How Do I Find The Ram Operating Voltage

I bought some RAM modules, and I want to find their operating voltages.
All the modules seem to work, computer boots into W10 pro, shows the right RAM amounts (8GB) in BIOS, computer and Speccy..

I'd like know what the spec. is and what voltage the modules are actually functioning under when they are in place.
The company websites do not seem to supply this information in a form that I can unambiguously understand and the companies involved are not contactable (last time I tried) or do not have that level of specific information.
The module p/ns are
Kingston - KVR1333D3S9/8G (this has "1.5V" on the label, uses Samsung chips)
Hynix - HMT41GS6MFR8C-H9 (C denotes "Commercial Temp & Normal Power")
Samsung - M471B1G73BH0-CK0
They are fitted (individually) to a Fujitsu Lifebook S752 core i5-3310 CPU, Windows 10 Pro
I have used speccy x64 portable to check parameters incl. p/ns- does the SPD table reflect the actual operating voltage (it has a value of 1.35V for all entries) ?
Maybe some incl. computer are dual voltage
The laptop originally came with 2 x Crucial CT51264BF1339 4GB modules. In the lifebook documention, it says it can use up to 2 x 8GB modules.

Thanks for sharing your knowledge and reassuring me on this one

Dumb_Question
23.May.2019!

 

DDR3 has a voltage of 1.35/1.5 volt.

 

->Eldon
Thanks, as ever. does the "/" mean 'and' or 'or' or 'xor' ?
I do not want go mixing RAM voltages as this could putting a 1.35 module into a position where it has 1.5V applied to it and it breaks.

Although the modules I bought were for a good price, 8GB modules, to me, are not cheap.

Dumb_Question
23.May.2019

 

They're designed to use between 1.35 and 1.5v, this usually means 1.35@1066/1333MHz, 1.5@1866, though the best RAM, esp. full size desktop sticks, can often be used safely over a wider range (I use 1.28@1600 > 1.7@2,400 on full size).

I'd start with 1.35@1600 9,9,9,24 for each stick with some stress testing, then test the best two at the same settings, more voltage = more heat, not something that's desirable in a notebook, undervolting would be better, though you probably won't get much choice, if any, of voltage and timing settings in a notebook.

 

Thank you Satrow., though I'm not sure I quite understand.
I didn't think I had any choice over the speed or operating voltage. I've seen nothing in the BIOS which makes me think I can change that. Apart from the Samsung, other RAM is spec'd at 1333MHz, and that's the speed I get in Speccy (665MHz). I don't know what voltage they're at, could the board is fixed at 1.35V for the RAM, or fixed at 1.5V, or can detect the what the RAM needs, and sets it appropriately.
I'm not sure what speed the Samsung RAM was operating at, but I think it was also 1333MHz, and the RAM was being down-clocked automatically to that speed.

I think the board voltage is not fixed at 1.5V, because the crucial RAM that came with the laptop is the 'BF' type not the 'BC' type, which I recently read means the operating voltage is 1.35V. But I don't know if this RAM can operate at either 1.35V or 1.5V

Dumb_Question
23.May.2019

 

Okay, the notebook has an IvyBridge chipset which defaults to 1333MHz and it's almost certainly using 1.35v. 1600MHz was 'allowed' by Intel for this chipset and 1.5v was the standard 'limit' (1.75v was the absolute but no-one volts that high).

For a normal notebook it makes sense sense to stick to the lower range of defaults for less heat/longer battery life, the main thing that 'suffers' is the potential for better graphics performance as that uses the System RAM too.

During the IvyBridge period DDR3L was introduced, that specified lower voltage, though 1.35v was still the default

The RAM, at least if it's from a good maker, can readily cope with 1.35 > 1.5v as it's part of the DDR3 standards. Your sticks all look better than good

If any two work together, you're good to go - I'd try the Samsung chips

 

Thanks, Satrow
Your posts imply that there is no way of determining the actual operating voltage of the RAM (I remember now that there was an old program called MBM5 which allowed you to see the CPU voltage in real time, and another, name is in the grey matter but I can not recall (SiSoft Sandra !), gave you detailed component info but you had to refresh it to get the latest values - I had it on my old XP system (awaiting repair)). Speccy won't do it.
I seem to remember recently reading that the chipset was H76 mobile.
Thanks for that tidbit about DDR3L - I thought that meant 1.35V only.

Dumb_Question
24.May.2019

 

more info. and correction

I have installed Sandra Lite
I have looked at all the modules again.
Not sure if its telling me the specification or actual operating conditions, there are two sections 'logical' and 'memory'
The memory section I am fairly sure reports the (nominal) specifications, it lists each module separately in detail. Here I noticed that contrary to what I wrote earlier, the two Crucial 4GB modules are different, one being the higher voltage BC-type module and the other the lower voltage BF-type. Despite this difference they work together, and have the same timings, both in logical section and memory/specification sections (table), where the voltage difference is apparent. I assume they are working at a common voltage though it doesn't say. Speccy also confirms dual channel mode, which I had thought you needed closely matched pairs to achieve (I now realise that this not so, and only certain parameters must match- not necessarily the manufacturer !)
In the logical and specification section Sandra gives a speed of 2 x 800MHz, the specified speed of the module.

Dumb_Question
24.May.2019

 

I can't think of anything that will give the 'live' voltage for RAM, 'nominal' (JDEC and XMP) is shown by CPU-Z and many others. 2x800 (1600MHz) can be regarded as 'optimal max.' (non-overclocked for Ivy, up from 1.333MHz on SandyBridge).

Actual settings in the notebook BIOS might vary, early designs on older BIOS versions might be 1.333, later designs/BIOS are more likely to use 1.600.

You don't have any options to change theses settings so use the 'pair' with Samsung chips.

 

Thanks for all your help, Satrow (not forgetting Eldon)
I think my BIOS is pretty old, you're right
I see the sense in your recommendation; however, you may have noticed that I have ended up with 3 modules where only 2 would fit. Because of errors in purchasing strategy (perhaps I am too pessimistic), I have another what should be Samsung 8GB modules in transit, which ought to be a better fit all round, so I'm waiting on them.

(I looked up the spec on the Samsung chips on the Kingston module and they're 1.35V DRAMs, despite the module saying it's a 1.5V module [I realise there may be other factors causing Kingston to recommend 1/5V operation])

Dumb_Question
24.May.2019