I have an old dell with a 2.4 ghz pentium 4 processor and 1256 MB of DDR400 RAM. I have a 1080p monitor which i have been using for my xbox, and i was wondering if i would be able to upgrade my graphics card to an AGP HD4650 once i upgraded my power supply to 450 watts. If so, would i be able to play newer games like Left 4 Dead 2 or Team Fortress 2 at a decent framerate with at least medium settings at a resolution of 1080 x 1920? For reference i provide this video of someone playing left 4 dead 2 on the highest settings with a 1280 x 1020 monitor and a 2.8 GHz processor, but the same graphics card i hope to get.
Thanks for all the advice, and i know that it would make sense to upgrade the processor and all, but I do have a designated gaming computer; the only problem is that that is staying at my dad's, while i am at my mom's most of the time, using nothing but the netbook on which i am now typing (I'm 17.) Also, would it make a difference if i upgraded the processor in addition to the ram, or would it just be cheaper to buy a new mobo/processor combo (links would be very helpful.)
The HD4650 works great for Tf2/L4D2, however your processor will bottleneck it to no end. I have a C2D E1400 overclocked and I'm still getting a huge bottleneck. If I were you, I'd get a new mobo+CPU+Ram + HD4650 PCI-E.
Well, the GPU should be o.k for L4D and TF2, but the rest of your system is another matter. Upgrading to 2GB would probably be a good idea. It is way past time to upgrade your CPU though. Even so, with 2GB and a 4650 your system should be able to chug along on L4D2 on medium/medium-low