Monitor confusion

OK i need some help here and i turned to everyone here because it seems to be credible. I just ordered a new computer and its on the way and i want to get an amazing monitor because it has blu ray. But i have posted other places and people say that the resolution my affect the smoothness that the monitor runs. What i mean is there may be lag. I will be using my computer for gaming buy not hardcore just like the sims 3. So here are my specs an a few monitors i am looking at.

Specs:
HP AMD Phenom II Quad Core
8GB RAM
3.0GHz
750GB hard drive
NVIDIA GeForce 9800GT 512 dedicated
blu ray

Monitors:
23in HP monitor
1920x1080 resolution
5ms response

OR

24in HP monitor
1920x1200 resolution
5ms response

Which one will work better with my computer. I have gotten many mixed answers some say it doesn't matter others say it does. Im really confused as you can tell computers are not my forte. Any help will be greatly appreciated Thank You!!!

1. You are correct. In several applications, including gaming, the higher the resolution, the more a graphics card will be taxed.

2. Your system is very good. It doesn't top what some hardware enthusiasts have, but it is definitely better than what your average Joe is using.

3. Those resolutions are quite high; however, if you are looking at games like The Sims 3, you should be fine. Importantly, some games, especially first person shooters like Crysis and Far Cry 2, are more demanding than others. While The Sims 3 is not out, given the flexibilty of The Sims 2 and the assumed widespread appeal of The Sims 3, I imagine that your system will be more than fine.

4. Both monitors have about the same resolution. As a result, from a performance standpoint, it really doesn't matter which one you choose. The Sims 3 at 1920 x 1200 will most likely be a slower than The Sims 3 at 1920 x 1080, but it won't exactly be night and day. More like a frame or two.

5. Benchmarks / reviews in case you are interested:

9800 GT - http://www.hardwarecanucks.com/for [...] palit.html

Phenom II - http://www.anandtech.com/cpuchipse [...] spx?i=3492

Oh and for the contrast ratio i do believe for both that its somewhere like 1000 to 1 and then dynamic is around 3000 to one.....i also was looking at a samsung 24in monitor that had 1920x1200 resolution and its contrast ratio was something like 10000 to 1 or someting like that. It was really high. But i read alot of crappy reviews and it also didn't perform as well as the HP monitors in several tests.

Ummm went to best buy and i don't have an SLI graphics card so i am gonna be using GeForce 9800GT. And yes my graphics card does have an HDMI out im guessing....i haven't gotten it yet it should be coming in a few wks. I know that it has and HDMI out i just don't know where it is at?

So am i gonna be ok and how high of settings do you think i can run the sims 3 on this computer with the 24in monitor with 1920x1200 resolution?
I mean i want to be able to play at least on high...very high is not that important to me really i mean i won't complain if it does play at that high but i doubt it. So what do you guys think. I mean the sims doesn't have very high system specs @ all. Really people with 3 yr old computers or more will be able to play. Thanks again for the help.

If you're going to be doing a lot of movie watching, you might want to go with the 1920x1080 monitor, as that's the resolution blu-ray discs play in. 1920x1200 would work, but it'd be letter-boxed in fullscreen.

As for your game performance, Sims 3 is going to have very modest requirements - you will be perfectly fine with either monitor. The difference between 1920x1200 and 1920x1080 is very small (only~10% difference in pixels) so any performance difference will be unnoticeable.

some programmers really like being able to do it. Other then that I can't think of anything else.