On Sun, 13 May 2007 22:31:18 +1200 Matthew Gregan <[EMAIL PROTECTED]> wrote:
> At 2007-05-13T14:22:33+1200, Steve Holdoway wrote: > > > up until now, I've been using one of my screens through a kvm switch, > > necessitating its use via analog video. Now, I'm ditching the kvm, and > > have connected both monitors digitally. Here's where the problems are > > starting. The right one just won't sync, and keeps blanking out. > > > Monitors are both Viewsonic vg2021m, and the card is a trusty nvidia > > GeForce GE 5200 with 128MB. > > Just so I'm sure I understand your problem, you're getting the expected > display on each monitor, but one of them periodically blanks out for a few > seconds and then comes back? Exactly > > The DVI electronics on that card probably won't be able to drive two DVI > ports at the kind of resolution you're asking for. At a lower resolution > you wouldn't have any trouble. > > I've seen similar problems with 5700 Ultras and 6800 Ultras. I had some > luck with using extremely short DVI-D cables and tweaking the refresh rate > down to ~50Hz to get a stable display in one case. > > NVIDIA's DVI implementation has been truly awful until pretty recently. The > 7xxx and upwards cards are decent, though. > > Your choices are: buy a better card, or use VGA for one of the two monitors. > You'll have to experiment to work out which DVI link is the weaker one. > From memory, it's the 'external' one that is the problem... see below. > > > (II) NVIDIA(0): NVIDIA GPU GeForce FX 5200 at PCI:3:0:0 (GPU-0) > > (--) NVIDIA(0): Memory: 131072 kBytes > > (--) NVIDIA(0): VideoBIOS: 04.34.20.16.00 > > (II) NVIDIA(0): Detected AGP rate: 8X > > (--) NVIDIA(0): Interlaced video modes are supported on this GPU > > (--) NVIDIA(0): Connected display device(s) on GeForce FX 5200 at PCI:3:0:0: > > (--) NVIDIA(0): ViewSonic VG2021m (DFP-0) > > (--) NVIDIA(0): ViewSonic VG2021m (DFP-1) > > (--) NVIDIA(0): ViewSonic VG2021m (DFP-0): 135.0 MHz maximum pixel clock > > (--) NVIDIA(0): ViewSonic VG2021m (DFP-0): Internal Dual Link TMDS > > (--) NVIDIA(0): ViewSonic VG2021m (DFP-1): 165.0 MHz maximum pixel clock > > (--) NVIDIA(0): ViewSonic VG2021m (DFP-1): External Single Link TMDS > > (II) NVIDIA(0): Assigned Display Devices: DFP-0, DFP-1 > > (II) NVIDIA(0): Validated modes: > > (II) NVIDIA(0): "1400x1050,1400x1050" > > (II) NVIDIA(0): Virtual screen size determined to be 2800 x 1050 > > > > Has detected the right monitor as being completely different to the left > > one! > > 165MHz is the maximum clock frequency for single link DVI. It turns out > that you can drive LCD panels at high resolutions and refresh rates by going > a little out of spec and running in 'reduced blanking' mode, which is > 135MHz. Problem is, the older NVIDIA cards can't really drive the link at > 165MHz reliably, despite what they advertise (there's probably a class > action waiting there for some keen party). > > The card have one internal TMDS and another add-on TMDS part (which is > separate chip, newer ones are usually both internal). This is the internal > vs external TMDS listed in the log output above. Only the internal TMDS > supports the sort of configuration that will allow it to run in the 135MHz > 'reduced blanking' mode. > > Work out which of the two DVI ports is associated with the external TMDS and > try running the monitor connected to that port via VGA instead. > > Cheers, > -mjg > -- > Matthew Gregan |/ > /| [EMAIL PROTECTED] Thanks for the input, now I know what I suspected was the problem is the reality. I know it's an old card, and a fairly old and slow machine, but it's a shuttle and I really like it. Maybe shelling out for a newer agp graphics card may be worth it. I'll see what trademe has to offer. My sound card ( a soundblaster! ) has just failed as well, which is annoying. Still it's been on for 3 years now, so I shouldn't complain if it starts getting a bit flaky - they do put out some heat. Cheers, Steve
