diff --git a/collects/setup/option-sig.rkt b/collects/setup/option-sig.rkt
index cad8bedaa7..00e9f426bd 100644
--- a/collects/setup/option-sig.rkt
+++ b/collects/setup/option-sig.rkt
@@ -21,7 +21,6 @@
      call-install
      call-post-install
      pause-on-errors
-     parallel-build
      parallel-workers
      force-unpacks
      doc-pdf-dest
diff --git a/collects/setup/option-unit.rkt b/collects/setup/option-unit.rkt
index 3bc83ca76a..6fe9959d04 100644
--- a/collects/setup/option-unit.rkt
+++ b/collects/setup/option-unit.rkt
@@ -27,8 +27,7 @@
 
   (define setup-program-name (make-parameter "setup-plt"))
 
-  (define-flag-param parallel-build #t)
-  (define-flag-param parallel-workers (processor-count))
+  (define-flag-param parallel-workers (min (processor-count) 8))
   (define-flag-param verbose #f)
   (define-flag-param make-verbose #f)
   (define-flag-param compiler-verbose #f)
diff --git a/collects/setup/setup-cmdline.rkt b/collects/setup/setup-cmdline.rkt
index 180ae58b86..b141b66068 100644
--- a/collects/setup/setup-cmdline.rkt
+++ b/collects/setup/setup-cmdline.rkt
@@ -39,10 +39,7 @@
                    (call-install #f)
                    (make-launchers #f)
                    (make-info-domain #f)
-                   (parallel-build #f)
                    (make-docs #f)))]
-     [("-u" "--no-parallel-build") "Do not use parallel build"
-      (add-flags '((parallel-build #f)))]
      [("-j" "--workers") workers "Use <#> parallel-workers"
       (add-flags `((parallel-workers ,(string->number workers))))]
      [("-n" "--no-zo") "Do not produce .zo files"
diff --git a/collects/setup/setup-unit.rkt b/collects/setup/setup-unit.rkt
index 3336ee1f32..bd12555ece 100644
--- a/collects/setup/setup-unit.rkt
+++ b/collects/setup/setup-unit.rkt
@@ -658,8 +658,8 @@
     (define (move-drscheme-to-end cct)
       (call-with-values (lambda () (partition (lambda (x) (not (string=? (cc-name (car x)) "drscheme"))) cct)) append))
     (setup-printf #f "--- compiling collections ---")
-    (match (parallel-build)
-      [#t
+    (match (parallel-workers)
+      [(? (lambda (x) (x . > . 1)))
         (compile-cc (collection->cc (list (string->path "racket"))) 0)
         (managed-compile-zo (build-path main-collects-dir  "setup/parallel-build-worker.rkt"))
         (with-specified-mode
@@ -671,7 +671,7 @@
             (parallel-compile (parallel-workers) setup-fprintf cct))
           (for/fold ([gcs 0]) ([cc planet-dirs-to-compile])
             (compile-cc cc gcs)))]
-      [#f
+      [else
         (with-specified-mode
           (for/fold ([gcs 0]) ([cc ccs-to-compile])
             (compile-cc cc gcs)))]))
diff --git a/src/Makefile.in b/src/Makefile.in
index 92bd076046..c17859d26a 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -54,7 +54,7 @@ both:
 
 # Install (common) ----------------------------------------
 
-SETUP_ARGS = -X "$(DESTDIR)$(collectsdir)" -N "raco setup" -l- setup $(SETUP_OPTIONS) @INSTALL_SETUP_FLAGS@
+SETUP_ARGS = -X "$(DESTDIR)$(collectsdir)" -N "raco setup" -l- setup $(PLT_SETUP_OPTIONS) $(PLT_ISO) @INSTALL_SETUP_FLAGS@
 
 install:
 	$(MAKE) install-@MAIN_VARIANT@