diff --git a/qemu/Config.in b/qemu/Config.in
index 43ee8f7e..f3f8e1b2 100644
--- a/qemu/Config.in
+++ b/qemu/Config.in
@@ -29,8 +29,8 @@ endchoice
 
 config QEMU_MACHINE
 	string
-	default "qemu-system-aarch64 -M virt -cpu cortex-a72 -m 256M"               if BR2_aarch64
-	default "qemu-system-x86_64 -M q35,accel=kvm -cpu host -enable-kvm -m 256M" if BR2_x86_64
+	default "qemu-system-aarch64 -M virt -cpu cortex-a72 -m 256M"   if BR2_aarch64
+	default "qemu-system-x86_64 -M q35,accel=kvm -cpu host -m 512M" if BR2_x86_64
 
 config QEMU_KERNEL
 	string