Weird - Safari re-rendering text?

When I visit certain websites, Safari loads up normally and then after about a second, the text on the website becomes slightly distorted/thinner. This doesn't happen for all sites (facebook, macrumors, gmail are fine), but it happens for enough random sites that I think it's a Safari rendering issue as opposed to a site-specific problem.

Example 1:


Example 2:


Whenever I visit yahoo for example, I'll see "Example 1" briefly before the screen changes it to "Example 2." I prefer the first image because it looks bolder and clearer, so if this is a rendering feature of Safari, I would consider turning it off for annoyance/aesthetic reasons. Both screen shots were also taken at exactly the same size - i didn't expand one to make it the same size as the other (hence changing the look of the text).

Anyone know why this is happening or have any insights?

I'm running a 2008 aluminum macbook on the latest versions of snow leopard and safari.

Thanks!

 

Not to my knowledge, although there could've been small flash advertisements or something on the side or bottom.

I also tried going to the same sites using chrome + firefox and didn't have the same issue, so I think it's definitely a safari issue

 

anyone else know anything about this?