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1.35V memory required in G751/G771/G551s (same as G750)

X-ROG
Level 15
Please note we fit 1.35V memory into the G751s (and G750s). Haswell CPUs require this and using 1.5V memory can sometimes cause problems along the lines of:
> Overheating
> Damage to the CPU IMC (due to the increased potential difference)
> Greater battery use than our stated values.

There is more discussion and recommendations of memory to use in this thread, as both G750 and G751's use the same Intel 4th Gen 'Haswell' processors: http://rog.asus.com/forum/showthread.php?33744-Upgraders-1-35V-memory-is-required!
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151 REPLIES 151

LoCk3d
Level 7
Hello, my G751JT arrived, I added one ram plate of 8GB, and they are in dual channel.
44411

LoCk3d wrote:
Hello, my G751JT arrived, I added one ram plate of 8GB, and they are in dual channel.
44411


LoCk3d, that's great news that the Crucial memory is compatible, can you please post the link to the item you purchased so others can get it too?

Did you check/compare the price of getting the original Samsung memory as a closer match?

LoCk3d wrote:
Hello, my G751JT arrived, I added one ram plate of 8GB, and they are in dual channel.
44411


How come your Command Rate is 1 ? I think mine is 2.

I have the Samsung memory 8x2 slots in G751JT . How I make it to Dual Channel , it is only Single now. And How can I make it to Command rate 1 ? it gives a nice boost in speed.

If I opened the back of the Laptop and saw 2 slots taken by the memory, where are the 2 others and how will I reach them if I want to use them ?

x7007 wrote:
How come your Command Rate is 1 ? I think mine is 2.

I have the Samsung memory 8x2 slots in G751JT . How I make it to Dual Channel , it is only Single now. And How can I make it to Command rate 1 ? it gives a nice boost in speed.

If I opened the back of the Laptop and saw 2 slots taken by the memory, where are the 2 others and how will I reach them if I want to use them ?


This will most likely void your warranty. This is why its advised to buy a model with 16gb ram so you dont have to do so. Basically you need to remove all the screws from the bottom, remove the optical drive and the screws under it and 2 or 3 screws in the hdd/ram bay. Then you have to remove the plastic and aluminium plates off the top of the fans and the pop the keyboard plate up from under the screen. There are a couple of cables there and all the guts of the laptop are then accessible. Ive done it, it tajes about ten to fifteen minutes. Dual Channel memory needs to be in corresponding slots. If cpu-z says you have ram in slots 1 and 2 then you want it in 1 and 3 and vice versa.

Edweird wrote:
This will most likely void your warranty. This is why its advised to buy a model with 16gb ram so you dont have to do so. Basically you need to remove all the screws from the bottom, remove the optical drive and the screws under it and 2 or 3 screws in the hdd/ram bay. Then you have to remove the plastic and aluminium plates off the top of the fans and the pop the keyboard plate up from under the screen. There are a couple of cables there and all the guts of the laptop are then accessible. Ive done it, it tajes about ten to fifteen minutes. Dual Channel memory needs to be in corresponding slots. If cpu-z says you have ram in slots 1 and 2 then you want it in 1 and 3 and vice versa.


You mean that's why we want the 16x1 model ? but even if I had this one, wouldn't I still need to do it to add the 2nd or 3rd one on the other slot for dual channel ? I can't understand what you mean with the 16Gb model, cause there is one thing but then there's the other which cancel this one. I have the 16Gb model 8x2 . but why would Asus do that, Dual channel is Double Faster than Single , to get the normal performance I should anyway get I need to void the warranty ? why................................... it's bloody gaming laptop and I am stuck now with Single Channel

What can I do now to get dual channel without opening the gutting of the laptop, how come other people can add the 3rd slot easy ? or maybe they did open it, they didn't say. How come there are people with G751JT with Command Rate 1T

x7007 wrote:
You mean that's why we want the 16x1 model ? but even if I had this one, wouldn't I still need to do it to add the 2nd or 3rd one on the other slot for dual channel ? I can't understand what you mean with the 16Gb model, cause there is one thing but then there's the other which cancel this one. I have the 16Gb model 8x2 . but why would Asus do that, Dual channel is Double Faster than Single , to get the normal performance I should anyway get I need to void the warranty ? why................................... it's bloody gaming laptop and I am stuck now with Single Channel

What can I do now to get dual channel without opening the gutting of the laptop, how come other people can add the 3rd slot easy ? or maybe they did open it, they didn't say. How come there are people with G751JT with Command Rate 1T


It's impossible. I mean if you have 2 x 8gb and as you say both (are you sure?) are in the service bay, then you must have double channel.
Check again. I'm quite convinced you have 1 stick in service bay and 1 under keybord area.
Because there are 2 banks per channel. Both channels have per 1 bank/slot in each place. Placing both sticks.in service bay makes double channel, if both are under keybord.thats also.double channel, you can also make double.channel with 2 sticks in difrent places.
Check service bay again, if you have there 1 stick of ram just relocate it to the other unocupied slot/bank.
It should work, is easy and dont have to take apart whole laptop

LoCk3d
Level 7
I am from Romania and I buy Crucial memory from convenience store. Cost 67 euro.

LoCk3d wrote:
I am from Romania and I buy Crucial memory from convenience store. Cost 67 euro.


LoCk3d, it's a wonderful time, we can also purchase Crucial memory from some convenience stores 🙂

Glad it worked out for you. The G751 seems less sensitive to mixing memory, this might have failed on the G750 from previous reports.

Have fun 🙂

hmscott wrote:
LoCk3d, it's a wonderful time, we can also purchase Crucial memory from some convenience stores 🙂

Glad it worked out for you. The G751 seems less sensitive to mixing memory, this might have failed on the G750 from previous reports.

Have fun 🙂


I can personally attest to the G751 not being very picky.
I have the standard Hyundai 8GB DDR3L-1600 1.35v CL10 module and I popped in a kit of 2 Kingston HyperX PnP 1.5v DDR3-1600 CL9 modules and it worked fine with a memtest86 and a couple hours of heavy gaming.

I'm not willing to take the chance of any damaged memory controllers or anything like that though - but my dad's K95 has been running with a 1.35/1.5v mix for over a year now with no issues.

aprilia1k
Level 7
Hi hmscott - it's very cool of you to help out here. The information and experience you impart is clearly helping many people, and likely a lot more who benefit without posting.

I definitely hear what you are saying - that mixing sodimm's of different make and/or specs is "hit or miss" - it almost seems like voodoo 😉 Apologies and will understand if this is TL;DR

It's easy to get confused about (for me anyway) - when I read the tech papers about dual-channel mem architecture etc.., it is implied and sometimes stated that the "matching" of dimm's is important if they are in "paired slots" (e.g. slot 1 and 3, slot 2 and 4 - in the 4-slot lappies we're discussing here) that can provide "dual-channel", or concurrent access if identical SODIMMs are used (to benefit from dual-channel's improved bandwidth). I.e., technically, slots 1 and 3 could be Kingston CL 11--- matched sodimms, and slots 2 and 4 could be Crucial CL 9--- matched sodimms and they'd be enabling dual-channel.

Nevertheless - actual real-life experience seems to counter this claim after all, right? I've got a G55VW that I am still loving - (3630QM, GTX660M, etc..); it is the finest laptop I've ever had (not just for obvious generational improvements, either). Anway - I've used CPU-Z and know my G55 has hynix (2x4gb, PC3-12800, 11-11-11-28) running at 1.5V. Further reading indicates that some folks have installed 1.5V in slots 1 & 3, and 1.35V in slots 2 & 4 ; It is my understanding that my G55 will support both 1.35 and 1.5V modules, so... a little more uncertainty here. Both Crucial and Kingston have their flavors of CPU-Z that you can run to determine what SODIMMs will work in your system, as well as "OEM compatible" short-lists (before I ran their scan utilities, they only showed sodimm with identical timings/specs to my system's orig. installed (except that none of them are recommending 1.5V SODIMMs for my G55VW)... (orig. factory is at 1.5V !!) More INTERESTINGLY, despite their pre-published "short lists" only showing the 11-11-11-28 modules, after I run their scanner utilities, they add their "performance" products to the list of Asus G55VW "compatible/supported" memory, SODIMMS with lower timings like 9-9-9-24 !! .. in other words, e.g., Crucial's page of compatible SODIMM for the Asus G55VW only had a single 8gb kit (2x4gb) with identical cas at CL 11, 1600mhz, etc. BUT after I ran their scan utlity, they expanded the list of compatible modules to include their "Ballistix" branded performance mem, with CL 9--- timing, etc.. and EVEN included some higher-freq PC3-14900 mem (technically, higher-freq mem should work fine at lower speeds I guess)

Again, what I've read is that in order to enable concurrent/dual-channel operation, each pair of slots (i.e. "concurrent-capable channels") need to have identical DIMMs... but technically, there's no reason that BOTH pairs have to be matched/identical DIMMs, because conncurrent access ("dual channel") only occurs on paired slots 1 & 3 (ch 1 and 2 pair), and paired slots 2 & 4 (ch 1 and 2 pair)... 1 & 3 could be identical Kingston, 2 & 4 identical Crucial sodimms, and you will have enabled dual-channel enhanced bandwidth. Regardless - I do understand that your advice is based upon real-world experiences reported from numerous sources, and much is in reference specifically to the "Haswell" equipped G7x1 - regardless, I do not mean to contradict what has been conveyed here. Just saying what my understanding of dual-channel has been. Basically, it's a case of "deviate at your own risk" it would seem.

I hope I haven't posted inappropriately, as this thread's intent is to alert G751 & G771 owner's to the Haswell's 1.35V requirement. I've just had trouble tracking down specific info for my situation, and this thread has knowledgeable and friendly contributors, as well as subject matter relevant to my situation/interests - at least I am a ROGer and happy ASUSer 😉

If I should delete or move this post, just say the word, no worries.

Stephen