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View Full Version : S3 suspend mode: safe for overvolted memory?


gnf
03-22-2007, 04:17 PM
When one uses the S3 ACPI suspend state as opposed to the default S1 sleep state (eg. "sleep" in Vista and "deep sleep" in most other operating systems), the processor and most of the motherboard is switched off. Fans are all turned off. Only power to the memory remains. Only about 7 watts is consumed. One can wake up the PC to full operation within 2 or 3 seconds as no POST is required.

I'm unsure of what happens to the memory voltage and clock speed in the S3 state. I'd like to know if it's safe to use for overclocked systems, given that no fan is running. I *think* that the northbridge runs much slower, only enough just to keep refreshing the RAM, but am not sure. I'm not sure whether the ACPI spec provides for decreased voltage if one has set a specific (overvolted) DRAM voltage for normal operation in BIOS.

Does anyone know the answer to this?

BTW, if some people are having problems with wake-up from S3 suspend in Vista, here is a collection of patches. Thank goodness I'm an Ubuntu user.
http://neosmart.net/blog/2006/vistas-hideous-wakeup-support/

Adidas4275
03-22-2007, 04:52 PM
interesting question... i am sure the HTPC people will be interested as well

ziddey
03-22-2007, 06:28 PM
hmm iirc s3 puts ram into slow refresh cycle. perhaps you could try s3 mode and then take a dmm to measure voltage. also, measure heat with thermistor or something