Memory usage keeps Increasing ?!?

[badogblue]

I'm running Windows 7 Home Premium with 2GB ddr3 memory. The problem is that when running Internet explorer or Firefox the memory for each process continuously increases. Each time a new page is loaded (same tab) more memory is used. After 5 min or so the memory usage is around 130mb and is over 500mb in 1hour, with only 1 tab!

I have run with add-ons disabled and in safe mode with little difference. I have also done a scan with Norton to no avail.
Any advice would be most appreciated! Thanks.

 

[badogblue]

Just realized I made a serious typo, I meant to say that after 5 min it uses around 130mb and over time gets as high as 300mb or more, with just one tab open.

 

[badogblue]

Found this graph that shows average memory usage with 1 tab open. How is it then when i run IE9 with one tab open, memory usage reaches over 300mb.
Could this be "memory leak" as it never decreases, just remains constant untill a new page is loaded were it increases by 20-30mb. Though this happens with every website!

Any help would be most appreciated.