06-11-2009 09:49 AM - edited 06-11-2009 01:28 PM
I've been doing some research on the W500. I understand that the only way to make the laptop output DVI is to use the docking station.
I also understand that the docking station has one VGA output and one DVI output, and you can utilize both of these to drive one VGA and one DVI monitor.
My question is, is it possible to drive two external DVI monitors by using a device such as a DVI splitter box connected to the docking station?
An example of this device can be found here: http://www.matrox.com/graphics/en/products/gxm/dh2go/
This device advertises as being able to support the highest resolution (1920x1200) so I suppose the quality of using one of these would be quite good.
Thanks for your help,
06-11-2009 04:55 PM
06-11-2009 07:01 PM
Thanks for the response.
Since posting that, I've done a bit more research and come to the realization that there's no "true" way to use two DVI monitors at a resolution of 1920x1200 each using the W500 laptop.
There are several options I've come across, however:
1. What you mentioned, is that you can use a USB to DVI converter cable. This will work, however quality will suffer and picture quality will not be as good as using a pure DVI output. And as you also mentioned, USB to DVI converter cables that support 1920x1200 are hard to come by.
2. Another option is the display port to DVI converter cable for one monitor, and the dock for the second. The drawback to this, which is a major one, is that you cannot use both monitors at the same time using this option.
3. A third option is to get what I was talking about, the DualHead2Go Digital, which is a single-VGA to multiple-DVI converter box. This essentially "tricks" your computer into thinking there is only one external VGA monitor. This works, and allows you to use two external monitors along with your laptop screen. However, there are several drawbacks. One, it's a bit pricey. Second, a VGA to DVI converter is essentially an ADC (analog to digital converter), which as I know from my field in electrical engineering, inherently is not perfect. You can only sample so many times per second. What this means is that quality will suffer opposed to using a pure DVI output. Third, this is only a good option if you have two of the exact same sized monitors using the exact same resolution. If you were using two different sized monitors, one using 1920x1200 and the other using 1600x1200 for example, it will be tricky to get the DualHead2Go to adjust your screen settings to be adequate.
4. A fourth option, and the only legitamate one in my opinion, is to get the Advanced Dock, which has one slot for a miniature PCI Express card. A second video card with a DVI out can be purchased and put into the PCI Express slot, allowing you to feed the second DVI monitor directly into the video card. This will work with no problems. There is one major drawback. The advanced dock is very pricey, at over $300, and you also need to purchase a second video card which is even more money. From what I've seen on the 'net, this has only been tried once, but it seems to me like it should work if one has the resources available.
I guess with time VGA will be phased out, but for now we're stuck with only one DVI and one VGA. What I've decided to do is use an existing 19" VGA monitor as my secondary monitor, and buy a nice big 24 inch Dell Ultrasharp 2408WFP for my primary DVI monitor. The Ultrasharp will be at 1920x1200 and my secondary VGA will be at 1600x1200. I'll use the Ultrasharp for CAD, Photoshop, and all the good stuff, and the VGA will be for e-mail and browsing the web. Not really a huge deal to me, but it would have been nice to be able to use two digital monitors without going through a hassle.
It took me a while to research, so hopefully some people benefit from this post.
06-12-2009 03:49 PM
The recently released lenovo usb adapter uses the new DisplayLink dl-195 chipset which has better performance and supports
the 1920x1200 resolution. About $129, way cheaper than the advanced dock plus graphics card.
You can add up to three of these to a system with switchable graphics (6 on other systems)
Fot the first monitor you should use the display ouput of your laptop (or dock). For my w500 system I use the dvi out from the dock and a usb adapter. If your system has a display port you can also buy a $20 cable to connect that to dvi.
06-14-2009 12:56 PM
jeblis, thank you for that information. I hadn't come across that previously.
My only question is, can you use two Digital monitors simultaneously with one monitor connected to DVI via port, and the other connected through USB with this cable?
From what I've gathered, using the Display port only allows you to connect two DVI monitors, but you can only use one at a time.
If this cable allows you to use two DVI monitors simultaneously, that's very good news.
06-14-2009 01:13 PM
Yes. I usel two external digital monitors, plus the laptop display on my w500.
Fot the first external monitor I use the DVI output of my dock, but you can also use a display port cable/adapter (~$20) to get DVI out of the w500. Older models w/o the display port must use a dock for digital output.
For the second external monitor I use a usb video card like the lenovo one. (~$129)
06-14-2009 05:26 PM
Thanks for that information. I'm glad it actually is possible to use dual DVI with the W500.
Since you're using a USB to DVI cable, how do you find the quality? Is there any significant difference from using the DVI output from the dock (such as lag, image quality, etc.)? Or does it give the quality of plugging in a DVI monitor straight from the dock itself.
06-14-2009 09:15 PM
The image quality is identical to the DVI from the laptop/dock. What you may notice is that the performance of the USB display
is not as fast as the laptop/dock dvi. Don't expect to be able to play high quality video or games on that monitor since the USB port has limited bandwidth. For 2d applications it works great.
I'm using the older model and I don't really notice any performance issues since I use it for web/text display. The new model is supposed to have two rendering engines to speed up performance.