I’ve been running a release candidate version (build 6001) of Vista Service Pack 1 for a few weeks now and by far the biggest advantages have been ‘performance’ related. What’s funny is there were a slew of performance-related pre-SP1 hotfixes released for Vista in the past year, none of which had resolved any of my specific issues. The ‘performance’ bump I’m seeing is more perceived, as Microsoft has finally fixed some glitches which were causing Vista to hang-out and wait for something to most likely timeout, and then proceed on with what it needed to do.
On the top of my list was this major annoyance, which Mark Russinovich discovered well over a year ago. I found that blog entry the first week I was running Vista as that issue was driving me up a wall. I habitually open and close Explorer windows and waiting 10-15 seconds for the window to draw and response every time was getting on my nerves. I lived with it for over a year, wondering why no separate hotfix was released for this, while waiting for SP1 like everyone else.
As a proof of concept I decided to run some captures using Network Monitor to see exactly what was happening. The typical scenario is I am logged into my laptop using cached credentials for my domain account, and have no network access to the domain as I’m usually off-site. No VPN client is running or connected. I began capturing network packets.
Whenever an Explorer windows is opened, the window begins to draw, but no content appears for at least 5-10 seconds, sometimes longer:
Once the window finally responds, I can see that the bread crumb displays my simple user name. This is the typical behavior when not connected to my domain.
A look at the network packets in the capture data show a couple records which verify the delay is related to a request to connect to a domain controller:
|1||18.104.22.168||192.168.10.10||DNS||Standard query SRV _ldap._tcp.dc._msdcs.schertz.local|
|2||192.168.10.10||22.214.171.124||DNS||Standard query response, No such name|
|3||126.96.36.199||192.168.10.10||DNS||Standard query SRV _ldap._tcp.1153…ee8.domains._msdcs.schertz.local|
|4||192.168.10.10||188.8.131.52||DNS||Standard query response, No such name|
When connect to my corporate network (either locally on-site or remotely via VPN) there is no delay and my Display Name is properly shown in the bread crumb.
But now that I’m running SP1 for Vista, this issue has completely vanished. All browser windows open nearly immediately, and my bread crumb displays correctly as well. A network capture no longer shows any DNS referrals for domain controllers. I’ve also seen network file-copy performance increase as their is no long ‘calculating’ period when moving even very small amounts of data. Yeay!