Samsung CF791: My Review

Xorak

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Jun 7, 2013
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Let's get my system specs out of the way first: i5 4690k @ 4.5, 16gb DDR3 2400, Sapphire Fury Nitro @ 1130/520. SSDs for system and game drives.

It's been a long wait. I've been interested in 21:9 for a while. When I learned of the CF791's inception and proposed specs, I knew I'd have to hold off until I saw what this thing could do. I finally got it on my desk about a week and a half ago. I knew I'd need to spend some time with it before I said too much about it. I've now spent two full weekends glued to it as much as possible.

I've had an ASUS MG279Q for over a year, so that's going to be my benchmark. Very briefly on that, it's quick, has a wide freesync window, spot on color and pretty decent contrast for an IPS. It's weaknesses are underwhelming black levels and light bleed at the corners, underwhelming sharpness, with the actual sharpness control locked out in the only usable preset mode. Over all, a very good 27" monitor for any activity. Highly recommended.

This was going to be a pre-review. Going back to make some edits, I realize I've said quite a bit. I'm not completely finished making up my own mind, frankly. This morning, I finally decided to also order an Acer XR341CK to compare. Why? Let's dive in.

The good:

As advertised, the colors are indeed very vibrant. In many cases they make an image or scene look very natural, rather than over-saturated. In other words, they're the real deal. For example, I fired up a couple movies to try out full screen 21:9. I mostly managed to watch what I intended and not get sucked in. But I watched iRobot all the way through because it's been a while and it really looked good. Then I watched Terminator 2. I don't know quite what to say. T2 was just straight up filmed for this monitor. It looked so friggin natural I couldn't look away!

I can't gauge the color accuracy scientifically, but I would say they must be very close. More than accurate enough for content consumption. It's not far off from my MG279Q, which is said to be on par with many professional products. A content creator will still want to run instrumented measurements first.

It has moderately darker blacks than my IPS screens, but with much better black uniformity across the screen, ie, no bleed at the corners. This provides noticeably higher contrast, which may contribute to the higher perceived color space.

In addition, the image is very sharp. This was my biggest problem with my MG279Q, which seems a tad blurry considering its high pixel density.

All these factors combine to create an image that's very compelling and really feels like I could reach out and touch it. I've read reviews of other VA screens people keep saying the extra contrast gives the image a much greater sense of depth. I can now agree completely on this point.

On the refresh rate side, it does indeed go from 48 to 100hz (in the ultimate engine setting) and freesync's LFC does function. Motion blur also seems very low, definitely less than my MG279Q. I'm not terribly picky about this myself. I know everyone else is crazy about low blur and I agree to a point. To my eyes though, a little motion blur is natural and makes motion appear smoother. No complaints here from me. I think most will be very happy with the low blur. Come to think of it, the MG279Q has one higher over-drive setting than what I actually use, because I felt it robbed too much fluidity and made movement less natural. I don't feel strongly that way about the CF791, which is a good thing!

Finally, the build quality seems very good. The base is nice and heavy and the screen doesn't shake when I'm pounding on my keys in the heat of battle. I wasn't too enthusiastic about the aesthetics with all that white plastic. But when I'm sitting in front of it, all I really see is the dark silver of the bezel and base. So really, I'm fine with it. Someone mentioned that they liked white backed monitors so they can add some kind of ambient lighting behind and have it reflect more to the surrounding walls. Neat Idea.

I wish I had a decent camera or something to try and show this thing off with. It feels a little inadequate to just sit here and say, "Yup X, Y and Z are pretty good." Suffice it to say, I think the screen accomplishes what it set off to do. It straight up delivers a very vibrant, compelling and immersive gaming experience. The trade-offs it makes are mostly felt while not gaming. But games aren't everything, even to many gamers, such as myself and there are trade-offs.

The not so good:

The biggest thing for me, is the color shift is very noticeable, if not too extreme. Probably better than a TN, though I haven't used any newer or higher end TN panels to compare. Sitting dead center, it's hard to tell at all on lighter scenes. In darker scenes it's more noticeable but still not terrible. In either case, I can move around a bit and its clear there's no one position where I can see colors accurately across the whole screen. Again, they don't shift a lot and it's going to be a personal thing how much, if at all, this bothers you. It bothers me for sure, but I'm pretty sensitive to this. I was the very last of my friends to give up my CRT back in the day, for this reason.

The above assumes I'm on center. If I go and sit to the side, or my girlfriend and I want to sit next to each other and watch a movie, well, now it's a whole other deal. This is really a one person screen. It's fair to say it's a good compromise from having a VR set strapped to your face. You can be hugely immersed without actually being cut off from the world, so that's cool. But if you need to share with others in the room, stop reading now and go find an IPS. (Come back next week when I have the XR341CK to talk about!)

While the black levels are lower and the contrast is higher, colors close to black still get crushed. I expected this to be a major pro for the VA screen. I thought, if a 0 brightness pixel is closer to 0, then the 5 or 10 brightness pixel next to it should be easier to see, right? Well, it's not. It crushes near black colors a little worse than my MG279Q. This isn't a bad starting point by any means, but because those blacks are darker, it's more noticeable. It really stands out that it's happening at all, let alone just a little worse than what I'm used to. I had to compare several images side by side on both screens, to figure out that the black crush wasn't actually much worse on the CF791. Put another way, if I look in a dark spot on the IPS panel, like inside a box, or shadows around a character's clothing, I might see where there's a little crush going on. Because that area isn't so much darker than the areas immediately around it, I know there can't be too much I'm missing. On the CF791, where those areas drop to full black, it's a bigger drop from the surrounding areas of discernible color. So intuitively, it seems there must be much more information getting lost, when in reality, it's only a small difference. Hopefully that makes sense.

The color shift makes it that much worse though. If I look around from extreme angles, where the color washes out really bad, I can see the missing shades pop back up. So, it feels like there should actually be a lot more detail available when looking from a normal angle. But in that instance, I really can't tell how many steps are actually missing. If it's like 3 out of 256, or 15..

The next the big thing to talk about is Freesync flickering. Maybe this should have been first? It might be the least subjective... Either way, here it is. Yes, it happens. I think this is why AMD recommends a freesync range of at least 2.5x the minimum refresh rate, even though 2x works.

In a game, it will occur when I'm straddling that 48-50 fps barrier. During that time, the actual refresh rate of the monitor is oscillating frame to frame between ~48 and ~96-100hz and it can't maintain a consistent light level. So how bad is it? It's not a huge light/dark transition. I have a really hard time seeing it in a dark scene. If I'm crossing over the 48hz threshold quickly, I don't see it at all. Most of the time, in most of my games, it's a non issue.

Fallout 4, with my settings, my mods and my hardware, is the one game so far that winds up sticking right around these frame rates with any regularity. While it can get pretty distracting at certain times, it's still not exactly game breaking. Even in Fallout, it's not a big deal when I'm not looking for it. I'm not going to get stuck with it flickering for more than a second or so if I'm actually playing the game and moving around the environment. In the off chance that I do, then yeah, it sucks.

The more bizarre issue I found, is some full screen video applications like YouTube or Netflix, will flicker all the time. Sometimes even cause the screen to black out, like it's been pushed out of range. I say this is bizarre because a) I didn't realize freesync would be active here and b) I figured almost all video these days was 30 or 60 fps. Neither of which are near 48. But maybe they're running old school 24 fps and trying to set the monitor to 48hz on the dot and it can't deal. I need to see if I can mod the minimum refresh rate down to like 45 or something and see if that helps any of the issues. Assuming it's possible and doesn't screw things up worse.

In the mean time, fixing it is as simple as going in the Radeon control panel and turning off freesync. And then turning it back on when I go to play a game. And then quitting the game and actually turning it back on, because I forgot. And that gets old fast.

Even if the flickering isn't game breaking, is it a deal breaker? I don't mind sinking this kind of money into a monitor with no glaring faults. The kind that I expect to keep for several years. But this is not the kind of problem I want to ignore and try to live with. Even if it is, strictly speaking, tolerable.

Before moving on, I noticed one other thing. Watching the same video side by side with my MG279Q, the MG279Q is noticeably smoother. It's not a huge difference, but it's definitely there. I'm not sure if it's because the MG279Q has that little extra motion blur, if freesync is actually doing its job in that situation, or the 90hz refresh rate just syncs up better (multiple of 30) than 100hz, or all of the above. Or if there's any other factors I don't realize. I still enjoy video on the CF791 very well. In some cases, the color and contrast are really the only things I notice. Not to mention, 21:9 content going full screen is a big deal!

Finally, that 1500R curve. It's going to be another personal preference I guess, but I think it's way too extreme. I had really bad eye fatigue for the first few days. I felt it had to do mostly with the curve distorting the image. Now that I'm used it, I don't get fatigued anymore. In game, if I'm sitting pretty close, I don't really notice. Otherwise, if I'm just sitting on the desktop, looking at browser windows, or watching a movie from father back, there's distortion. In all these scenarios, the image is plainly bent around the inside of the curve. It does not trick itself into looking flat, like it's supposed to. At all. I think that 'mitigating the color shift' is the only excuse for this. Using a tape measure, I feel the optimal distance from the curve is only around 20 inches. I think somewhere in the 28-32 range would be more desirable.I rather err on the side of too flat, I think.

Other thoughts:

In the end, if there weren't any other options to consider, I'd recommend the CF791 hands down. 21:9 friggin rules! And in the middle of a game, the wide ratio and eye popping image are enough to make me forget its shortcomings. As much as I groan about it, the color shift still isn't the end of the world. When I'm sitting dead center, nose to the glass, fully immersed, anything else in the world is the last thing on my mind, like it should be. At least until the action slows down and I find myself scanning a dark room for the next threat, loot, hidden switch, or whatever..
Basically, it's the monitor equivalent to a sports car. You love it to death on the weekends, but it grinds you down a little on the daily commute. Or that hot girl you're sure you're in love with for the first two weeks until you realize she's a head case.. I've had both in the past and with age comes, well, being a little more boring.. Which brings me back to the beginning of this absurdly long "pre-review."

I said at the beginning that I also broke down and ordered an XR341CK. I could give up just a little vibrancy and the last few hz for wide viewing angles and a shallower curve. As far as I know, this acer is the only other serious contender in the freesync market for 21:9. If it has similar overall performance to my MG279Q, especially if it's a little sharper, I think I'll be happier in the long run. I know it's "only" 75hz, but if I get one that hits at least 85hz, I think I'll be set. 90hz would be perfect. I know people have had a lot QC issues with these, especially the earlier runs. Hopefully by now, I'll get a really good one. Either way, at least one of these will go back. Hopefully I won't get hit with a big restocking fee.

I know there's a couple really compelling g-sync screens. I guess I'm a bit loyal to the Radeon brand. I've been using them since the first one came out. I have high hopes for Vega, but realistic expectations. Either way, I'm tepid to the idea of paying $1-200 extra for basically the same screen, just to be stuck with Nvidia instead, who, technically could decide to support freesync at some point in the future.

I expect to receive my XR341CK sometime this week and at least spend the weekend with it before formally posting my thoughts and comparisons. In the mean time, feel free to post questions.
 

Xorak

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Jun 7, 2013
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So, good news and bad news. I got my XR341CK today. I can report that it looks impressive sitting on my desk. I was wearing of the two tone lower bezel, but in low light it basically just looks black. What else? Oh! I like the handle on the stand, but the balance is very forward, so I wind up grabbing the bottom of the screen or one of the legs, which is awkward.

In terms of image quality, the CF791 is still in the lead. Largely because, I can turn it on! The ACER didn't come with its power supply! I did some research to see if the Samsung brick would have suitable output. I think it does, but the plug is a different size.. At least my initial impression of the XR341CK's black levels is very favorable. I haven't seen any bleed at the edges or corners yet either.

In all seriousness, this is a real drag. It's already Thursday night and I really wanted to try the thing out over the weekend. I'm running out of time on my 30 day return period.
 

Xorak

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Jun 7, 2013
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Another quick update. I called around from work yesterday morning. Newegg didn't have another new XR341CK to send me. They did have an open box model for less, which is cool. I talked them into sending me that one, giving me the fastest shipping for free and putting a note on my file that at least one of them will be getting returned later, no questions asked. Unfortunately, because of the timing, I still won't get the replacement until Monday. I have Sundays and Mondays off, so I should get at least a few hours of quality time in. And I'll have two samples of the screen to try out!

I tried acer customer service too, between calls to Newegg. Without a product s/n handy, acer's answering system simply wouldn't allow me to talk to anyone. Period. Props to Newegg. Acer really isn't making a positive impression so far.

On the CF791, I was apparently able to expand the freesync range down to 40hz with a custom resolution tool. I haven't spent much time gaming that way yet, but I can confirm freesync is working and it hasn't caused any problems.

As for the flickering in game, I spent 15 or 20 minutes in Fallout 4 trying to get it to flicker. Originally, it was fairly easy to get it flickering at ~48fps if I was trying to make it happen. This time around, I tried and tried and finally got it to start flickering at ~43fps once. Then I couldn't get it to do it again. I loaded up The Division and Witcher 3 for a few minutes each and had no problems. For the time being, I would consider my flickering in games problem solved!

Full screen video on Netflix or YouTube etc. still flickers, albeit not badly. It's still not acceptable and I need to turn off freesync in that situation. On the other hand, I haven't had full screen video black out the screen and reset the display port connection yet. That at least is a big improvement.
 

Xorak

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Jun 7, 2013
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Not sure anyone is actually following this. If you are, sorry I dropped off so long. Real life and all that.

Right off the bat, I've returned the CF791 and kept the XR341CK. It was a brutal decision. I don't regret my choice exactly, but I'm disappointed because the CF791 came so close to greatness.

Next, disregard most of the previous post. It'd been trying to update my video drivers and I thought freesync was working on the CF791, but it wasn't. It was just the 100hz refresh rate and lack of refresh indicator on the OSD that can make it hard to tell sometimes. Long story short, between 3 freesync screens and two graphics cards, I haven't found a permutation where any post ReLive driver version has freesync working. This is an inconceivable problem at this point, but also a topic for another thread.

Given my recent difficulties with freesync in general, the way the monitor handels them is very important. The Acer and Asus monitors either work with freesync, or they don't. They don't throw a temper tantrum when things aren't right. That's our job as the human and the consumer! Both also have methods to monitor freesync'a activity without any guess work, which makes trouble shooting easier. The CF791 on the other hand, will blank out and reset and sometimes not come back until I exit the application blind, or just restart the computer.

If Samsung had implemented freesync in the CF791 more successfully, I would have kept it. Even if the occasional flicker around the minimum refresh rate were present, but the only odd quirk, I would tolerate it. I was able to set my sample down to a 40hz minimum, further mitigating the effect, but not eliminating it.

If the viewing angles had been a little wider and/or the dark color crush had been a little less, I probably would have kept it in spite of the flakey freesync. Addressing either of those properties would have helped the other. And if they were addressed, the image quality would simply be too irresistible to give up unless the monitor flat out didn't work.

Actually, the only downside I noticed to the CF791'a color is that moderate tones aren't quite as smooth or natural as they are on either of my IPS screens. I think the wide color space and high contrast might both contribute to revealing any flaw or banding in the original content. Also, because red is so strong and si, well, red on this monitor, certain tones turn more red than they're probably supposed to. It's most noticeable on skin tones. The reds are so red that any other red looks like a deep shade of orange. I don't think I've seen an Illuminated red that's this pure red anywhere else. Once actually been keeping my eyes out on real life, seeing if anything actually ever looks like that and I don't think I've seen it. Even modern cars' led brake lights aren't as pure a red.

I'm starting to gush again.. I think an instrumented calibration might really take this thing to the next level though. If only they'd gotten everything else right..

When I combined all the deficiencies, it was just too much to deal with. And I still regret my choice at times. The color and contrast really ruined me. This has been a nice glimpse into the future. When features like HDR, OLED or Electro Luminescent Quantum Dot start hitting the market, it's going to be very, very exciting.

In the end, I probably would have been happiest if it's just gotten the XR341CK first and never seen the CF791. The Acer is an amazing monitor that I wound up getting a sweet deal on.. And now, can't fully appreciate for what it is.

Edit: One more impression I meant to update was my feelings about the extreme curve. It actually grew on me a bit. It's very noticeable if not exactly bothersome for desktop and web etc. usage. It's not bad for movies and video, but I think I prefer the shallower curve of the XR341CK in these instances.

In a first (or third) person game, the curve makes a lot of sense. It makes it a lot easier to take in the whole screen and it also reduces distortion at the edges. On the acer, I feel that as I move forward, objects appear to accelerate very quickly as they reach the extreme edge, but the CF791 mitigates that a bit.

On the other hand, top down games like an RTS look pretty weird on the CF791. Flat ground always looks like a big valley.

The CF791 has a 1500R curve and the XR341CK apparently has a 3800R curve. It's tempting to say that something in the 1800R to 2300R range might be best, but I'd have to try it to know. The acer is just enough to basically look flat when you sit back a bit. Going just a little more than that may bring all the disadvantages of a noticeable curve, without all the benefits of a more extreme curve. It's hard to say. I'm pretty sure I'd like to try something at least like 1800R though.
 

Rooooney87

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Mar 30, 2017
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Hey Xorak,
thanks for sharing your experiences with that 2 screens. I want to buy a 21:9 screen with the same features you posted here as well. After waiting for a year that the price point for monitors like this will decrease I giving up the hope and taking some more money in the hand to buy one.

The Samsung and Asus VA panels tooking my attention. Can you give some "long time experience" with the acer? Normally I want to go with the VA panel but if you say the acer is pretty the same in kind of image quality I would rethink this decission =)

And also the Input lag would be interesting for me.

In kind of games: I play a lot of Racing Games (advatange for the curve) but also playing a lot of League of Legends (seams to be a negative point isn't it?)

regards
Rooooney