Is my wireless card busted?

I just got a new company laptop...Latitude D620 with a Wireless 1490 802.11a/g mini-Card. I was able to get connected to my home wireless network with connection speeds showing up at 54 Mbps, but pages were loading so SLOOOOOOOWLY. So I popped in my old 1350 from my 3 year old Inspiron, changed the setttings to connect using the new card and voila - pages are loading as fast as lighting.

 

So now I know its not my home network that is the problem or that I'm picking up a neighbors network like my company IT guys told me....but does it sound like something isn't configured properly on the 1490 minicard or does it sound like it might be faulty?

 

Any help would be appreciated....I'm not an IT professional so I'm trying to explain this the best I can.

 

I am perplexed....my IT guys were telling me that my home network