^ Yes, the DP port on my W700 has access to the full 4x(1920x1200) resolution of the internal video card. However, half of that is being used by the DVI port. Therefore the max stream coming out of the DP port is 2x(1920x1200). I run that into the Matrox DualHead2Go DP splitter and it drives two separate 1920x1200 monitors. Works just fine.
Now that I think about it, the above must be why things wouldn't work when I added an additional DVI link to the VP2290(directly from the laptop DVI port; no splitter involved) on top of the existing 3840x2400 signal coming out of the DP port. The video card was already maxed out via the DP port and therefore couldn't do much with the extra DVI path. I'm not much of a video guy, but have gotten some things to work via grunt labor/trial and error.
Intriguing idea about splitting up the DP stream several times to jack up the Hz on the VP2290. I suspect your specific question about running TWO 1920x1200 streams into the VP2290 from the DP splitter would work OK. However, THEORETICALLY, even this -might- be possible:
Laptop DP port connects to a Matrox DP splitter. Out of the splitter comes two DVI paths, each of which -might- have a Matrox DVI splitter hooked up to it. Coming out of -each- DVI splitter are TWO DVI paths, so that would total FOUR DVI paths coming out of this mess. You could then hook all four of these DVI paths up to the VP2290 and see whether you'd blow up the neighborhood or just -maybe- have sumpin' that would work. This crappy editor won't allow me to chart out the config visually, but that's the gist of it. The W700 video card can do full speed video to four DVI streams(I'm already doing that), and by splitting it off four ways out of the DP port, it -might- just work. What's undetermined here is whether the 13Hz limitation you mentioned is bottlenecked -only- by the one path out of the VP2290 or whether there's some sort of bandwidth/speed limitation inherent with the DP port on the laptop itself. Since I'm already doing full speed video out of my DP port for 2x(1920x1200), I do wonder if the DP port can handle the full 4x(1920x1200) path at full speed. "Inquiring minds GOTS to KNOWED."
Kinda of a convoluted explanation, but it's late and I'm zonked out, ready for bedtime...
I have the hardware to do the above, but it's tied up on my production system and I don't want to move it, try the above and then have potential problems hooking it back up to the production box. Running a mix of two DVI and one DP splitters is not only unsupported, it's very flaky and touchy when making changes. I leave it as-is to minimize problems. If I can do the below listed ViDock 6 port card stuff, that will free up the splitters and I'll give it a try. Gonna be at least another few days to a couple of weeks before I'll know whether the ViDock 6 port config will work.
A possibly simpler route to the above might be to take what I already have, which is a splitter off the DVI-D port and a splitter off the DP port and just run the four(total) paths directly into the VP2290 and see what happens. I don't know if it would show up on the VP2290 as four separate adjacent 1920x1200 regions, which causes problems trying to get an app to run in full screen mode, or whether it'd all work great and just be one huge 3840x2400 screen. I may try that, too, if I get my new video setup working. Point is, there may be a way to cram the VP2290 bandwidth into the W700(or a W510/W520) via some combo of splitters. RonS has posted some results on multi-monitor support via W510/W520, and if I remember correctly, Lenovo got cheap and made the DVI ports on those DVI-I, which will NOT drive two 1920x1200 video streams. If so, your best bet would be to drive it all out of the DP port + a bunch of splitters. RonS might chime in on this one, as he's THE video guy for multi-monitor support on Thinkpads...
DualHead2Go DP splitters seem to run about $200-250 on ebay and the TripleHead2Go Digital DVI splitters are ~$150-ish, so you can see this isn't dirt cheap to get going. Personally, I like the idea of driving it all out of the DP port, as you avoid the DVI-I issue on the W510/W520 laptops, and in addition, I suspect you'd have better luck getting it all to work as one large 3840x2400 desktop. If you decide to do something like this, run your config by the board here, as there are -many- different versions of the Matrox DVI splitters, and the ONLY ONE you want for DVI stuff is the 3-way digital version.
On the W700, the video card itself can drive four 1920x1200 monitor streams, so the challenge is how to get all of that in/out of the laptop via one DVI-D port and one DP port. That's why I ended up using Matrox splitters; one on the DVI path and the other on the DP path. Each splitter routes it's 2x(1920x1200) stream to two separate monitors, resulting in a total of four 1920x1200 monitor displays. And, it pretty much works(mostly). That said, I'm in the process of trying to figure out & install a 6 port ATI Radeon Infinity 6 card via a tinkered with ViDock box, so that I can dump the Matrox splitters, cuz they're somewhat of a pain in the butt. This stuff wasn't designed to work in this fashion and it occasionally craps out...usually when I don't want it to. But, over time I've figured out most of the bugs and can make it work.
Eventually, I'll drive six monitors via the ViDock(I hope) and the other two via the two normal DVI & DP ports in the back of the W700.
And, as soon as I get some more $bucks$, I'm either gonna upgrade to a W520 and run the ViDock+DVI+DP(or is it HDMI?) combo, or I'll get a mini tower and go with a desktop type config. With a tower, it's easy to install two identical six port video cards(total of twelve monitors) and also get a screaming i7-3960X chip, which is ~2x the i7-2960XM chip's power in the highest end W520. Or hell, I may just buy both and sort it all out
Btw, if you are starting from scratch on trying to get a VP2290 monitor going, I recommend you try one of the current ViDock boxes with a four port video card that'll drive 3840x2400 or greater. In the past, the problem w/VP2290 was -very- expensive video cards, in addition to figuring out how to make it work from a laptop. These days, many inexpensive video cards should support the VP2290 and the ViDock box is $200-300, so one might do this a lot easier and somewhat cheaper by skipping all of the splitter stuff. Since all of the ViDock boxes interface via the ExpressCard slot, you bypass the DVI/DP ports altogether and any bandwidth issues there. The only reason I got involved with all of these Matrox splitters was because there was no other affordable solution when I was setting this up a couple of years ago. These days, there are better/easier/cheaper approaches via ViDock+video cards. Up to you...have fun...