I watch youtube or different kinds of livestreams in HD a lot. And the last 2-3 month I'm having a problem watching them in Firefox because I get a terrible lag if I open 2 or more tabs with a video inside. As I am typing this message I've had about 5 terrible freezes (I've opened 2 livestreams in my tabs). Sometimes they just crash and I have to restard the page to go on watching, but most of the time they are lagging like they are lacking FPS and it's unwatchable. I tried cleaning the cash and using different versions of Firefox, I tried the new beta (17) and it's the same. My personal opinion is that Shockwave Flash fault, but I reinstalled it and tried different versions so many times, so I don't know what else to do. I like using Firefox, but I can't do it anymore. I tested the same thing in Chrome and it didn't lag a bit even if I open 10 videos at a time.

My system is: Videocard PCI-E 2.0 ZOTAC GeForce GTX 560Ti, ZT-50303-10M, 1Gb, GDDR5 HDD SEAGATE SV35 ST31000526SV 1Tb SATA III Motherboard ASUS P8H61/USB3(3.x) LGA 1155 DDR3 8 Gb CPU INTEL Core i5 2500, LGA 1155 Windows 7 64 bit Firefox 16.0.1