I've been using Yahoo's YSLOW to try and make my pages go faster at [AgentX](http://www.agentx.co.nz)

I am using the below compress filter. When I run the site through visual studio YSLOW says that all the files are compressed and I get an A when I view the live site it gets an E and says my files need to be gzipped. Can anyone explain?

```
    public class CompressFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpRequestBase request = filterContext.HttpContext.Request;

        string acceptEncoding = request.Headers["Accept-Encoding"];

        if (string.IsNullOrEmpty(acceptEncoding)) return;

        acceptEncoding = acceptEncoding.ToUpperInvariant();

        HttpResponseBase response = filterContext.HttpContext.Response;

        if (acceptEncoding.Contains("GZIP"))
        {
            response.AppendHeader("Content-encoding", "gzip");
            response.Filter = new GZipStream(response.Filter,
                CompressionMode.Compress);
        }
        else if (acceptEncoding.Contains("DEFLATE"))
        {
            response.AppendHeader("Content-encoding", "deflate");
            response.Filter = new DeflateStream(response.Filter, 
                CompressionMode.Compress);
        }
    }
}

```