3 second lag when making http request to localhost

> I'm using Windows Vista Business on a brand new Lenovo x61s laptop with 2G
> RAM and a 1.6Ghz Intel Core Duo CPU.
>
> I'm running a web server on the laptop and am finding a strange lag of about
> 3 or 4 seconds when I try to access local content (i.e. short text or html
> files on my C drive served by my local web server). In contrast, access to
> remote websites is lightning fast with this machine and connection, and
> applications seem to be performing well on the machine overall. Local http
> requests are the only problem so far.
>
> I've tried a couple of web servers (including Apache) and have seen the
> problem in all of them. I've tried accessing the content in both IE and
> Firefox. I've tried URLs of all the following forms:
> http://localhost/mylocalfile.txt, http://127.0.0.1/mylocalfile.txt,
> http://<my-pc-name>/mylocalfile.txt.
>
> The best advice I found in a couple of hours of web searching was 1) set the
> network.dns.disableIPv6 config property to true in Firefox [didn't help, and
> as mentioned, the problem surfaces in IE as well], and 2) turn off TCP
> autotuning with "netsh interface tcp set global autotuning=disabled" [didn't
> help].
>
> Is there anything I'm overlooking that would explain why access to a _local_
> site would be slow when the machine performs well overall and remote sites
> are loading quickly?