4 ms·

Heh, you solved one problem by creating another. It works fine if you only have 1 display, then you can run everything display side. But now lets say you have

Heh, you solved one problem by creating another. It works fine if you only have 1 display, then you can run everything display side. But now lets say you have 3 displays. Now each built in GPU has have the ability to talk to other items on the PCIe bus, not just the controller. This sounds like a blessing. The host PC would only have to upload the window contents once, then each display would send the information to each other. Simple right? But now we have to deal with hardware latency, and cross vendor standardization. Which are largely problems then bandwidth.

kalleboo 12y ago
I never had any problems running multiple displays on separate PCI graphics cards on my 2002 PowerMac G4, why would that be a bigger challenge now?
- JohnBooty 12y ago
  Each of the PCI graphics cards in your 2002 PowerMac was using a long-established standard signal (VGA) to communicate with the monitors, so there was no problem. If you build the graphics card into the monitor, you'd need a new (non-existant) standard to pipe graphics bitmaps and draw instructions between the PC and the monitor. (Unless X is up to the task... hahah) OR, you could just extend PCI express over cables to the monitors. Which would work (you can already buy PCI express breakout boxes) but then you have much greater latency between the card and the system, etc etc etc.
  - kalleboo 12y ago
    > OR, you could just extend PCI express over cables to the monitors We already have this http://en.wikipedia.org/wiki/Thunderbolt_(interface) http://en.wikipedia.org/wiki/Thunderbolt_(interface) Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into one serial signal alongside a DC connection for electric power, transmitted over one cable. Up to six peripherals may be supported by one connector through various topologies. Not enough PCIe lanes to get enough performance for games but it should be fine for desktop applications.
  - 7952 12y ago
    Why exactly should latency be such an issue for graphics cards? If the graphics card only needs to refresh the screen every 15ms what difference would a few nano seconds make for the signal to travel down a wire? I'm guessing that reading to PCI express if already >100ns for large payloads.

kalleboo 12y ago

I never had any problems running multiple displays on separate PCI graphics cards on my 2002 PowerMac G4, why would that be a bigger challenge now?

JohnBooty 12y ago
Each of the PCI graphics cards in your 2002 PowerMac was using a long-established standard signal (VGA) to communicate with the monitors, so there was no problem. If you build the graphics card into the monitor, you'd need a new (non-existant) standard to pipe graphics bitmaps and draw instructions between the PC and the monitor. (Unless X is up to the task... hahah) OR, you could just extend PCI express over cables to the monitors. Which would work (you can already buy PCI express breakout boxes) but then you have much greater latency between the card and the system, etc etc etc.
- kalleboo 12y ago
  > OR, you could just extend PCI express over cables to the monitors We already have this http://en.wikipedia.org/wiki/Thunderbolt_(interface) http://en.wikipedia.org/wiki/Thunderbolt_(interface) Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into one serial signal alongside a DC connection for electric power, transmitted over one cable. Up to six peripherals may be supported by one connector through various topologies. Not enough PCIe lanes to get enough performance for games but it should be fine for desktop applications.
- 7952 12y ago
  Why exactly should latency be such an issue for graphics cards? If the graphics card only needs to refresh the screen every 15ms what difference would a few nano seconds make for the signal to travel down a wire? I'm guessing that reading to PCI express if already >100ns for large payloads.