1.5 Volt DDR3 with LGA2011

I have a workstation with LGA2011 CPU that died. It has Intel DX79TO
mainboard. The manual for that says it should use 1.35 V RAM.
This one had 4 sticks of standard 1.5 V RAM. It generally was left
running during the night, doing number cruching for at least 3 years.
I am curious if the extra 0.15 volt would be a problem. I thought
only going over 1.65 V would be fatal.

Anyway the board has a row of diagnostic LEDs and a hex display.
It gets up to b9, meaning it is detecting and initializing a fixed
drive. Also the LED flashes indicating memory initialization.
Then it powers powers down and starts up again. There are no beeps,
nor any display on monitor.
All the parts (RAM, power supply, drives, graphics card) work in other
PCs. So the mainboard or CPU are kaput.

wrote:
I have a workstation with LGA2011 CPU that died. It has Intel DX79TO
mainboard. The manual for that says it should use 1.35 V RAM.
This one had 4 sticks of standard 1.5 V RAM. It generally was left
running during the night, doing number cruching for at least 3 years.
I am curious if the extra 0.15 volt would be a problem. I thought
only going over 1.65 V would be fatal.

Anyway the board has a row of diagnostic LEDs and a hex display.
It gets up to b9, meaning it is detecting and initializing a fixed
drive. Also the LED flashes indicating memory initialization.
Then it powers powers down and starts up again. There are no beeps,
nor any display on monitor.
All the parts (RAM, power supply, drives, graphics card) work in other
PCs. So the mainboard or CPU are kaput.

In the spirit of debug, simplify.

Take the hard drive out of the picture. Disconnect
power and data cable.

Find an OS on a USB stick you can use. On my LGA2011 here,
not everything wlll boot on it. For example, my
crusty old Knoppix 5.3.1 DVD won't boot on it.
Because it simply wasn't expecting hardware like that.
Pick an OS for your USB key, that's a bit more
up to date than that.

*******

The 1.35V RAM is backward compatible with 1.50V applications.

https://www.jedec.org/news/pressrele...eases-spd-spec

"These devices are intended to be compatible with
existing 1.5V DDR3 systems and may operate without
restriction in those applications."

What JEDEC won't tell you, is what happens at 1.65V.
The company making the DIMM may have more to say on
the issue, but you may have trouble tracking down good
solid info otherwise.

And the two Intel docs for the DX79TO are sadly lacking.
Must be getting hard to find good tech writers.

Paul

On Mon, 30 May 2016 06:03:53 -0700 (PDT), wrote:

I have a workstation with LGA2011 CPU that died. It has Intel DX79TO
mainboard. The manual for that says it should use 1.35 V RAM.
This one had 4 sticks of standard 1.5 V RAM. It generally was left
running during the night, doing number cruching for at least 3 years.
I am curious if the extra 0.15 volt would be a problem. I thought
only going over 1.65 V would be fatal.

I was looking into building a setup with an LGA2011 socket a while ago
and did come across a warning to only use 1.35V RAM as 1.5V would
likely damage the CPU. It was either on the Intel ark site or the Asus
site. It may not be the socket but the particular CPU I was looking at.
What CPU do you have? Try googling the CPU and looking at the link to
the Intel site for it's spec.

--
Faster, cheaper, quieter than HS2
and built in 5 years;
UKUltraspeed http://www.500kmh.com/

wrote in part:
I have a workstation with LGA2011 CPU that died. It has Intel
DX79TO mainboard. The manual for that says it should use 1.35
V RAM. This one had 4 sticks of standard 1.5 V RAM. It generally
was left running during the night, doing number cruching for
at least 3 years. I am curious if the extra 0.15 volt would be
a problem. I thought only going over 1.65 V would be fatal.

It might be marginal, but I suspect you would have had problems
with your number crunching (convergence) if the RAM was bad.
When in doubt, test with memtest86+ .

Anyway the board has a row of diagnostic LEDs and a hex display.
It gets up to b9, meaning it is detecting and initializing a fixed
drive. Also the LED flashes indicating memory initialization.
Then it powers powers down and starts up again. There are
no beeps, nor any display on monitor. All the parts (RAM,
power supply, drives, graphics card) work in other PCs. So the
mainboard or CPU are kaput.

Looks like you've made a good start, and it is hard to diagnose from
a distance. But those diagnostic LED & hex generally are driven
by the CPU BIOS POST routines, so I doubt the CPU is broken.

It is possible (but rare unless hotplugged) for a mobo disk port
to go bad. More likely the disk does, but you say that is good.
Does that include booting from the disk? All it takes is one stray
write to sector 0 and a disk becomes unbootable. It might still
be recognized & readable if the partition table isn't clobbered.

-- Robert