Strange High Ping in Win7

Greets to all!

I have an odd high ping situation I can't figure out. I have two Windows boxes on the same home network. The older (5 yrs) box is running Win XP. The newer box is running Win 7 (64b) Enterprise. Lately I've been getting high 500ms + pings from everywhere on the Win7 box. I'm 20 miles outside Philadelphia, and getting 512ms pings from Speedtest.net The old XP box shows 18ms pings! Yet the thru-put is around the 10mbs I should be getting. 20mbs to NYC.

Comcast has come in and replaced the modem and cleaned up some of the connections, and still get the same 512ms ping to Phila in the Win7 box. I also notice a lot of "waiting for xzz.com..." when using Firefox or Chrome on the Win7 computer.

Interestingly, Pingtest.net shows the expected 18ms ping to Phila! Other speed test sites show the 500ms pings... so I don't think it is Speedtest.net.

Anybody have any ideas what might be causing this Win 7 box to show such high pings on Speedtest?

=Alan R.

Yes - have done that. Totally disabled Bitdefender and Prevx - no change. Have tried TCP Optimizer - now restored to default settings - no effect - still big pings.

Next I'll try booting in Safe Mode w/network and see if I can get to Speedtest.net to run.

Any thoughts as to why I get a good ping with PingTest.net and a bad one with SpeedTest?

=Alan R

Yes - the cable modem goes to a Vonage phone interface and router, and then thru a Gigabyte switch to the Win7 box and the old XP box is on the same hookup. As I saidk the XP box gets the correct ping, but Win7 does not. Also, I have hooked the Win7 box directly to the cable modem, bypassing the router and switch, and still got the 500ms pings.

I just seems like some TCP/IP setting in Win7 is messing things up. Then there is the odd factor that the website Pingtest.com returns low pings to all sites, but when I go through Speedtest.net (and other speed test sites) I show the high pings. Very funky indeed!

=Alan R.

Have just booted Win7 into Safe Mode w/network, and ran the Speedtest.net test. As expected - the ping to Philadelphia is now 18 ms like it should be. Other thru-put went through the roof along with the better ping. I also went to the Wordpress-based site I'm working on and all the admin level page-changes, which are always draggy under full Win7 now snapped right in.

Now booted back to full Win7 Enterprise and the ping to Phila goes back to 512 ms.

So.

Some setting in Win7 is f***ing with my ping and web access.
I've rounded up (and executed) all the usual suspects, and still no fix...

Any new ideas greatly appreciated.

=Alan R.