A couple days ago, after much research I picked up the 25" Acer H257HU IPS monitor (60 Hz, 4ms). I went from a 24" 1200p TN panel to this. At 25", the dot pitch is tiny lol.

http://us.acer.com/ac/en/...ent/model/UM.KH7AA.001

Sometimes, I notice the frame rate becomes sluggish/choppy even though the FPS are quite decent. In Fallout 4, this happens periodically. With Dirt 3, no issues (completely smooth).

I'm using an i7 920 at stock and GTX 670 4GB on the DisplayPort.

Any ideas?

No, it wasn't.  Previously, I was using DVI, now I'm using DP (1.2).  It is almost as if it feels like 10 FPS when it's actually 40 FPS, and the mouse pointer lags when you move it.  I've tried it with and without AA.
 
Even when logging into Steam, the friends who are already logged in stutter in movement when they pop up on the right.
 
 

What you are experiencing was what I had but with an older card and driver. My setup at that time was a 27 inch Overlord Tempest and an EVGA 770 classified. Prior to the release of Fallout 4 I had absolutely no problems running anything that I had at a smooth 60 FPS. (even Skyrim) V-Sync was enabled and I was running an aged driver. My thinking was that my 770 would handle FO 4 maxed out and that is where I set it. I did have to manually type in the 2560 1440 setting for my monitor as it did not do it automatically. That should have been my first clue based on past setups. 
 
It didn't take very long at max settings for me to realize that my 770 was being pushed around and if I wanted to play at this resolution and maxed out I needed some extra horse power. My current video setup now is the same monitor/resolution and a lot newer driver 358.91 with a butt kicking EVGA 980 TI SC. Problems solved and it's game on.
 
I was and still am running a Z87 ASUS Hero board with a 4770 K chip at stock speed.
 
 

NazcaC2
So, my GPU isn't up to the standard for 1440p? As I said earlier though, when I just join Steam and my online friends pop up, its animation isn't smooth. In Precison X, I get 40-50 FPS in games yet sometimes feels like a slideshow.

That's what it sounds like to me. You didn't mention what driver version you are on.
 
If Acer recommended that you return the monitor I would do as suggested.

Currently, my NVIDIA driver is:  359.06
 
GPU:  GTX 670 4GB
CPU:  i7 920 on the X58 chipset
 
It's just weird that when I'm not even playing any games and my online friends appear, they pop up from the right in like a jumpy 3-frame animation.  And, when the FPS says it's quite decent, it appears not as smooth.  I'm just confused.

Seems fixed.

Aside from the clean driver install, I've scaled the desktop to 125% because 1440p on a 25" monitor at the desktop looks quite small but looks fantastic in games. 100% sRGB is extraordinarily bright, so I brought it down to 50% brightness and it's easier on the eyes. I was debating on whether to return it and save up for the XB271HU or continue to keep it.

AA in any game at that resolution is pointless and at that size. Even 1x in Crysis 3 felt like something higher because the PPI is great.

No one? Lol.

I might have a conclusion: the brightness (or lack thereof) of my room makes the monitor seem like an eyesore. I've been reading people suggesting putting an ambient light behind the monitor to balance the light out. That, or the monitor is too small and several other factors as listed previously...

Thanks, Dave. What do you set your brightness at? (even though all monitors are different)

No problem
No problem
No Problem 
 
I believe my Swift is around 70%, the other half's I think is around 35%, she says my Swift is too bright, but then again, her glasses are thick, like the bottom of a glass soda bottle, so bright light from screens REALLY jumps out at her.
 
*edit*
Oh yeah, I also had to turn down my gamma a bunch for my Swift as well.  Now, no eye strain, and wow other monitors look laggy after 144Hz.

I run my Swifts brightness at 26% with contrast at 50%.  Looks very good...

Thanks all. What ambient light do you have/recommend?

We have potlights (2) above my computer but they are warm colours, unlike the massive colour-blast from the monitor. Lol.

I set my Acer G257HU 1440Hz IPS at 22% brightness and leave the contrast and gamma alone. I do photography and that brightness level gives me accurate tones and brightness when I print (meaning what I see on my screen is what prints) Plus, I take the extra step of calibrating my color with a Colormunki Smile.
 
I am also running Win 10 which comes with Dx12 (even though it's not optimized)

NazcaC2
I've gotten used to it now. Sitting behind a TN monitor for a few years is like getting shell-shocked when you sit in front of an IPS screen. For games, I change the monitor profile to Normal (100% brightness) and use my custom User profile for other tasks.

Good to hear. I never crank up past the 22% although I might bump the gamma up a little. TN's tend to have the brightness cranked way up by default - almost painful sometimes, as you've learned.
 
Cheers