I recently put some parts together on newegg because I am building a new computer, I have never built a gaming computer and I have a budget of $600 but I would like to try and keep it under 550. I am not going to be doing any hardcore gaming, I just plan on running call of duty and other FPS games on medium graphics.
Also I am going to need a new monitor for the new graphics card as my monitor only supports 1280x1024 and I want a samsung monitor but I have no clue what to look for in a gaming monitor, my budget on the monitor is $220.
ASUS has a better warranty for things like dead or stuck pixels. this is a good LED gaming monitor. for gaming you want to look at the response time and latency. latency is almost never listed so you have to go with word of mouth and reviews. for response time you want 5ms black to black or 2ms gray to gray.
this is a good budget gaming system with a i5 SandyBridge quad core. it will be far superior to the one you have above. Not sure if you were attached the case you picked out or not. I used Z9+ which is a better case imao. it comes with 4 fans and a fan controller. it runs very quiet and keeps things cool. I think it looks good too. I ugraded your GPU to a 550Ti, this will give you better peformance with the larger monitor. the GTS 450 would struggle in games at 1920x1080, you'd have to turn down the graphic settings.
Also what does black to black and gray to gray mean?
Black to black (BTB) and gray to gray (GTG or G2G) are the time it takes a pixel to change color (transition) then back again
BTB is a full black full white full black transition and GTG is more like almost black to almost white to almost black - these are usually to the point that the human eye would call it black then white then black. the quicker the transition time the less "Ghosting" the monitor will have, the better to game on.