Date: Sun, 5 Oct 1997 11:35:25 +0100 (BST) From: Robert Swindells <rjs@fdy2.demon.co.uk> To: babkin@hq.icb.chel.su Cc: hackers@freebsd.org Subject: Re: PCI slowness ? Message-ID: <199710051035.LAA00326@fdy2.demon.co.uk> In-Reply-To: <199710050539.LAA09048@hq.icb.chel.su> (babkin@hq.icb.chel.su)
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> The chipset is Intel Triton on some chineese motherboard > with 75MHz Pentium, memory is 60ns EDO. > Theoretical PCI throughput is 33M > of 4-byte transfers per second (the card claims to work > in burst mode). Theoretical memory throughput is at least > 10M of 4-byte transfers per second if we suppose that > the memory cycle with all overhead is 100ns and the > card reads by 4 bytes at a time. But the experiment > shows throughput of only 17MBps or 4.25M of 4 byte > transfers. Does the processor eats all the remaining > throughput (although I think it must load most of the > code it runs at idling into the cache) ? I thought that a 75MHz Pentium ran the PCI bus at 25MHz, not 33MHz. Are you sure that the bus on your system is at 33MHz ? ------------------------------------- Robert Swindells - GenRad Ltd rjs@genrad.co.uk - Work rjs@fdy2.demon.co.uk - Home
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