Time not right when I reboot

[QueBert]

It's not the CMOS battery, my BIOS settings all stay intact. It started happening when I installed OSX, the only thing I can think of is when I switched the BIOS to AHCI it messed something up. I was just in OSX, time was right, rebooted to Win 7, time was wrong. Date seems to stay right. Switching between OS's leaves me having to reset the time. This makes no sense to me, anyone have an idea for me here?

thanks

 

[Numenorean]

You have them both on the same time zone?

 

[QueBert]

Yeah UTC -8:00 I'm about to boot back into OSX to see if the time is wrong again, I know it's always incorrect when I go from OSX to Win 7, but now I think about it I'm not sure Win to OSX results in the time messing up.

will update when I get back.

*EDIT* nope, booted up OSX and the time was off again, ARGH! Both are definitely set for the same time zone too

 

[theevilsharpie]

I'm no OS X expert, but if it's like most *nix-based OS's, it probably stores the system time as UTC. Windows, OTOH, uses your local time. If your time is consistently 8 hours off the correct time when booting into a different OS, the different time storage methods are likely the cause.

 

[QueBert]

I'm no OS X expert, but if it's like most *nix-based OS's, it probably stores the system time as UTC. Windows, OTOH, uses your local time. If your time is consistently 8 hours off the correct time when booting into a different OS, the different time storage methods are likely the cause.

Hummm, I would have never figured this out. My 3rd OS is Ubuntu looks like I should boot into that and see what happens. If this is the case I doubt there's a fix, really annoying too

 

[ManyBeers]

Hummm, I would have never figured this out. My 3rd OS is Ubuntu looks like I should boot into that and see what happens. If this is the case I doubt there's a fix, really annoying too

Ubuntu forum link

I just had this exact same problem when I installed Ubuntu 9.04 on a second hardrive
on my Gateway win7 run desktop. For some reason 9.04 kept UTC time.
In /etc/default/rsC..(or rcS).. UTC was set to Yes I reset it to No and the problem was gone.
My laptop dual/boots WinXP/ubuntu 8.04 on one drive and I never had the problem
because when I looked in /etc/default/rsC UTC was set to No.

Setup OSX to not use time synching with Internet servers and that way it will always use the hardware(bios) clock that Windows sets.
Basically if you can't figure out how to make OSX not use UTC time then
let your most used system be the sole time keeper for all 3 systems.

In the link I posted I actually created a new scheduled task in Windows to
Internet synch at Startup and I watched the clock go from 7 hours fast to correct local time while the desktop was loading. But I no longer need that task and it has been retired.