Large amounts of Internet streaming video traffic are being delivered using HTTP to leverage the existing web infrastructure. A fundamental issue in HTTP streaming concerns the granularity of video objects used throughout the HTTP ecosystem (including clients, proxy caches, CDN nodes, and servers). A video may be divided into many files (called chunks), each containing only a few seconds of video at one extreme, or stored in a single unchunked file at the other. In this paper, we describe the pros and cons of using chunked and unchunked videos. We then describe a methodology for fairly comparing the performance implications of video object granularity at web servers. We find that with conventional servers (userver, nginx and Apache) there is little performance difference between these two approaches. However, by aggressively prefetching and sequentializing disk accesses in the userver, we are able to obtain up to double the throughput when serving requests for unchunked videos when compared with chunked videos (even while performing the same aggressive prefetching with chunked videos). These results indicate that more research is required to ensure that the HTTP ecosystem can handle this important and rapidly growing workload.