diff --git a/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh b/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh
index 034c28138a756..bea728d0459b3 100755
--- a/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh
+++ b/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh
@@ -13,9 +13,35 @@ expiration_date=$(date -d '8 hours' --iso=minutes --utc)
 function join_by { local IFS="$1"; shift; echo "$*"; }
 
 REGION="${LEASED_RESOURCE}"
+
+# m6a (AMD) are more cost effective than other x86 instance types
+# for general purpose work. Use by default, when supported in the
+# region.
+IS_M6A_REGION="no"
+if aws ec2 describe-instance-type-offerings --region "${REGION}" | grep m6a ; then
+  IS_M6A_REGION="yes"
+fi
+
+# Do not change auto-types unless it is coordinated with the cloud
+# financial operations team. Savings plans may be in place to
+# decrease the cost of certain instance families.
+if [[ "${COMPUTE_NODE_TYPE}" == "" ]]; then
+  if [[ "${IS_M6A_REGION}" == "yes" ]]; then
+    COMPUTE_NODE_TYPE="m6a.xlarge"
+  else
+    COMPUTE_NODE_TYPE="m6i.xlarge"
+  fi
+fi
+
 # BootstrapInstanceType gets its value from pkg/types/aws/defaults/platform.go
 architecture=${OCP_ARCH:-"amd64"}
-arch_instance_type=m6i
+
+if [[ "${IS_M6A_REGION}" == "yes" ]]; then
+  arch_instance_type=m6a
+else
+  arch_instance_type=m6i
+fi
+
 if [[ "${CLUSTER_TYPE}" == "aws-arm64" ]]; then
   architecture="arm64"
 fi
@@ -29,7 +55,8 @@ workers=3
 if [[ "${SIZE_VARIANT}" == "compact" ]]; then
   workers=0
 fi
-master_type=null
+
+master_type=${arch_instance_type}.xlarge
 if [[ "${SIZE_VARIANT}" == "xlarge" ]]; then
   master_type=${arch_instance_type}.8xlarge
 elif [[ "${SIZE_VARIANT}" == "large" ]]; then
diff --git a/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-ref.yaml b/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-ref.yaml
index f5bf638f52ee2..98e4192cc7bec 100644
--- a/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-ref.yaml
+++ b/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-ref.yaml
@@ -25,10 +25,10 @@ ref:
       in some regions or accounts due to quota issues.
 
   - name: COMPUTE_NODE_TYPE
-    default: "m6i.xlarge"
+    default: ""
     documentation: |-
-      The instance type to use for compute nodes (e.g. AWS https://aws.amazon.com/ec2/instance-types/). We use a 4 core worker to match the median configuration of the fleet.
-      Do not change family type without consulting with FinOPs about active AWS savings plans.
+      The instance type to use for compute nodes (e.g. AWS https://aws.amazon.com/ec2/instance-types/). When "" (default),
+      the step uses the lowest cost 4 CPU / 16G supported worker instance type for the region.
   - name: OCP_ARCH
     default: "amd64"
     documentation: |-