I did see a higher end card, the Sapphire Radeon HD6670 Ultimate 1GB- fanless. Same 400w power supply requirements as the HD 6450 Flex, but much higher performance. That would probably be the one to get, for like $30 more, the question is would it fit in the case? I know the 5000 series Radeons did but they seemed more long, this seems more boxy.

And- are you sure that all 3 monitors will run at their max resolutions? I read that with Eyefinity the monitors must all be the same resolution, but I'm guessing "Eyefinity" in this case means gaming and not extended desktop. I just know I already have a card I thought would support Eyefinity 3 displays but it, being the low-end card, didn't. Don't want to get fooled again.

Normally, you only find low-end cards that are passively cooled so the HD 6450 Flex is a good choice for what you need.  It does have better performance over the HD 5450 and only uses approximately 10 more watts in reality. The HD 6450 uses approximately 30 watts and the HD 5450 uses 20.  I have the HD 6450 running just fine on a Dell 275 watt power supply.   Your power supply could handle a much higher-end card, but they would all have fan cooling.  

It has a large heatsink, but it should fit okay.  The card is 7" long and 5.5" high.  It's a dual slot card so it will take up two slot covers in the back.  

I'm sure you have read the question here:

I’ve heard all of the monitors need to be the same resolution for AMD Eyefinity technology to work. Is that true?

It’s partially true. AMD Eyefinity technology is a brand name that actually describes three distinct functions:

1. Hardware support for three or more monitors attached to a single graphics card.
2. Software support to independently configure and run each of those displays.
3. And software support to combine the resolutions of all of those displays into one big resolution.

At a basic level, many users like AMD Eyefinity technology for the first reason: connecting more than two displays is no longer a challenge as it has been in the past. And whether you run Linux, Microsoft® Windows® or Mac OS®, each operating system works seamlessly with AMD’s hardware/software to connect and configure multiple displays.

Assuming for a moment that you never perform any additional configuration once the monitors are connected, these displays are running in what’s called “extended mode.” Monitors do not have to be the same size or resolution in this mode, and you should feel free to rearrange your games and applications across the extended displays as you see fit.

The primary drawback to extended displays is that a game or video cannot readily be maximized to take advantage of all the displays at the same time, which is where AMD Eyefinity technology’s SLS mode steps in.

Single Large Surface (SLS) mode is activated when you create an AMD Eyefinity technology display group in the AMD Catalyst™ Control Center. SLS mode combines the resolutions of all the connected displays, and then essentially “tricks” the operating system into believing that there is one display with that large combined resolution. 

While SLS mode does not require all monitors to be of the same resolution, SLS mode will force each monitor to match the smallest resolution on any of the displays you’re combining. For example, a 1680x1050 monitor paired with two 1920x1200 monitors will force the 1920x1200 monitors to 1680x1050 before they’re combined for a final SLS resolution of 5040x1050. For this reason, we do strongly encourage all monitors to have, at the very least, the same resolution. Provided you meet this technical requirement, we think you’ll find the effect of SLS to be absolutely breathtaking.

Seeing is believing, though, and this interactive demo shows just how much you’re missing in the games we’ve validated if you’re playing on just one monitor. Even many of the games we haven’t validated also look great with AMD Eyefinity technology! 

The same demo also shows how users can be more productive in a professional environment with an AMD Eyefinity technology on an AMD FirePro™ professional graphics solution.

But AMD Eyefinity technology isn’t just about games. The prestigious market research firm, IDC, has shown (PDF) that workers are more productive when equipped with a multi-display solution like AMD Eyefinity technology.  Even with SLS mode enabled, each display can be treated like an independent monitor with the AMD HydraVision™ software.

So, whether you choose SLS or extended displays, the versatility of AMD Eyefinity technology virtually ensures that there will be a solution to help you work smarter and game harder.

Thanks. I'll probably go with the Sapphire Radeon HD6670 then, once I have time to get a side by side comparison with the 6450 on power consumption. I'll leave the thread open for a while to see if anyone else has any ideas.

The HD 6670 will use 60 watts while the HD 6450 uses 30 watts.  The HD 6670 runs on Dell 300 watt power supplies without any problems.  

If performance is an issue, the 7750 is a better choice. Its power consumption is similar to that of the 6670, but its performance is much superior and is roughly equal to the mid-ranged gaming card of 2010, the 5770.

And this is the latest and greatest passive cooled card? Nothing else in the pipeline to be released soon?

In a video review I saw of the 7750, the only concern expressed was the amount of heat dispersed in the case, so you're supposed to make sure there's good airflow. Which the XPS 7100 has, at least used to have when I bought it though the power supply is getting older. Either that or the hard drive has been getting whinier.

I spent a good hour and a half getting pingponged around by Dell last night just trying to tell them that yes, I received the cable and no, the new DVI-D still doesn't screw into the GPU's DVI-I port any better than the the last one (though the single link DVI cable screws in fine. Anyone have any idea why that would be?) Transferred 6 times, put on hold about 5-10 minutes each time. But I'm not sure what I'd be asking them to do, anyway, I'll be narrowing down my choice on the GPU, getting that sent, then installed, then as long it works, great, otherwise if there's a problem with the monitor hopefully it'll be within the return time frame.

This will work, right?

Computer: Dell 7100XPS with AMD 1055t (2.8Ghz) processor

GPU: Sapphire Radeon HD6670 Ultimate 1GB DDR5 DVI/HDMI/DisplayPort PCI-Express Video Card 100326UL or

          Sapphire Radeon Ultimate HD 7750 1GB DDR5 HDMI/DVI-I/DP PCI-Express Graphics Card 11202-03-40G

Montors: Dell U2713HM-IPS-LED CVN85 27-Inch Screen LED-lit Monitor, connected with Display Port (2560 x 1440

                resolution)

                Dell UltraSharp U2412M 24" LED LCD Monitor - 16:10 - 8 ms, connected with HDMI- (1920 x 1200

                resolution)

                ViewSonic VX2025WM 20-inch Widescreen LCD Monitor, connected with DIV-D (1680 x 1050 resolution)

When you said XPS 7100, I thought you were referring to me! Yes, I have an XPS 7100 chassis retrofitted with an Asus P67 mainboard, Core i5 CPU, HIS 5670 video card (with whisper-quiet Arctic Cooling Accelero L2 cooler) and Seasonic 520-watt power supply with thermostatically-controlled fan. Of all the machines both OEM and homebuilt I've had, this one is probably the quietest.

I think the 7750 has minimal heat generation, which is why there is a dimunitive low profile version from Sapphire that works in tiny mini-ITX cases with 220-watt power supplies. The HIS 7750 features an Arctic Cooling Accelero L2 fan that is virtually inaudible, and from personal experience with the same cooler in an XPS 7100, I would heartily recommend it.

The 6670 is cheaper, but it uses more power (and hence generates more heat), even while being less capable.

Thank you for your advice, I'm probably going to follow it. My 7100 was a refurbished, and just like my refurbished Dimension E521 before it there's always been something rattling in there, which goes away if I press on it, but it's been quiet lately other than the power supply fan whine (when I say "whine" I mean a high pitched background sound, not something in its death throes or anything.) But still noticeable. You bring up a good point about the power supply, they tend to go after 4-5 years and can take things out with them. SO- maybe I should get:

Computer: Dell 7100XPS with AMD 1055t (2.8Ghz) processor

GPU: HIS iCooler H775F1GD Radeon HD 7750 1GB 128-bit GDDR5 PCI Express 3.0 x16 HDCP Ready Video Card

Power Supply: SeaSonic S12II 520 Bronze 520W ATX12V V2.3 / EPS 12V V2.91 80 PLUS BRONZE Certified Active PFC

                          Power Supply

Montors: Dell U2713HM-IPS-LED CVN85 27-Inch Screen LED-lit Monitor, connected with Display Port (2560 x 1440

               resolution)

               Dell UltraSharp U2412M 24" LED LCD Monitor - 16:10 - 8 ms, connected with HDMI- (1920 x 1200

               resolution)

               ViewSonic VX2025WM 20-inch Widescreen LCD Monitor, connected with DIV-D (1680 x 1050 resolution)

Spend $35 or so more in total but get the less expensive card while possibly eliminating some of the current noise, assuming it's not the hard drive.

Actually, the power supply model is just a guess, I don't know which one you have or if there's a better one now.

Er- nevermind, no.

Would the

HIS iCooler H775FS2G Radeon HD 7750 2GB 128-bit DDR3 PCI Express 3.0 x16 HDCP Ready Video Card

be an even better choice?

Bought it! (The HIS iCooler H775F1GD Radeon HD 7750 1GB.) (Rubs hands together.)