diff --git a/appveyor.yml b/appveyor.yml
index 0b79a3d967ed7..2066b61f37e24 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -3,6 +3,8 @@ environment:
   matrix:
   - ARCH: "i686"
   - ARCH: "x86_64"
+    JULIA_CPU_CORES: 1
+# Run win64 tests in serial for now to avoid #7942 causing timeouts
 
 # Only build on master and PR's for now, not personal branches
 # Whether or not PR's get built is determined in the webhook settings