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Rockbox mail archiveSubject: Re: DRAM 2MB -> DRAM 8MBRe: DRAM 2MB -> DRAM 8MB
From: Vladimir Pantelic <pan_at_nt.tu-darmstadt.de>
Date: Mon, 16 Sep 2002 17:02:03 +0200 Stuart Tedford wrote: > Excellent work. > > This mod should save a lot of battery power. Could you post the results > when you get round to doing a test? More RAM space for cool apps - YES Doubled battery life - NO! As we have a larger buffer to fill, the HDD has also to spin longer, so nothing gained here. What we would gain is less time spent with drive spinup if the buffer is 4x large. Assuming we use: 50mA when the HDD is off 300mA when the HDD is running (reading 1MB/second) 500mA to spin up for 3secs So with 2MB = 100secs of MP3 we have: 50mA + 300mA * 2/100 + 500 * 3/100 = 71mA average and with 8BM = 450 secs of MP3 we have: 50 mA + 300mA * 2/100 + 500 * 3/450 = 59mA average (not counting the extra current for the larger DRAM) The average current is reduced only by about 20% by making the buffer 4x larger ..... These values are just rough estimates, but I just wanted to show that a double buffer size does not make double play time. For this you would have to make the current consumption of the rest of the circuit much smaller. Regards, Vladimir Received on 2002-09-16 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |