GeForce4 Ti 4200 64MB, Dell standard issue, ~2yrs old, using @higher resolution OK or "bad" for LCD?

[DualMonitors]

My 2-yr old Dell 8200 has the GeForce 4 Ti 4200 64MB that came with it, 1 DVI out max 1600x1200, and 1 VGA out max 1920x1200, clearly stated. So far, i've used it with a dual screen configuration with a Samsung 213T 21.3" LCD as my main monitor at DVI 1600x1200, and on the right side, an NEC 19" 1920NX as my second extended monitor at VGA 1280x1020.

i got my 2405FPW last week and sold my 19" NEC, moved my 21.3" samsung to my secondary monitor's position, switched it from dvi to vga and kept the resolution at 1600x1200, and moved my new 2405 to my main monitor's position and plugged it in at DVI. SURPRISE of surprises, magically, 1920X1200 appeared on the selection for resolution!!!??!!!

2 questions: will a "barely OK" signal for this DVI resolution, NOT mentioned by Dell or NVidia via their DVI output, cause any damage to my brand new 2405 Dell LCD?? Worried! Secondly, why in the world would there be this resolution at the DVI output if it clearly does NOT provide it as per all the documentation? why would this 1920X1200 magically appear on the selection menu when i plugged the 2405 in the DVI output? I was only plugging it in as an experiment, NOT expecting this to work and expecting to use the 2405 with my VGA output, and the secondary 21.3" screen via the DVI as the 1920x1200, according to the documentation, is ONLY support via the VGA output!

Puzzled here. thx in advance for helping me out!

 

[mwmorph]

not sure about iq or damage but windows detevcted your native resolution for the lcd as 1920x1200 so it offered the option fro that resolution.
for ex, my card goes up to 20x15 but my properties slider is automatically set to 12x10(my lcd's native resolution. and hides all resolutions above this native resolution(unless the hide unsupported display modes is unchecked).

 

[DualMonitors]

Mr. mwmorph: thx for your comment/response. i understand what you're saying, but i was thinking more along the lines of why 1920x1200 would even exist for this particular card, as this card's specs does NOT provide it! Windows XP and sense whatever it wants from the new 2405 monitor, but the upper limit should be limited automatically by what the video card is capable, right? is my thinking along the right track?

 

[mwmorph]

yeah. i understand, but my former ati rage pro didnt support 20x15@72 but it was available when my 23" crt display was plugged in. windows didnt limit me to what is supposed to be the max provided to the hardware either(though i never did run it above specs)

 

[JBT]

DualMonitor like a said a ton of times in our emails my 6800GT says the same thing for DVI it only suports up to 1600x1200 just like everyone elses. There is something I belive called blank interleaving which allows it to display highier resolutions such as 1920x1200. Your monitor will be fine.

 

[Nanobaud]

The digital 'DVI' signal has a maximum frequency, hence a maxiumum number of pixels / second (165 Million for single-link, which most cards and monitors are). If the signal complies with normal timing schemes, which accomodates the blanking period a CRT needs to scan the beam back to the beginning of the next line or frame, then the highest standard VGA resolution for which all pixels can be transmitted at 60Hz frame rates is 1600x1200. Since it is a digital signal, you can't just push it a bit faster and accept a slightly-noisy image, it is a limit. However, since an LCD does not need these silent blanking periods, the graphics card and monitor can agree that pixel information may be sent during certain periods of the blanking interval, allowing up to 1920x1200 @ 60Hz. This is what you see referred to as 'reduced blanking period', since the period during which the transmitted signal is silent is reduced. FOr it to work, both the graphics card and the monitor must support it, but it is not part of the DVI specification. This, I presume, is why you rarely see it documented as a feature of either cards or monitors. The card vendor doesn't want to commit to providing it because it can get frelled by the monitor, and the monitor vendor doesn't want to commit to it because it can get frelled by the graphics card. Also not all graphics cards, and perhaps not the receivers in all monitors really comply with the DVI spec all the way up to 165 MHz, and they might get away by using reduced blanking and lower frequencies at even 1600x1200. WIth these non-compliant signals, 1920x1200 with reduced blanking may even work on some DVI cables and not others.

If you are gatting a nice, solid image at 1920x1200@60Hz, consider yourself lucky (but not unique, it manages to work for most recent graphics cards and WUXGA LCDs most of the time) and be happy.

nBd

 

[JBT]

Originally posted by: Nanobaud
The digital 'DVI' signal has a maximum frequency, hence a maxiumum number of pixels / second (165 Million for single-link, which most cards and monitors are). If the signal complies with normal timing schemes, which accomodates the blanking period a CRT needs to scan the beam back to the beginning of the next line or frame, then the highest standard VGA resolution for which all pixels can be transmitted at 60Hz frame rates is 1600x1200. Since it is a digital signal, you can't just push it a bit faster and accept a slightly-noisy image, it is a limit. However, since an LCD does not need these silent blanking periods, the graphics card and monitor can agree that pixel information may be sent during certain periods of the blanking interval, allowing up to 1920x1200 @ 60Hz. This is what you see referred to as 'reduced blanking period', since the period during which the transmitted signal is silent is reduced. FOr it to work, both the graphics card and the monitor must support it, but it is not part of the DVI specification. This, I presume, is why you rarely see it documented as a feature of either cards or monitors. The card vendor doesn't want to commit to providing it because it can get frelled by the monitor, and the monitor vendor doesn't want to commit to it because it can get frelled by the graphics card. Also not all graphics cards, and perhaps not the receivers in all monitors really comply with the DVI spec all the way up to 165 MHz, and they might get away by using reduced blanking and lower frequencies at even 1600x1200. WIth these non-compliant signals, 1920x1200 with reduced blanking may even work on some DVI cables and not others.

If you are gatting a nice, solid image at 1920x1200@60Hz, consider yourself lucky (but not unique, it manages to work for most recent graphics cards and WUXGA LCDs most of the time) and be happy.

nBd

Thanks for the informative post.

 

[nitromullet]

Interesting question and interesting response(s). My question here though is why you would run $2500+ worth of LCD's on $50 worth of video card if you were the slightest bit concerned about damage?

 

[DualMonitors]

Thanks for your various responses. Finally, I got a definitive response from Nvidia! Essentially, if the TDMS transmitter is an "add on" (made by Silicon Graphics), then it can go beyond 1600x1200, and hence, on DVI, I can go up to 1920x1200. If the TDMS transmitter were "built in", then 1600x1200 is max. If the card were to be a dual DVI (mine is not, mine is 1 DVI and 1 VGA), then one DVI is built in, the other is Silicon Graphics! Clear at last!

 

[VirtualLarry]

Interesting info, both Nanobaud and DualMonitors. Now I'm curious though. Silicon Image (not "Silicon Graphics"), makes a new family of higher-speed TMDS transmitters. The onboard ones built into the NV and ATI GPUs, adhere to the standard spec of max 165Mhz signalling rate. The discrete SI TMDS chips, the newer ones, can go up past 200Mhz. So therefore, if the "reduced blanking interval" feature was used to obtain 1920x1200 support, then it should be possible to obtain it even via the built-in TMDS links If it requires the discrete TMDS, then it is likely being enabled by a faster-than-standard-spec TMDS link, combined with an LCD panel that can accept those higher-speed link connections.