Will this cpu bottleneck?

i have a amd athlon 64 x2 4000+ and a 9600gt oc'd graphics card. in left for dead i get 60-130 fps on low settings and 120fps on css. was told im getting low fps/fps drops due to my cpu bottlenecking, will this cpu fix that, http://www.newegg.com/Product/Prod [...] 6819103234
asking because the low cache, i have a dell and cant use am2+ cpus i think.

I would ask on one of the dell forums if someone has used the 5600 brisbane on your board. It will help your framerates some. A faster video card would also help, but that might require a better power supply. Pc power and cooling makes a dell replacement power supply for aroung $60-70 sold at newegg.

You might as well fork up the extra $2 and get the 7850BE. Even though it is 100mhz slower than the Brisbane 5600+, it'll be equal to or faster in most games.

Athlon X2 7850 BE

That sucks. More than likely it only takes a BIOS update. However I haven't bought an OEM computer like Dell for the longest time, so I don't how often they refresh their BIOS updates. I would go ahead and check with Dell if they have a newer BIOS that will allow the Kuma to work.

will http://www.newegg.com/Product/Prod [...] 6819103278 be much of a upgrade as for as gaming?

my current is 2.1ghz dual. someone from dell said somewhere that the 6000+ will work, will the 6000+'s 2mb cache help alot better then the 5600+'s cache? i just domt want to bottleneck with my 9600gt.