Anyone having trouble with firefox?

I've a new 2012 matchbook air for about the last 3 months and in that time I've had to do a complete re-instal twice

I don't have an iTunes account that stores pictures/music or documents I basically use it for internet and emails only. It runs okay for about 3 weeks then starts slowing down substantially an with a lot of the multicolour spinning disc

i've continually cleansed the cache, history etc and use cc cleaner daily. I've also used clamxav to check for malware all are okay and no problems found but it always slows after a couple of weeks and by a lot

Other than taking it back I'm unsure what else to do?

as a precaution I've removed firefox and gone back to safari os and it seems quicker but unsure if this is just a browser problem

Firefox seems to be the culprit for the laggy speed on my otherwise rock-solid Lenovo laptop (Core i3, 4GB, Windows 7 64).... Quick look at memory allocations for running applications shows that it's using a hell of a lot of memory with just 3 tabs open.

Only reason I am still running it is because it's the only browser that works properly on my webshop admin.

It is probably worth doing a scan for Malware and Spybots. A lot of these are not flagged by antivirus software, and will slow down your browsers speed considerably.

I use Spybot Search and Destroy, and Malware Bytes, both are free. Make sure you update them once a week, and you will be fully protected (along with your AV software).

firefox just uses a bunch of ram.i get warnings all the time about it.may i suggest chrome?