要计算AWS RAM利用率，您可以使用AWS SDK提供的CloudWatch API来检索RAM的相关指标并进行计算。以下是一个示例代码，使用AWS SDK for Python (Boto3)来获取RAM的利用率指标：

import boto3

def get_ram_utilization(cluster_name):
    cloudwatch = boto3.client('cloudwatch')
    
    response = cloudwatch.get_metric_statistics(
        Namespace='AWS/RAM',
        MetricName='Utilization',
        Dimensions=[
            {
                'Name': 'ClusterIdentifier',
                'Value': cluster_name
            }
        ],
        StartTime=datetime.utcnow() - timedelta(minutes=5),
        EndTime=datetime.utcnow(),
        Period=300,
        Statistics=['Average']
    )
    
    if 'Datapoints' not in response:
        return None
    
    datapoints = response['Datapoints']
    if len(datapoints) == 0:
        return None
    
    utilization = datapoints[-1]['Average']
    return utilization

# Example usage
cluster_name = 'my-ram-cluster'
utilization = get_ram_utilization(cluster_name)
if utilization is not None:
    print(f"RAM utilization for cluster {cluster_name}: {utilization}")
else:
    print(f"No RAM utilization data available for cluster {cluster_name}")

这个示例代码使用了get_metric_statistics方法从CloudWatch获取了最近5分钟内RAM利用率的平均值。您需要替换cluster_name为您要查询的RAM集群的名称。如果成功获取到数据，将打印RAM利用率值；否则将打印相应的错误消息。

请确保您已正确安装并配置了Boto3库，以及正确配置了AWS凭证。