3mb dsl in Firefox, 11mb in Chrome....help??

(hoping I've popped this in the right forum as my DSL is working fine but I may have a software problem)

I'm not an IT novice and have found this site helpful on many occasions - but I am perplexed by something happeneing on just one of the PCs in my house.

I run and download the same content in Chrome at 10/11mb dsl speed and the same in Firefox prodice only a third of that in ters of downloading and speed testing.

Am running Firefox now in Safe Mode/No Add Ons and it doesn't seem to make a difference.

Sky broadband unlimited, 3.2ghzintel celeron, 1.5gb ram.

A.M

I have a similar situation. I have 6 Mbps service with ATT U-verse. When I run ATT's own speed test in Firefox, it shows 3.2 Mbps consistently. But when I run ATT's speed test in Chrome, it shows 5.8 to 6 Mbps. How is that possible? Anybody?

Oops! I just ran ATT's speed test again in Chrome, and it hit 12 Mbps! That's obviously a mistake. So now I'm wondering if ATT's speed test and Chrome have issues with each other. Look forward to your comments.