Llano IMC and max memory voltage?

VirtualLarry

No Lifer
Aug 25, 2001
56,570
10,204
126
Just wondering what the memory voltage limits were for LLano. Figured that some people might want to overclock their RAM, to see what kind of increased bandwidth they get. Given that this is 32nm (AMD 32nm), things are probably different from AM3 rigs. I know SB is 32nm, and prefers 1.5v. Wondering if AMD 32nm is 1.65v tolerant or not.
 

Zap

Elite Member
Oct 13, 1999
22,377
7
81
That's a very good question. AMD has had an IMC since well before Intel, and I recall some problems even back in the socket 754/939 days with this. I specifically recall some discussion at the now defunct DFI Street forums regarding this. Those old DFI motherboards had a jumper to raise memory voltages up really huge. People were talking about how their CPUs died and some postulated voltages of memory having an effect. I think they came to the conclusion that you had to raise CPU voltages as well. I recall one guy testing his working rig by UNDERvolting his CPU while using raised voltages for RAM. The result was that his CPU promptly died.

I don't think it is that big of a deal these days because DDR3 is so fast that only benchmark queens care about overclocking RAM a huge amount, and because of Intel CPU considerations most of the super high voltage DDR3 seen in the past (up to 1.8v+) are now no longer on the market.
 

Concillian

Diamond Member
May 26, 2004
3,751
8
81
I don't think it is that big of a deal these days because DDR3 is so fast that only benchmark queens care about overclocking RAM a huge amount...

Well, if there's a CPU that makes an argument for "no amount of memory speed is enough" it's one with an integrated GPU large enough that the memory speed is a significant bottleneck to the GPU performance.

I am waiting for them to be available for building so I can let my friend know it's time to upgrade (not a gamer, but occasionally plays... wants ITX form factor above all performance considerations). For that kind of build, you want all the memory speed / latency you can get. I foresee that a certain segment will be pushing the IMC of the Llano as much as possible.
 

Arkadrel

Diamond Member
Oct 19, 2010
3,681
2
0
I don't think it is that big of a deal these days because DDR3 is so fast that only benchmark queens care about overclocking RAM a huge amount, and because of Intel CPU considerations most of the super high voltage DDR3 seen in the past (up to 1.8v+) are now no longer on the market.


ddr3scaling-16x10.png



~51fps vs ~63fps, from useing DDR3-1333 vs DDR3-1866.

Thats tangable... When you overclock your iGPU and CPU, you ll need more memory bandwidth with the Llanos (desktop versions).

Overclocking ram on a Llano system could pay off well.
 

notty22

Diamond Member
Jan 1, 2010
3,375
0
0
AMD had a dragon overclocking guide for Phenom II. In it is this warning for memory voltage. It stuck in my mind, when I read the guide in the past.
I'm going to assume, similar caution should be used on 32nm cpu's.

http://sites.amd.com/us/Documents/AMD_Dragon_AM3_AM2_Performance_Tuning_Guide.pdf
Page 6
System Memory voltage adjustment (5)
This one can also have two sliders (depending on the
motherboard that is being used). “Memory VDDQ”
(memory core voltage) that defaults to 1.8V is the slider
that should be adjusted in most cases. The other slider
(Memory VTT) will adjust automatically according to the
VDDQ slider adjustment. Normally the VTT level should
be 50% of VDDQ level.
Boosting the memory voltage can improve System
memory performance tuning.
PLEASE KEEP IN MIND THAT MEMORY VOLTAGE
ADJUSTMENT IS THE MOST DANGEROUS VOLTAGE
RAIL TO ADJUST AS IT CAN DESTROY NOT ONLY
THE MEMORY BUT ALSO THE CPU AND CAN
POTENTIALLY DAMAGE THE MOTHERBOARD.
 

Rifter

Lifer
Oct 9, 1999
11,522
751
126
I don't think it is that big of a deal these days because DDR3 is so fast that only benchmark queens care about overclocking RAM a huge amount.

Have you seen the Llano benchmarks, the ram speed has a huge impact on performance.

This might have been true in the past but not for Llano
 

Zap

Elite Member
Oct 13, 1999
22,377
7
81
:oops:

I was just thinking CPU performance. You guys are absolutely right in regards to the IGP.

I wonder how many more peeps will pile in to join the three that already corrected me. ^_^
 

Rifter

Lifer
Oct 9, 1999
11,522
751
126
:oops:

I was just thinking CPU performance. You guys are absolutely right in regards to the IGP.

I wonder how many more peeps will pile in to join the three that already corrected me. ^_^

hey its not everyday we can give a mod a hard time! :)
 

Nemesis 1

Lifer
Dec 30, 2006
11,366
2
0
Ya the memory used in this preview was The biggest issue I had with the preview . AMds APU using ddr3 1600 benefits greatly. In performance. Well at least I consider it to be big improvements. It would seem AMD choose to use DDR3 1300 because it would give better power usage .
Were can I buy the laptop that AT used in this review or was it a preview . If its a review I would like to check out the specs on retail notebook. Any one have a link to were I can buy one?

For a review this was a strange one . Intels notebooks lacked specs . This was anything but normal review thats done here by AT .
 
Last edited:

Vette73

Lifer
Jul 5, 2000
21,503
9
0
:oops:

I was just thinking CPU performance. You guys are absolutely right in regards to the IGP.

I wonder how many more peeps will pile in to join the three that already corrected me. ^_^


SOMEONE WAS WRONG ON THE INTERNET!!!

GET HIM!!!

torch-and-pitchfork.jpg
 

pantsaregood

Senior member
Feb 13, 2011
993
37
91
Since it uses DDR3 I would say no.

The DDR2 memory controlled was replaced or upgraded tot he new DDR3 memory controller

AM3 CPUs had both DDR2 and DDR3 memory controllers on board. I very seriously doubt there's a DDR2 controller on board, since none of the Llano sockets seem to use DDR2.

Also, overvolting the memory controller on Llano probably isn't very necessary at the moment. Running DDR3 2133 shouldn't take too much more voltage than DDR3 1866, and as far as I know Llano runs DDR3 1866 by default. I also don't know of any 1.5v RAM that runs at speeds above DDR3 2133 at stock.

Llano with decent cooling and DDR3 2133 will probably make a killer combo, honestly. Something as cheap as a Hyper 212+ can generally take a CPU to its practical limits, as far as overclocking is concerned.

I wouldn't be surprised if most Llano-based CPUs can run at 4.0+ GHz. It wasn't that uncommon for 45nm K10s to hit 4.0 GHz, so I can definitely see them managing it with a die shrink. The GPU can hopefully be overclocked as well.
 

Zap

Elite Member
Oct 13, 1999
22,377
7
81
Here we go! Coupon code EMCKDJC43 this weekend nets you 8GB Mushkin Redline DDR3-2133 for $100 shipped. This is 1.65v CAS 9 which is pretty darn good for those speeds, especially since I've seen high speed RAM at 1833MHz or up that is CAS 11.

Wonder if we'll see RAM marketed for Llano?