Where子句和Join的LINQ顺序

以下各项之间是否存在性能差异:

ctx
   .Students
   .Join(
      ctx.Countries, 
      q => q.CountryId, 
      q => q.CountryId, 
      (c,s) => new { c,s })
   .Where(q => q.c.CountryName= "USA")
   .Select(q => q.s.StudentName)
   .ToList();

以及:

ctx
   .Students
   .Join(
      ctx.Countries.Where(q => q.CountryName == "USA"), 
      q => q.CountryId, 
      q => q.CountryId, 
      (c,s) => s)
   .Select(q => q.StudentName)
   .ToList();

如果是,哪种查询更可取?