*I suggest you SAVE this information. I think it's useful.
I have a U2711 monitor. It's 27" @ 2560x1440. I also have a GTX680 and have extensively tested things.
POINTS:
1. You mention an "overclock" on the monitor. That implies you're looking at one of the cheap Korean screens. STAY. AWAY. The quality of these screens is very poor and the odds of getting dead pixels are very high.
The U2711 from Dell is quite expensive still. If you want a 27", 2560x1440 screens there a couple for about $800 you can research. NCIX has links (there's about three), an Asus, Samsung and another one I think.
2. 2560x1440 and Desktop.
My desktop is 2560x1440 scaled by Windows in the settings by 40% larger which I think is optimum. You'll ALSO want to use CTRL + Mouse Scroll in web pages to adjust the ZOOM LEVEL (usually too small).
3. 2560x1440 vs 1920x1080 Gaming:
2560x1440 in most games does NOT look better. There is also a big performance hit of roughly 30% (varies). So I rarely use it. I concentrate on hitting a solid 60FPS with VSYNC (or Adaptive VSYNC) and if necessary tweak the quality settings to achieve 60FPS 90% or greater of the time.
Games that look BETTER tend to be top-down games like Diablo 3. It's the HUD elements that look far better, especially the text may be sharper. I can achieve 60FPS at 2560x1440 easily with my GTX680 (and could on my older HD5870 as well).
**The bottom line is do NOT play a game at 2560x1440 unless you can ALSO run at 60FPS with maximum quality.
Another example of NOT using 2560x1440 is SKYRIM. The ONLY difference would be a very small increase of the HUD sharpness. Even with a GTX680 when I add the HD texture pack, trying to run at 2560x1440 would drop me below 60FPS.
4. PHYSX:
PhysX is a mixed bag. Even with a GTX670/680, many games easily drop below 60FPS with PhysX on so you have to make a choice:
a) run without PhysX at 60FPS
b) run WITH PhysX at 60FPS but drop the game quality
c) run WITH PhysX and high quality but at a LOW FRAME RATE
Personally, I don't think the additional eye candy is worth the sacrifice in most games. Borderlands 2 seems to work quite well and apparently a GTX670 can play High PhysX, Max quality at 1920x1080 and still achieve 60FPS.
**So it's a good idea to run FRAPS while setting up a game and tweaking it.
5. BATMAN ARKHAM CITY:
I thought I'd add this since the game is so popular. It has coding issues, and if you dislike stuttering (who doesn't) then:
a) Disable PHYSX
b) Disable the DX11 features (tessellation and HBAO or whatever).
I've tested Batman AC extensively and the above is the only way it's fun to play the game. The PhysX weather effects cause such drops that you stutter when trying to grapel or glide. No fun.
6. CPU and RAM:
An i5-750 at stock speeds is sufficient for a GTX670/680 for most games. Overclocking it while handle the remaining games AFAIK. The best gaming CPU, IMO to buy today is the i5-3570K. You don't really need to overclock it though. Don't spend any more as a gamer.
The ideal amount of RAM is 8GB (i.e. 1600MHz DDR3) such as 2x4GB for about $40 or so. More will not provide a gamer any benefit.
7. 2GB vs 4GB:
For a single monitor up to 2560x1600, 2GB is plenty. I saw the above argument. There are RARE exceptions such as heavily modded SKYRIM. Keep in mind though that heavily modding SKYRIM also reduces the frame rate. You can easily keep piling on mods with super HD textures but it's better to choose a few, efficient ones.
FYI, Vanilla SKYRIM + Official HD Texture Pack peaks at 1.5GB of VRAM (Video RAM). It can use a card with less but you'd have minor slowdowns while buffering new textures. I wouldn't recommend the HD Texture Pack anyway without better than an HD5870.
8. Which GTX670??
Here's a list of THREE GTX670's as well as the GTX680 that I own and love. I have several games that make full use of this graphics card so if you think it's overkill, think again. (Witcher 2, BF3, Skyrim, Crysis 2, Bulletstorm, Total War Shogun 2, Batman AC, Metro 2033 and several others).
To be clear, my ASUS GTX680 TOP card will run all of the above games in better graphics quality than any GTX670 can do. Skyrim is arguable, but since i have dropped below 60FPS and it's not even modded beyond the official HD pack I included it.
Card links:
670's:
http://us.ncix.com/products/?sku=71107&vpn=GV-N670OC-2GD&manufacture=Gigabyte
http://us.ncix.com/products/?sku=72914&vpn=N670%20PE%202GD5%2FOC&manufacture=Others&promoid=1393
http://us.ncix.com/products/?sku=71741&vpn=GTX670-DC2T-2GD5&manufacture=ASUS
GTX680 ASUS TOP:
http://us.ncix.com/products/?sku=71119&vpn=GTX680-DC2T-2GD5&manufacture=ASUS&promoid=1389
**Awesome REVIEW of Asus 670 TOP**
(the 680 is identical, except about 10% average faster and is a 3-slot card)
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/55270-asus-gtx-670-directcu-ii-top-review.html
Make sure to read the final comment.
SUMMARY:
- avoid cheap Korean 2560x1440 screens
- if buying a 2560x1440 screen get one of the Asus, Samsung or other quality brands for about $800
- 1920x1080 should still be used for most games due to performance hit with minimal quality benefit
- 2560x1440 is recommended for games like Diablo 3 if you can achieve 60FPS, full quality due to the sharper HUD text.
- 2560x1440 needs to be scaled for desktop use (Windows settings)
- GTX670 or GTX680, buy a quality brand with good cooling solution (less noise)
- at $540, the Asus GTX680 TOP card is arguably the best single GPU card. It's simply an awesome card and worth considering.
- at $440, the Asus GTX670 TOP is an excellent card. It can play MOST games at full settings but not all so it really depends on the games you play and your budget.
- PHYSX is a nice feature, but the performance hit can be so huge it's not worth using.
- Finally, I advise you always TWEAK your game to get 60FPS most of the time. VSYNC or Adaptive VSYNC.
Good luck!