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Why would I not want to use 1.65v RAM on a Sandy Bridge MOBO?

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April 12, 2011 6:21:22 PM

Why would I not want to use 1.65v RAM on a DDR3 SB MOBO?

Why do they say to use 1.5v with Sandy Bridge?

Would OC'ing a 1.5v 1600 speed kit to say 2133 @ 1.65v (I don't know if this is possible, just in theory...if you could do it) hurt the mobo or RAM?

Would buying a 1.6v-1.65v kit for a SB MOBO be a bad idea if it has the speed, timings, and price you want?
a b } Memory
April 12, 2011 6:58:30 PM

Good question really. 1.5v is the voltage spec for Intel LGA1155. But I have seen a few sticks for the Sandy Bridge boards that are 1.6v, but nothing higher, so I can not recommend anyone try a 1.65v RAM. Raising a 1.5 speced stick to 1.6 would not cause any harm - I've done it. But I've not of anyone going higher than that for daily use, maybe someone around here has.
Hope this helps :) 
a b } Memory
April 12, 2011 7:31:51 PM

IIRC the memory controller for the sandy bridge chips has problems with burning up if the memory uses anything higher than 1.65V --- so using higher rated memory modules can cause the memory controller to run with too much voltage and burn out - thus they require modules rated for lower than 1.65v to be used !

HERE is a Tom's article on the problem
Related resources
a b } Memory
April 13, 2011 1:58:06 AM

Now THERE'S a good reason not to OC your RAM on a Sandy Bridge board!

Best solution

a b } Memory
April 13, 2011 2:59:23 AM
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TopGun said:
Why would I not want to use 1.65v RAM on a DDR3 SB MOBO? ?


No reason .... unless you plan on over volting .... kinda like hacking your GFX card to voltages beyond manufacturers stated limits and the ranting when card burns up. As the THG article says:
Quote:

Memory controllers inside the Core i7 processors support DDR3 memory. JEDEC specifies a standard voltage of 1.5V for that memory type, so this 1.65V limit would leave little leeway for over voltage within specification. This will sure cause enthusiasts to scrutinize over which modules they purchase more carefully. Currently, many enthusiast models go far outside the JEDEC standard of 1.5, coming in around 1.9V to reach rated specification.

Let us not forgot that manufacturers have always recommended against over voltage and clocking in some form or another – but it does not mean you cannot do it. We are pretty certain that this shouldn’t cause a big issue in the long run.


Now that was written 3 months BEFORE any hardware came out. No we know better,

http://www.clunk.org.uk/forums/overclocking/39184-p67-s...

Quote:
Sandy Bridge has only been around for a short time, but sadly, there is an incredible amount of confusion regarding certain aspects of voltage adjustment. The information below, comes directly from Asus, Gigabyte, Corsair and Intel PMO (Platform Memory Operations), and to the best of my knowledge is 100% correct at the time of writing this. Of course, if any new information comes to light, I will update this section.

Sandy Bridge does not demand only 1.5v modules, it will be perfectly happy with 1.65v modules too. If someone tries to tell you that you must have 1.5v modules, then they are either trying to sell them to you, or they have been reading misinformation, or both! Another point to consider here, is that in your BIOS, if you head to the memory voltage setting, and enter 1.5v, the text will remain white/grey, if you enter 1.65v, it will turn yellow, and it isn't until 1.73v that it turns red, so at the moment, I'd rest assured that 1.65v modules are OK to use, and I have had this confirmed by Asus, Gigabyte and Corsair so far, as soon as I hear from anyone else, I will update this again.

Sandy Bridge does not require there to be a maximum of 0.5v between the VDIMM value and the VCCIO and VCCSA values when 1.65v voltage modules are used.

BCLK Overclocking will not murder your CPU or motherboard. There is absolutely no evidence to support the rumours that adjusting the BCLK upwards on a locked or unlocked CPU will kill/damage it. What will happen, is that the system will become unstable, and you will lose control of things like your hard drive or graphics card, resulting in instability, corruption or the inability to start up properly. As with any overclocking induced instability, simply reduce the overclock and you will find that normality resumes - If you have suffered a SATA problem, then you may have to run your Windows repair console to get the boot loader back.



a b } Memory
April 13, 2011 3:04:40 AM

^+1 nice reference JackNaylorPE
Been trying to point that out a few times SB is no different then 1156 when it comes to dram voltage.
a b } Memory
April 13, 2011 3:08:18 AM

Thanks for the education Jack!
a c 97 } Memory
April 13, 2011 3:13:20 AM

TopGun said:
Why would I not want to use 1.65v RAM on a DDR3 SB MOBO?

Why do they say to use 1.5v with Sandy Bridge?

Would OC'ing a 1.5v 1600 speed kit to say 2133 @ 1.65v (I don't know if this is possible, just in theory...if you could do it) hurt the mobo or RAM?

Would buying a 1.6v-1.65v kit for a SB MOBO be a bad idea if it has the speed, timings, and price you want?


1) Realize that 1.65v ram is the same 1.5v ram that is binned, and capable of higher speeds when running at 1.65v. For this, they charge a price premium.
2) Intel specs say 1.5v. The max voltage is 1.65 before risking permanently damaging your cpu.
3) Sandy bridge has an excellent memory controller. Faster ram or better timings can be expected to improve your FPS by 1 or 2. Application throughput will similarly be improved by 1-2%. Synthetic benchmarks will shine, but are largely irrelevant. Not worth it in my opinion.
4) I would not pay a price premium for 1.65v ram. I might pay a bit more for 1.5v ram that runs at the same speed as 1.65v ram. I think ddr3-1600 @ 1.5v is about the right spot.
April 14, 2011 2:03:34 AM

I already bought some CL8 1600 @ 1.5v RAM for $84.99. I just wanted to know if I should have been including any 1.65v kits in my search. It sounds like the answer is that I should have included those in my possibles list. Hopefully I didn't miss out on any great deals, and hopefully this info will help someone out who's looking for SB RAM.
a c 97 } Memory
April 14, 2011 3:20:46 AM

TopGun said:
I already bought some CL8 1600 @ 1.5v RAM for $84.99. I just wanted to know if I should have been including any 1.65v kits in my search. It sounds like the answer is that I should have included those in my possibles list. Hopefully I didn't miss out on any great deals, and hopefully this info will help someone out who's looking for SB RAM.


One thing to check is to see that the ram is compatible with your motherboard.
The motherboard vendor will have a QVL list of ram kits that have been tested and are OK. But, they can't test everything.
Or, check the ram vendor's web site, and access their configurator. Enter your mobo, and you will get a list of their compatible ram.
If you should ever have an issue, you want certified compatibility from at least one side.
Fortunately, it seems that virtually all 1.5 DDR3 ram is compatible with sandy bridge.

$85 is a very good price for a 8gb kit of ddr3-1600. You did very well. Do not worry about performance.
a b } Memory
April 14, 2011 4:11:26 AM

Don't worry -- we won't be shopping for 1.5v or 1.65v RAM here soon. The Sandy Bridge "E" and Ivy Bridge CPUs both will likely require the 1.25v kits that are starting to hit retail. The 1.5v kits may work, but the 1.65v kits won't.
April 14, 2011 3:46:56 PM

Leaps-from-Shadows said:
Don't worry -- we won't be shopping for 1.5v or 1.65v RAM here soon. The Sandy Bridge "E" and Ivy Bridge CPUs both will likely require the 1.25v kits that are starting to hit retail. The 1.5v kits may work, but the 1.65v kits won't.


Are SB "E" and Ivy Bridge going to be a lot more expensive than current SB? Will they make SB prices drop when they come out? I was planning my whole build with the intention of using SB...did I make a mistake and just "wasted" $84.99 on 1.5v RAM?
a b } Memory
April 14, 2011 5:28:25 PM

SB-E will likely be at or near the high end of Intel's cost scale -- I'm guessing $999 or more for the top model, and maybe $599 for the "low end" SB-E.

IB is just a die-shrink of SB-MS (mainstream), so it will likely occupy the middle of the cost scale (above SB-MS, below SB-E) at least to start.

You didn't waste your money. The SB-MS CPUs we have now will be powerful enough for gaming at least for the next four to five years. By then you'll need to upgrade everything again anyway.
a c 97 } Memory
April 14, 2011 5:55:06 PM

TopGun said:
Are SB "E" and Ivy Bridge going to be a lot more expensive than current SB? Will they make SB prices drop when they come out? I was planning my whole build with the intention of using SB...did I make a mistake and just "wasted" $84.99 on 1.5v RAM?

From a historical point of view, new cpu's from Intel do not lower the price of older medels. On the used market, older less efficient cpu's tend to go down to meet the new price performance level.

I think the current 2500K will be the gamer's choice for at least another year, perhaps even more.
April 21, 2011 2:35:56 PM

Best answer selected by TopGun.
!