DDR-2 voltages

The other day I did a RAM upgrade on a machine with DDR-2

When I pulled the old RAM I noticed that one stick was rated at 1.8v and
the other was 2.2v (I think..at any rate it was higher)

It had been that way with no problems.


My guess is that the mobo cannot assign different voltages to different
slots.

Just curious

philo wrote:
The other day I did a RAM upgrade on a machine with DDR-2

When I pulled the old RAM I noticed that one stick was rated at 1.8v and
the other was 2.2v (I think..at any rate it was higher)

It had been that way with no problems.


My guess is that the mobo cannot assign different voltages to different
slots.

Just curious

Yes, they're all run at the same voltage. One power
supply feeds all of VDimm. If you didn't do that,
suffice to say the power analysis would be a mess
(backfeed paths, thresholds etc).

Elevated voltages are used for Enthusiast ram, to
meet speeds lying outside the JEDEC spec. However,
if you're mixing enthusiast and non-enthusiast RAM,
the lowest common denominator applies - the slowest
stick determines the settings. The memory clock
is likely to be within JEDEC range, and if both sticks
run at 1.8V, they'd probably run fine.

And if someone said "you shouldn't mix enthusiast and
non-enthusiast RAM", I might tend to agree with that.
The enthusiast RAM has been tested (thoroughly) at the
enthusiast settings, and we can't really be 100% sure
the regular JEDEC settings work perfectly. It should,
but then nobody tested that to make sure. Testing
at multiple operating points costs a lot of money.

This is not a problem for a person like yourself,
who will be running memtest, Prime95, etc, before
shipping machines back to customers. To ensure all
is good, no matter what mix of bacon bits are used :-)
Your thorough testing will prove the memory is
all-good.

Paul

On 04/13/2016 06:45 PM, Paul wrote:
philo wrote:
The other day I did a RAM upgrade on a machine with DDR-2

When I pulled the old RAM I noticed that one stick was rated at 1.8v


snip
And if someone said "you shouldn't mix enthusiast and
non-enthusiast RAM", I might tend to agree with that.
The enthusiast RAM has been tested (thoroughly) at the
enthusiast settings, and we can't really be 100% sure
the regular JEDEC settings work perfectly. It should,
but then nobody tested that to make sure. Testing
at multiple operating points costs a lot of money.

This is not a problem for a person like yourself,
who will be running memtest, Prime95, etc, before
shipping machines back to customers. To ensure all
is good, no matter what mix of bacon bits are used :-)
Your thorough testing will prove the memory is
all-good.

Paul




Thanks for the good reply as always.

I had a look through my junk box and all is 1.8v RAM except for that one
stick.

I have very little DDR-2 left so I was going to order some new stuff
pretty soon.