Slow Internet Through Router

[Chrums]

Hello,
I have Comcast 20Mbps internet. When I'm on the Mac partition of my computer, I get 15Mbps download and a ping of less than 10 on speedtest.net. When I'm on my Windows partition, I get a ping of around 250 with a download speed of 1.5Mbps. I read posts where people said disabling their firewall helped, so I disabled mine and it made no difference. Does anyone have any idea what could be causing this?

 

[jgutz2006]

Are you plugging directly into the comcast modem being used as a router or do you have a separate device plugged in between PC/Modem