Glad your RMA went smoothly, & that you'd identified the guilty part successfully!
Do not worry about those idle temperatures. Apart from the fact that idle temps are notoriously inaccurate (being far from Tmax), you have perfectly normal readings. The real test of your cooler is load temperatures.
On a side note, for an air-cooled system, idle temps are usually a few degrees above case/motherboard temperature, which itself is usually a few degrees above ambient room temperature. So unless you live in a chiller...
Do not worry about those idle temperatures. Apart from the fact that idle temps are notoriously inaccurate (being far from Tmax), you have perfectly normal readings. The real test of your cooler is load temperatures.
On a side note, for an air-cooled system, idle temps are usually a few degrees above case/motherboard temperature, which itself is usually a few degrees above ambient room temperature. So unless you live in a chiller...