRONLY; O_KEEPEXEC ] 0o640 in
+    let stderr_fd = Unix.openfile stderr_f [ O_WRONLY; O_KEEPEXEC ] 0o640 in
+    let stdin_fd = Unix.openfile (null ()) [ O_RDONLY; O_KEEPEXEC ] 0o000 in
+    (* call process and block *)
+    let errcode, rtime =
+      let start = Ptime_clock.now () in
+      let pid = sh cmd stdin_fd stdout_fd stderr_fd in
+      let _, status = Unix.waitpid [] pid in
+      (* Compute time used by the command *)
+      let rtime =
+        Ptime.diff (Ptime_clock.now ()) start |> Ptime.Span.to_float_s
+      in
+      int_of_process_status status, rtime
+    in
+    let stdout = CCIO.with_in stdout_f @@ CCIO.read_all in
+    let stderr = CCIO.with_in stderr_f @@ CCIO.read_all in
+    Unix.close stdout_fd;
+    Unix.close stderr_fd;
+    Unix.close stdin_fd;
+    Log.debug (fun k ->
+        k "(@[run.done@ :errcode %d@ :cmd %a@ :stdout %s@ :stdout_f %s@]"
+          errcode Misc.Pp.pp_str cmd stdout stdout_f);
+    let utime = 0. in
+    let stime = 0. in
+    Log.debug (fun k -> k "stdout:\n%s\nstderr:\n%s" stdout stderr);
+    { Run_proc_result.stdout; stderr; errcode; rtime; utime; stime }
+  with e ->
+    {
+      stdout = "";
+      stderr = "benchpress error: " ^ Printexc.to_string e;
+      errcode = 1;
+      rtime = 0.;
+      utime = 0.;
+      stime = 0.;
+    }