Well, let's think about that for a moment... Let's say we're doing 1920x1200 in 24-bit color at 60hz. That's 527 MiB/sec. This is slightly more than 2 PCIe 1.x links. If we're smart and only transfer 3 bytes/pixel, that's almost 400MiB/sec. How much power does it take to run two PCIe 1.x links continuously?
If we have on-board memory on the graphics card, we can calculate the additional power from adding the extra memory. Everything else should be the same. Same video controller, similar memory controller to the host, etc. We can determine the power necessary to run PCIe. So the tradeoff is some proportion of extra memory versus PCIe link bandwidth. There are other hidden costs, but I expect them to be minor. On Tue, Nov 13, 2012 at 9:50 AM, Nicolas Boulay <[email protected]> wrote: > Even a single DRAM chip using 16 bits bus, will be much faster than > using the PCI-e link for video memory. > > You could have few MiB on chip, but DRAM chip are 256 MiB now. > > Beside that, having a fully internal frambuffer, could save a lot of > power for pure 2D graphics. But today graphical server wait arround > 32/128 MiB to do compositing. > > 2012/11/13 "Ing. Daniel Rozsnyó" <[email protected]>: > > Thinking again of my minimalistic mini-pcie graphics card... can a PCI > > device initiate a transmission of a memory block? (DMA/bus-master). > > > > Then it would be even possible to leave out the local memory on the > card, so > > it is one chip less and a lot easier PCB design (cons are that the > bandwidth > > might be limited by the 1x pcie interface to 2.5G or 5G). > > > > Can anybody confirm that this might work ? > > > > > > Daniel > > > > _______________________________________________ > > Open-graphics mailing list > > [email protected] > > http://lists.duskglow.com/mailman/listinfo/open-graphics > > List service provided by Duskglow Consulting, LLC (www.duskglow.com) > _______________________________________________ > Open-graphics mailing list > [email protected] > http://lists.duskglow.com/mailman/listinfo/open-graphics > List service provided by Duskglow Consulting, LLC (www.duskglow.com) > -- Timothy Normand Miller, PhD Assistant Professor of Computer Science, Binghamton University http://www.cs.binghamton.edu/~millerti/<http://www.cse.ohio-state.edu/~millerti> Open Graphics Project
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