Yes. I observed that too. Mostly (I think all of the cases) are that the screens blank when you have a new USB device plugged in (e.g. thumb drives, mouse, etc.). And sometimes it even triggers the repositioning of monitor orders or the size (e.g. 1920x1080 became a lower-res size, something like that). Maybe it's not supposed to but it does occur. The direct video card is the best solution. In my case, I had maxed out on all my PCIe X16 slots on each computer, and I am not willing to spend $$$ to get quads. For me it is okay because during the trading session, I don't touch anything. Occasionally in after hours I plug in thumb drives or hard drives to transfer data. I use network file transfers whenever I can.
Mine were usb 3.0 versions, so maybe this was a factor, but it was doing it to me at random. I rarely, if ever, plug a usb device in, so I know it wasn't related to that. It could have been the USB 3.0 hub causing the problem, but I sort of doubt it. I had to get a 4 port hub to run them. I updated my usb 3.0 drivers to the latest, and also installed the latest motherboard bios, neither fixed it. My quad cards were fairly reasonable, at $249 shipped each.
Sometimes I felt that the screens blank out at random too, but it was me stepping on the USB cable or something. It could also be a loose USB contact. It can also be the internal wires from the motherboard to the USB plug (if in the front). And of course it can be really random, I don't know.
I plugged my hub in on the back, so it wasn't loose cables I don't think. I think it could be just usb technology itself isn't reliable, when transmitting a lot of data. I've seen random disconnects on other things too in the past (on other computers), like external hard drives. This computer only has the keyboard and mouse running on usb. And those are in the 2.0 slots in the back, not usb 3.0. I concluded the DisplayLink adapters weren't a safe route, mainly due to the fact that it doesn't just blank the screens on usb, but all the screens while it's reinitializing. With six displays it would take about 4 minutes to initialize, so it wasn't a momentary glitch.
I have two FirePro 2460 cards (able to run up to 8 monitors). I currently run six 24" 1920x1200 screens, using mini display port connections. Works just fine, and was the most cost effective (I don't do any gaming). NVS cards are also good.
In their literature it mentions something about the "crossfire performance benefit" from combining the onboard video capability with the video card... "onto one monitor"... as would be expected from crossfire. Likely the disabling of the crossfireX feature is what enabled the 4-monitor display.
Yeah, crossfire is combining the two cards to act as one. If you enable it, you will get the functions of one card. Least, that's how it was when I tried a crossfire setup for gaming, it disabled the second card completely to use it for extra ram and gpu's.
I did notice something that I think explains why deselecting Crossfirex worked. When the discrete video card was installed, at that point its was designated as the "primary" video card and the only one displaying, according to the ati catalyst software. It recognized the "linked"graphics hardware of the internal onboard graphics as secondary -even though the onboard graphics is superior technically to the hd3450 card. Now after deselecting the crossfirex, I see that the order is now reversed, it now sees my onboard graphics as the primary and the video card as linked/secondary - I did not change this in the bios, it did this automatically. I would bet that if I go back into ati catalyst and select to enable crossfire (hybrid) now that the correct graphics is in the "primary" position, I bet it would then combine to act improve graphics performance, acting as 1 video card with 4 monitors output. But I have it working as is and dont need the performance boost so I dont want to mess with it ) - I think for my purpose the "surroundview" of the linked combo is all I need.
Video demands on a trading rig... regardless of how many monitors you run, are EXTREMELY low. Video "performance" doesn't matter in the slightest. My first multi-mon trading rig had video cards with 2MB of VRAM and Passmark scores in single digits.. they worked the same as ones today.
We are running NVS 420 cards these days. They are a little unique and funky (different adapter and plug) but they are as reliable as the passive LP 290/295 cards so far. I wish they didn't have a fan. (wish they were passive) $80-$100 used all day long on fleBay