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1.5v vs. 1.35v RAM in 2012 cMBP

W

whdigital

macrumors regular
Original poster
Jul 22, 2011
124
1
Opened a new thread because there's information in other threads, but confusion between last years and this years models...

The 2012 MBP (non-retina) specs 1.35v RAM and OWC sells a 16GB kit with that voltage. Corsair Vengeance has one at 1.5v, but I can't seem to tell if auto-switches to the lower voltage. Anyone know what the difference is, if any, in terms of compatibility and performance?

These new MBPs run cooler, quieter and with decent battery life. I don't want to do a thing to jeopardize that!
 
I'm curious about this too. I ordered 2x4 GB memory sticks (Corsair Vengeance) and didn't realize that they were 1.5v instead of 1.35. They should arrive today so I will probably wait to put them in until I have a better answer.

After googling the question there seems to be some conflict as to whether or not it is safe to put 1.5v sticks into IB laptops. May just cancel the order and order 1.35v from Crucial.
 
Yep, and getting people to NOT chime in because they are "running them fine" in last year's MBP is the problem. There's conflicting info here as well...

So Crucial has some at 1.35v? I will check those out. You might also look at these, although they are more $ than I was hoping for:
http://eshop.macsales.com/item/Other World Computing/1600DDR3S16P/

----------

Found the Crucial ones - even more: :(

http://www.crucial.com/store/partspecs.aspx?IMODULE=CT2KIT102464BF160B

I suspect lower voltage is better all around. The question remains whether the higher voltage causes any real issues.
 
Yea, I did the compatibility thing on Crucial's website and all of the memory is 1.35v. I'm just going to play it safe, so I am returning the 1.5v sticks that arrived today from Newegg and ordering from Crucial.

I'm only ordering 8GB so it's only like $55. Ouch, 16GB is a little pricier...more than triple the price for double the memory.
 
Personally, I would go with 1.35V. It may not be measurable, but your CPU will run a little cooler. Using less power is the whole reason behind the lover voltage RAM. Why not open the MBP and see what Apple is using. Google the chip numbers for the specs.

The broad spec for DDR3 is 1.2 to 1.5v. DDR3L at 1.35v is a subspec within that spec. To confuse the issue, there is also 1.25v DDR3U.

If the next generation DDR4 RAM is released this year, it will probably be used in the 2013 MBPs. DDR4 operates at 1.05 to 1.2v.
 
drambuie said:
Personally, I would go with 1.35V. It may not be measurable, but your CPU will run a little cooler. Using less power is the whole reason behind the lover voltage RAM. Why not open the MBP and see what Apple is using. Google the chip numbers for the specs.

The broad spec for DDR3 is 1.2 to 1.5v. DDR3L at 1.35v is a subspec within that spec. To confuse the issue, there is also 1.25v DDR3U.

If the next generation DDR4 RAM is released this year, it will probably be used in the 2013 MBPs. DDR4 operates at 1.05 to 1.2v.
Click to expand...

Sounds good. Thanks Drambuie. I started the return process already so I might as well just return the 1.5v and order 1.35v. Not really in a huge rush to replace the RAM as I don't have any new photos/videos to edit at this time.
 
Concorde Rules said:
This is, of course, that the MBP has the ability to run the memory at 1.35V...

No way to check either. :(
Click to expand...

Well, the 2012 cMBP absolutely can run 1.35v RAM and that's what it ships with. The 2011 models take 1.5v from what i understand.
 
Concorde Rules said:
This is, of course, that the MBP has the ability to run the memory at 1.35V...

No way to check either. :(
Click to expand...

Crucial's website states that they tested the 1.35v RAM on my current model and guarantees that it is compatible, so I guess I'll have to take their word for it. OWC (MacSales) also shows 1.35v RAM compatible for my model, as well.
 
mickryebee said:
Crucial's website states that they tested the 1.35v RAM on my current model and guarantees that it is compatible, so I guess I'll have to take their word for it. OWC (MacSales) also shows 1.35v RAM compatible for my model, as well.
Click to expand...

compatible != it running at 1.35V.

1.35V memory will run at 1.5V...
 
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Concorde Rules said:
compatible != it running at 1.35V.

1.35V memory will run at 1.5V...
Click to expand...

I think you aren't dialed in to the issue here. NEW 2012 MBPs call for 1.35V. They will take 1.5V apparently, but trying to determine relative value of sticking with what appears to be only 2 sticks made that 1.35V.
 
I've just pulled the stock Apple RAM out of my 2012 cMBP and replaced it with 1.35v Crucial RAM. The Stock RAM is Samsung, and the code on it (M471B5273DH0) appears to relate to both 1.5v and 1.35v RAM. I don't immediately see any way of identifying if the RAM I've removed is the 1.5v or the 1.35v variety.

Concorde Rules said:
compatible != it running at 1.35V.

1.35V memory will run at 1.5V...
Click to expand...
The SPD of the SODIMM contains information about the required voltage; so yes, on an Ivy Bridge system 1.35v SODIMMs will run at 1.35v.
 
whdigital said:
I think you aren't dialed in to the issue here. NEW 2012 MBPs call for 1.35V. They will take 1.5V apparently, but trying to determine relative value of sticking with what appears to be only 2 sticks made that 1.35V.
Click to expand...

Where does Apple say the cMBP runs DDR3L? (1.35V)

cMBP 2012 = DDR3 = 1.5V
rMBP 2012 = DDR3L = 1.35V

Apple's 2012 Manuals aren't uploaded yet, so can't check the specs.

I don't think there would be any issues running 1.5V memory aside from the possibility of instability if they are force fed 1.35V or the reduced battery life/heat if running at 1.5V

DrJohnZoidberg said:
I've just pulled the stock Apple RAM out of my 2012 cMBP and replaced it with 1.35v Crucial RAM. The Stock RAM is Samsung, and the code on it (M471B5273DH0) appears to relate to both 1.5v and 1.35v RAM. I don't immediately see any way of identifying if the RAM I've removed is the 1.5v or the 1.35v variety.


The SPD of the SODIMM contains information about the required voltage; so yes, on an Ivy Bridge system 1.35v SODIMMs will run at 1.35v.
Click to expand...

Given that samsung stick is able to run at 1.35V (it is in the spec, so it must be able to run at that), then it does infact run at 1.35V.
 
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Concorde Rules said:
Where does Apple say the cMBP runs DDR3L? (1.35V)

cMBP 2012 = DDR3 = 1.5V
rMBP 2012 = DDR3L = 1.35V


Given that samsung stick is able to run at 1.35V (it is in the spec, so it must be able to run at that), then it does infact run at 1.35V.
Click to expand...

Exactly. This same Samsung stick(s) is in my 2012 cMBP so it does "call for" DDR3L.
 
For what it's worth, I had 16GB 1.5v RAM installed on my 2011 15" MBP i7, and shortly thereafter the logic board failed. I read online afterwards that only the 17" model was able to handle 1.5v.

My current 17" has 1.5v and runs it just fine with no issues. But if you have a 15" or 13" MBP, I would be safe and go with the 1.35v.
 
Has anyone had any more luck discerning whether the cMBP is using 1.5v or 1.35v RAM as standard?

The Samsung M471B5273DH0 RAM that I pulled from mine comes in two versions; 1.5v and a 1.35v (which is backward compatible with 1.5v). The 1.35v version appears to be newer (starting May 2012) than the 1.5v version, but there is no indication the 1.5v version has been discontinued; and even if Apple is using the newer 1.35v version, there is nothing to say they aren't using it in 1.5v mode.

Having said that, the rMBP (wich uses 1.35v DDR3L) is - excluding the screen - technologically identical to the cMBP, so it makes sense that the cMBP is also using 1.35v RAM (though the rMBP uses Hynix chips).
 
DrJohnZoidberg said:
Has anyone had any more luck discerning whether the cMBP is using 1.5v or 1.35v RAM as standard?

The Samsung M471B5273DH0 RAM that I pulled from mine comes in two versions; 1.5v and a 1.35v (which is backward compatible with 1.5v). The 1.35v version appears to be newer (starting May 2012) than the 1.5v version, but there is no indication the 1.5v version has been discontinued; and even if Apple is using the newer 1.35v version, there is nothing to say they aren't using it in 1.5v mode.

Having said that, the rMBP (wich uses 1.35v DDR3L) is - excluding the screen - technologically identical to the cMBP, so it makes sense that the cMBP is also using 1.35v RAM (though the rMBP uses Hynix chips).
Click to expand...

Well, my Crucial 1.35v sticks are being delivered today, so I will install them and let you know when I get a chance. Hopefully, everything goes smoothly.
 
mickryebee said:
Well, my Crucial 1.35v sticks are being delivered today, so I will install them and let you know when I get a chance. Hopefully, everything goes smoothly.
Click to expand...
You won't have any problems running 1.35v RAM. I've had the Crucial RAM in my cMBP for a couple of days and everything is fine. Ivy Bridge is designed to run with 1.35v RAM, but it's still not clear if Apple is using 1.35v or 1.5v with these 2012 cMBPs as standard.

If you could run a Geekbench (or any other memory benchmark) test before and after installing the RAM It would be good information for future reference. I had intended to do so, but I was too impatient to get the RAM installed :eek:
 
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whdigital said:
Well, the 2012 cMBP absolutely can run 1.35v RAM and that's what it ships with. The 2011 models take 1.5v from what i understand.
Click to expand...

I have a Late 2011 Macbook Pro Core i7 and I tried to install two 8GB sticks of Mushkin Enchanced DDR3 1600Mhz (PC12800) which run at 1.35V (i bought from newegg.com) and my mac recognized the 16GB with no problem but it downclocked the ram speed to 1333Mhz. I know my model supports 1600Mhz ram so I went and sent the Mushkin's back and resorted to getting the Corsair Vengeance 1.5V which EVERYONE seems to be raving about. Thankfully they run at 1600Mhz as advertised!
 
Already put them in. Sorry, didn't run Geekbench beforehand. Everything is running great though.

I did notice that Geekbench and CPU-Z both list my RAM running at 798mhZ instead of 1600. Is this normal? It's almost half of 1600 so it seems like it may be a converted number or something, but let me know if this is normal, or if it should say 1600.
 
mickryebee said:
Already put them in. Sorry, didn't run Geekbench beforehand. Everything is running great though.

I did notice that Geekbench and CPU-Z both list my RAM running at 798mhZ instead of 1600. Is this normal? It's almost half of 1600 so it seems like it may be a converted number or something, but let me know if this is normal, or if it should say 1600.
Click to expand...

DDR => Double Data Rate

800MHz clock = 1600 MHz Effective Clock.

The memory speed is a strap (in this case 8x) of the BCLK (which is 100.0 optimally). There is however often variations in the BCLK, which means that your BCLK is probably at 99.75 which is fine.
 
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