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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Ali Chen who wrote (55646)	4/15/1999 7:06:00 PM
From: Tenchusatsu	Read Replies (1) \| Respond to of 1577917

<You listen. I do not do assumptions. I speak from facts and CORRECT PLANNING OF DATA FLOWS in current PC architectures.> Ali, I've spoke with several people in the performance and architecture teams who will disagree with you. <You are effectively saying that some uneducated idiot gets data from memory, flushes processed data back, and let PCI/AGP to get them again, or the traffic across the memory bus is TRIPLED.> Well ... er ... YES. Except that this isn't some uneducated idiot's idea. Rather, this is called Direct Memory Access. What you are arguing for is the old way of doing things, which is writing data directly from the CPU to the devices. This requires constant CPU attention, mainly because CPU-to-PCI transactions are painfully slow compared to CPU-to-memory transactions. It's much better for the CPU to write the data to memory, then let the PCI or AGP device access that data directly from memory. This requires less CPU resources than the method you suggest. In other words, the CPU is free to do other stuff while the PCI and AGP devices do their thing. This Direct Memory Access model is in use today, from RAID SCSI hard drive controllers, to AGP graphics cards accessing textures from DRAM, to Gigabit Ethernet controllers which need a constant stream of data coming from the SDRAM. And I've got the data to back up my arguments. Tenchusatsu