2001FP comes with a 24 pin DVI-D cable... or does it?...

Don't sweat it. It will work fine!

I think you're right... it's just something I identified as a possible contributing factor for the problems I was initially having with the 2001FP and my ATI Radeon 9600 Pro video card.... screen would sometimes flash on and off every few seconds at 1600x1200 unless i checked ATI's option to "reduce DVI frequency for higher resolution monitors".  It got me thinking that that problem could be related to trying to push too much data down a single link DVI channel.

That's when I noticed the DVI-D cable that Dell ships was an 18 pin single link cable, rather than the 24 pin cable mentioned in their spec (which would be a dual link).  Obviously this is a moot point if the display's (or grahics card's) DVI interface only supports a single link.  This confusion isn't helped by the web being full of cable vendors eager to sell you a "quality" dual link capable DVI cable upgrade... but who make - for obvious reasons - no mention of the fact that those extra/expensive 6 pins may go unused.  A little more research, and I believe that the situation is this:

A single DVI link can support data rates of up to 165MHz, or 165 million pixel changes per second.  Taking the capabilites of the 2001FP would seem to yield: 1600x1200x60Hz as the number of pixels that would change per second (pixels on screen multiplied by the number of times they change per second) = 115.2MHz, which is less than the maximum data rate capabilities of the link.  So, the demands of the monitor shouldn't require a second link.

There's a good reference available at http://www.pctechguide.com/07pan2.htm (see the DVI section).

It seems the 165MHz limit is there because of the properties of copper as a conductor: the "Copper Barrier".

Still, it would be interesting to find out if dual link operation is supported by the monitor, and our graphics cards.  If it is, sharing the load over both links seems like a nice idea... even if it's really unrequired.  I suspect it's not supported, because it's not necessary at the max resolution/refresh capabilities of this monitor.

But... this does generate a new question: If only 115.2MHz of data is expected over the single link for this display, and the DVI link is capable of dealing with 165MHz of data being clocked down it, why does my ATI card need to "reduce the DVI frequency" in order to reliably talk with the 2001FP?  Is the monitor unable to keep up because they're sending it faster than they should, are ATI doing nothing wrong - and the monitor can't keep up, are ATI currently unable to send good/clean data that's within spec, etc?

Message Edited by nigelcc on 03-31-2004 09:45 PM

##  IMPORTANT  -- DVI SOLUTION?  ##

I may have found a solution to the DVI problems so many have reported lately with some Dell monitors.  Bear with me, I'm getting to it...

• my specs --
• Dell 2001FP monitor, Rev A00, manufacture date Jan 2004/Feb 2004  (I've tested two so far)
• BFG GeForceFX-5900 video card  (max resolution = 2048x1536)
• Windows98SE
• ECS K7S5A motherboard
• Athlon XP-1800+
• 512MB Crucial DDR 266

I recently bought a 2001FP flat panel monitor from Dell - Home and Home Office to go with my new GeforceFX-5900 video card.  Analog connection works fine, but within the first two days using the DVI connection, I experienced three of the common problems noted on these forums --

1- No screen output during bootup (almost always, though it did work properly a couple of times)

2- No output in resolutions higher than 1152 x 864

3- Monitor gets stuck in Power Saving mode

The DOS malfunction led me to think this was not a software issue. I tried a replacement monitor from Dell... no improvement. From this and other forums, I saw that these problems are occurring with various models and makes of both ATI and Nvidia video cards -- not a particular type of video card, then, though my card could possibly be defective. After fruitlessly spending days browsing forums and testing with various monitor setups, I noticed that my DVI cable had only 18 pins, although it is described in the monitor specs as a 24 pin cable.

• 18-pin cable =  low-bandwidth single-link DVI connection
• 24-pin cable = high-bandwidth dual-link DVI connection.

For more information on DVI cables see these web pages --

 http://www.datapro.net/techinfo/dvi_info.html

 http://www.ramelectronics.net/html/DVI_monitor_cables.html

I thought perhaps the monitor had shipped with the wrong cable, so I called Dell Tech Support. Trying to talk to the script monkeys in Bangalore (or wherever) was beyond frustrating -- it's obvious that none of them have ever even seen this monitor -- but after repeated calls, I did find out what they are looking at when they refuse to discuss this with me. See this link to the "Specifications" page of the not very informative User's Guide for the 2001FP --

<ADMIN NOTE: Broken link has been removed from this post by Dell>

Scroll down and you will find a pin-out diagram of the "24 Pin Digital DVI-D Connector". Notice that it is actually a picture of an 18-pin cable, so the cable shipped is the one pictured, but is it the right cable? In theory, a single-link cable should support bandwidth up to 1600x1200.  I decided to test the 2001FP with the included DVI cable on a neighbor's Radeon 8500 based machine. During three days of use on that machine, the monitor worked flawlessly. So... the problem must be in my video card, right? But here's the thing...

I wanted to cover all my bases, so I ran down to the local Best Buy and picked up a 24-pin dual-link cable.  And for the week or so since I've been using this cable, my monitor has worked flawlessly with my GeForceFX machine on the DVI connection!! No trace of the previous problems. When I again connect the monitor using the Dell 18-pin cable, however, I immediately see the same malfunctions as before.

So -- is this happening because the new cable is dual-link, or is it just a higher quality cable than the one Dell supplies?

If anybody out there is able to experiment with some other cables, I'd like to hear about it. Right now I am waiting to receive a replacement for my video card, which might give me some more data, but my 30 days is almost up and I am seriously unhappy with Dell's idea of customer support.  I may not even keep the monitor just for that reason. And, by the way, I don't regard having to spend an extra $50 for a new cable as a satisfactory solution.

The $49.99 dual-link cable I purchased from Best Buy is this one --

Belkin Pro Series PC Compatible - 10 ft. Digital Video Dual Link Cable, model # F2E4141-10-DD

Message Edited by PaintedJaguar on 04-02-2004 05:36 PM

Here is some tech info that I found on another thread:

Dell summary of the DVI spec - http://www.dell.com/downloads/global/vectors/dvi.pdf

Complete tech info on the DVI spec - http://www.ddwg.org/data/dvi_10.pdf

Also, check out the www.rage3d.com forums, if you search for DVI and LCD you'll find a long standing thread that covers these symptoms.  There seems to be an ATI employee there who's been responding, and it appears they're working to find the cause and a fix in the drivers.  No news yet on what the root cause is, but a few others also mentioned that enabling the "reduce DVI frequency" option provided some relief for them also (same symptoms... blinking screen and no display until windows starts for some).

http://www.msicomputer.com/product/detail_spec/product_detail.asp?model=FX5900-VTD128

Apparently, the chipset for the graphics card I am using is capable of driving either a single-link or a dual-link DVI connection.  What my card is doing when connected to the Dell monitor, I can't tell.

Message Edited by PaintedJaguar on 04-09-2004 01:51 AM

Since the 2001FP DVI interface only supports a single link, it would be operating in single-link mode.  A card capable of dual-link must identify when dual-link is not available on the monitor, and will only operate via single link.  The pinout specs for the 2001FP indicate that the pins necessary to support the second link are floating (not connected internally).

The head tech guy a BFG speculated that the GeForce card might be forcing dual-link mode for some unknown reason. I haven't a clue why the cable should make a difference, but so far it does seem to.

Shaggi on the 1800FP thread states that he tried a $100 Monster DVI cable from Best Buy with no result. I've looked at that particular cable and it is an 18-pin single-link.

I've been holding my breath waiting for one of these monitors to screw up while plugged into the Belkin, but so far it hasn't happened.

i just posted in the original thread (the original huge one) how i had this problem on a 1901fp with both a geforce fx 5700 AND a radeon 9600 xt.

in each case the dual link cable resolved the problem (for the most part).

http://forums.us.dell.com/supportforums/board/message?board.id=dim_monitor&message.id=33079&highlight=#M33079

finally got this to work with the oem cable by selecting the "Reduce DVI frequency on high-resolution displays" setting for my radeon 9600 xt. thinking that it might be a continuous problem for nvidia users given i don't think this is currently a driver setting for that gpu.

http://forums.us.dell.com/supportforums/board/message?board.id=dim_monitor&message.id=33110&highlight=#M33110

although i'm still trying to notice if the picture quality was better with the belkin ;-) although saving $50 would be nice.

Changing the driver settings does seem to help for some people with ATI cards.  But....

So far, every time I have seen the "Power Save Mode" problem, it has occurred during POST and DOS bootup.  That is to say, I never see any video display at all.  I have to wait until I'm sure Windows has finished loading, then shut down my machine "blind", using keystrokes.  Other times, I get "Can not display this mode" or no error message at all, and the screen stays black until Windows loads, then displays normally.

Even if I did have those DVI settings in my Nvida drivers, I don't see how it could help with these particular malfunctions, since they occur before the Windows drivers are loaded.