> >David Gillett wrote: > >> Wayne Ramlogan <[log in to unmask]> asked: >> >Is it possible to mix RAM; EDO and SDRAM PC100 or EDO and SDRAM ... snip ... >> My personal conjectures (somebody correct me if I'm wrong) are as >> follows: >> >> 1.) Your edo is "rated" 60-70 nanoseconds. >> 2.) Your sdram is "rated" 6-10 nanoseconds. >> 3.) Your memory bus runs at one constant speed. >> 4.) This one constant speed with mixed mem. modules would have to >> approximate the speed of the slowest module. >> >> Hence you would be running sdram rated at 6-10 ns at something like >> 60-70 ns, a potential waste of resources. Fine for a short test period >> (if it works: I never take stuff like this for granted). Definitely not >> recommended in the long run. > > This might be true IFF the ns rating of SDRAM was measuring the exact >same thing as the ns rating of FPM and EDO does. But if it did, it I give up. What _are_ the ns ratings of EDO, SDRAM, etc measuring??? >would be wasteful to use SDRAM in a machine with an FSB any slower than >about 500 MHz or so; the fact that SDRAM is routinely used with FSB >speeds of 66-100 MHz makes it pretty clear that you cannot just compare >ns ratings across types this way. Yeah, I thought I might be getting myself in trouble here. Lets see if I can further "lock and load" and draw a perfect aim on my foot <grin>. Is it in any way reasonable to conceptualize TOE (Time Of Execution) for a simple fetch instruction as: TOE = Tb + Tma +Tb where Tb is time required for transfer on the mem. bus and Tma is time required for memory access (address resolution, etc) ? If this is massively inaccurate, do you have a better model? In my insane dream, the Tma for, say, 60 ns EDO, when divided by the Tma for 10 ns SDRAM, _approximated_ the ratio of the 2 ratings (60/10). Crazy, huh? Maybe I can learn something here ... Prosit, David N. ********************************************************************** ** David Nasser ** [log in to unmask] ** ** Univ. Mo. St. Louis ** ** **********************************************************************; Curious about the people moderating your messages? Visit our staff web site: http://nospin.com/pc/staff.html