Wednesday, September 26, 2007
Does the Amount of RAM Have an Impact on Laptop Battery Life in Sleep Mode?
Posted by Jason Dunn in "THOUGHT" @ 12:08 PM
When I wrote my review of the Kingston 4 GB RAM upgrade for my Dell XPS M1330, one of the questions I wondered about was what type of impact the amount of installed RAM would have on battery life. When a laptop goes into sleep (suspend) mode, it has to provide a small amount of power to the RAM in order to maintain what's in memory. When a laptop goes into hibernate mode it writes everything to the hard drive, and thus no power is used while it sits there unused. I tend to prefer sleep mode myself, because it's usually faster to go into sleep mode, and faster to come out of it.
To test whether the amount of RAM has an impact on battery life while in sleep mode, I devised a simple test: I took my XPS M1330 with 4 GB of Kingston RAM, charged up the battery to 100%, then put it into sleep mode for 12 hours. I disabled the function where Vista will go into hibernate mode after "x" hours of being in sleep mode. While seemingly a good feature, on the XPS M1330 it would wake up the laptop (lights blazing) which results in the slot-load DVD drive making a "cha-chunk" sound. Having this happen in the middle of the night when the laptop is on a nightstand right next to your head is disturbing to say the least.
At the end of the 12 hours, I opened the lid on the laptop, waited about 20 seconds for the system to stabilize, and took a battery reading. The results? With 4 GB of RAM installed (2 x 2 GB sticks), and with the 9-cell M1330 battery, after 12 hours the battery level had dropped from 100% down to 91%. With 1 GB of RAM installed (1 x 1 GB stick) after 12 hours the battery level had dropped to 92%. Because this test required me to not use the notebook for 12 hours, I only did each test once.
My conclusion? The 1% variance is within the margin of error, so I believe that having 4 GB of RAM poses no significant added loss of battery life in sleep mode over having 1 GB of RAM. I might have seen a more noticeable difference if I had conducted this test over a 72 hour period, but I don't have a spare XPS M1330 sitting around.
Jason Dunn owns and operates Thoughts Media Inc., a company dedicated to creating the best in online communities. He enjoys mobile devices, digital media content creation/editing, and pretty much all technology. He lives in Calgary, Alberta, Canada with his lovely wife, and his sometimes obedient dog. He's mostly impressed with the XPS M1330.
To test whether the amount of RAM has an impact on battery life while in sleep mode, I devised a simple test: I took my XPS M1330 with 4 GB of Kingston RAM, charged up the battery to 100%, then put it into sleep mode for 12 hours. I disabled the function where Vista will go into hibernate mode after "x" hours of being in sleep mode. While seemingly a good feature, on the XPS M1330 it would wake up the laptop (lights blazing) which results in the slot-load DVD drive making a "cha-chunk" sound. Having this happen in the middle of the night when the laptop is on a nightstand right next to your head is disturbing to say the least.
At the end of the 12 hours, I opened the lid on the laptop, waited about 20 seconds for the system to stabilize, and took a battery reading. The results? With 4 GB of RAM installed (2 x 2 GB sticks), and with the 9-cell M1330 battery, after 12 hours the battery level had dropped from 100% down to 91%. With 1 GB of RAM installed (1 x 1 GB stick) after 12 hours the battery level had dropped to 92%. Because this test required me to not use the notebook for 12 hours, I only did each test once.
My conclusion? The 1% variance is within the margin of error, so I believe that having 4 GB of RAM poses no significant added loss of battery life in sleep mode over having 1 GB of RAM. I might have seen a more noticeable difference if I had conducted this test over a 72 hour period, but I don't have a spare XPS M1330 sitting around.
Jason Dunn owns and operates Thoughts Media Inc., a company dedicated to creating the best in online communities. He enjoys mobile devices, digital media content creation/editing, and pretty much all technology. He lives in Calgary, Alberta, Canada with his lovely wife, and his sometimes obedient dog. He's mostly impressed with the XPS M1330.
