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RAM not running at 1600 - motherboard should allow it

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April 30, 2012 8:36:02 AM

Hello,

First off, I have tried to the best of my abilities to solve this issue but after a day of trying I'm resorting to these forums. I helped a friend build a PC yesterday and during the process I realized that even though I have 1600 mhz RAM on my PC, that doesn't necessarily mean it's running at that speed. After learning about CPU-z, I found that was my case. I've read through the forums here and tried to solve it on my own but have had no luck. I know details are helpful so I'll include as much as I knowledgeably can. Here's where it stands:

Originally built the PC a couple of years ago.
Motherboard: Gigabyte GA-P55A-UD3 http://www.gigabyte.com/products/product-page.aspx?pid=...
Processor: i5 750
RAM: 4gb (2 sticks of 2GB) 1600mhz (pic below)

I just bought another 8 gigs (2 sticks of 4gb), which are also 1600mhz and installed them.
Pic of RAM:
Pic of RAM now installed:

Now some pics that will show the problem and hopefully provide additional info:
CPU-z pics:






BIOS pics:





So how in the world can I get these to run at the 1600 mhz they're supposed to? I tried monkeying with the motherboard software but this tinkering is still pretty new to me. I believe I was successful at updating the BIOS. I would greatly appreciate any help.

EDIT: I am aware of how they should show up as 800mhz (not 1600) in CPU-z.
a b V Motherboard
April 30, 2012 11:49:36 AM

That board can run 1600 MHz RAM. With an i7 860 or i7 870, you'll have a memory multiplier you can use to reach 1600 MHz. With an i5 750 (or any i3 or i5 Clarkdale CPU) the highest you can reach at stock is 1333 MHz. But if you OC your CPU and memory the board will support the faster frequencies
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a c 716 V Motherboard
April 30, 2012 12:43:30 PM

Regarding the CPU limits stated above that's correct, the limit to stability of the i5-750 is DDR-1333 @ stock BCLK; the barrier is the stock CPU frequency of 2.66GHz as shown below.

The problem on the other hand here is that you are mix-matching RAM with clearly different JEDEC 'SPD' @ Ratings. If it were 'me' I would leave it alone, or at best DDR3-1333 9-9-9-24 @ 1.50v~1.55v and set manually. My feeling is OC the BCLK with an unmatched sets is an accident and by that I mean errors waiting to happen.

Manually:
System Multiplier -> 10 ; 10*133.33MHz (BCLK) = 1333MHz
DRAM Timing Selectable -> Manual or Quick depending on your BIOS
/CAS Timings 9-9-9-24 (CAS-TRCD-TRP-TRAS)
DRAM Voltage -> 1.55v ; (2) sets

Otherwise to achieve DDR3-1600 you'll need to increase the BCLK = 160MHz, Decrease the CPU Multiplier = 17, and the Memory Multiplier = 10, DRAM Voltage = 1.65v~1.68v, and try the (CAS-TRCD-TRP-TRAS) of 9-9-9-27.

In any case create a bootbale CD/DVD of Memtest (ISO/zip) and run for at leat 4-pass or more; link - http://www.memtest.org/


Example from ASUS, but the same CPU limits apply.
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April 30, 2012 1:27:25 PM

Use XMP profiles...
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April 30, 2012 4:06:36 PM

Thanks for the replies. Unfortunately most of what was said is way over my head. What's going to be easier for me, a complete novice, to do? I've never OC'd a computer.

1. Remove the old 4gb and get the 8gb to run at 1600?

or

2. Get all 12gb to run at 1333

Overall intent - this is for a gaming PC.

Regarding XMP Profiles - that sounds familiar. How do I get to that? I think I saw it in the BIOS once but it's no longer there.
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a c 716 V Motherboard
April 30, 2012 4:13:24 PM

8GB is the ideal minimum for Gaming, and DDR3-1333 vs DDR3-1600 might add a few FPS to the rendering. Example BF3 - 1GB OS and background (stuff) + 3.5GB Game + 3GB for optimized 'Video Shared RAM'.

XMP for DDR3-1600 on your CPU is an accident waiting to happen. The BCLK must be OC to 160MHz...etc as I've posted above.

So it's more a question of if you feel comfortable OC'ing than the Frequency of the RAM?
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April 30, 2012 4:42:28 PM

Specifically, it is for BF3. Are you saying I should stick with the 12 gb running at 1066? If the original 4gb is 1600 (the Oz stuff) then why is it only running at 1066 and not 1333?

To be honest, I have no idea what BCLK even means and that part's going over my head.

Also, I think at some point where I was monkeying around I had the 8gb (only installed) showing up at 700mhz in CPU-z.
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a b V Motherboard
April 30, 2012 5:01:47 PM

You have some crappy ram in slot 2. Take that type of ram out of it, if you want the system to perform better. XMP profiles are stored on the SPD chip and CPU-Z shows the recommended timings for that chip. The other ones don't match up. As someone else said, you are asking for problems doing that.
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April 30, 2012 5:28:34 PM

Okay, I took out the old 4gb. Here is what it now looks like. Am I doin it right? I think I created the XMP profile at some point yesterday but have no recollection of how I did it. If I set it to default, the memory goes to 1333.





I'm assuming from the previous answers that this should overall be a performance improvement. Yes/ no? If so, is there anything else I should tweak?
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a b V Motherboard
April 30, 2012 5:33:51 PM

the timings table under XMP on the screenshot of CPU-Z is a value that's stored on the RAM chip itself. If you enable XMP in BIOS, it should load those values and run them, or, alternately, you can manually set your ram timings and voltage to match that profile.
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April 30, 2012 5:57:22 PM

egilbe said:
the timings table under XMP on the screenshot of CPU-Z is a value that's stored on the RAM chip itself. If you enable XMP in BIOS, it should load those values and run them, or, alternately, you can manually set your ram timings and voltage to match that profile.


Okay I think I'm starting to understand this part. So because I had two types of RAM which have their own predefined XMP profiles, it did not show up in the BIOS. That is why you would have to manually define settings to apply to both types of RAM which, as jaquith was saying, would be not a good idea (and beyond my comprehension).

Now that I have just one type of RAM installed, the BIOS can load its XMP profile, thus optimizing its settings.

That being said, am I now better off with the new setup (8gb @ 700mhz DRAM) or going back to the old setup (12gb @ 533mhz DRAM) - with gaming in mind? I do other stuff like Photoshop but I'm guessing a game like BF3 is going to be more demanding anyways.

EDIT: If the CPU-z for the 8gb shows XMP-1600 at 800mhz, then why does the BIOS have it at 1400, and the new CPU-z shows it running at 700?
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a c 716 V Motherboard
April 30, 2012 6:44:58 PM

I don't even know where to start. On your CPU + DDR3-1600 + XMP it's a accident waiting to happen. The following assume (1) set of the XMP listed above. Especially IF XMP sets the DRAM Frequency to DDR3-1600 (800MHz in CPU-z) it will create an instability with the CPU IMC to properly handle that high frequency.

Choose one of the following, and the result will be a slightly OC CPU (2.72GHz) and the RAM running the DDR3-1600 properly. AGAIN, as above TEST with Memtest!

DDR3-1600 recommend changes:
BIOS:
CPU Clock Ratio -> 17 ; 2660/160=16.625 (17 rounded) ; 17*160MHz=2.72GHz
Base Clock(BCLK) Control -> Enabled
BCLK Frequency(Mhz) -> 160 (MHz)
Extreme Memory Profile (X.M.P.) -> Disabled
System Memory Multiplier -> 10 ; 10*160MHz = 1600MHz
DRAM Timing Selectable -> Quick
CAS Latency Time -> 9
tRCD -> 9
tRP -> 9
tRAS -> 27
Command Rate (CMD) -> 2 ; I recommend 2T with >DDR3-1333
DRAM Voltage -> 1.64v

Save & Exit = Yes

DDR3-1600 minimal changes:
BIOS:
CPU Clock Ratio -> 17 ; 2660/160=16.625 (17 rounded) ; 17*160MHz=2.72GHz
Base Clock(BCLK) Control -> Enabled
BCLK Frequency(Mhz) -> 160 (MHz)
Extreme Memory Profile (X.M.P.) -> Profile1

Save & Exit = Yes
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May 1, 2012 2:44:48 AM

jaquith said:
I don't even know where to start. On your CPU + DDR3-1600 + XMP it's a accident waiting to happen. The following assume (1) set of the XMP listed above. Especially IF XMP sets the DRAM Frequency to DDR3-1600 (800MHz in CPU-z) it will create an instability with the CPU IMC to properly handle that high frequency.

Choose one of the following, and the result will be a slightly OC CPU (2.72GHz) and the RAM running the DDR3-1600 properly. AGAIN, as above TEST with Memtest!

DDR3-1600 recommend changes:
BIOS:
CPU Clock Ratio -> 17 ; 2660/160=16.625 (17 rounded) ; 17*160MHz=2.72GHz
Base Clock(BCLK) Control -> Enabled
BCLK Frequency(Mhz) -> 160 (MHz)
Extreme Memory Profile (X.M.P.) -> Disabled
System Memory Multiplier -> 10 ; 10*160MHz = 1600MHz
DRAM Timing Selectable -> Quick
CAS Latency Time -> 9
tRCD -> 9
tRP -> 9
tRAS -> 27
Command Rate (CMD) -> 2 ; I recommend 2T with >DDR3-1333
DRAM Voltage -> 1.64v

Save & Exit = Yes

DDR3-1600 minimal changes:
BIOS:
CPU Clock Ratio -> 17 ; 2660/160=16.625 (17 rounded) ; 17*160MHz=2.72GHz
Base Clock(BCLK) Control -> Enabled
BCLK Frequency(Mhz) -> 160 (MHz)
Extreme Memory Profile (X.M.P.) -> Profile1

Save & Exit = Yes


Thanks jaquith. Most of that is over my head but I'll explore the BIOS and see if I can figure it out.

Are you saying I should do this with just the 8gb or with all 12?

This won't set like fry my motherboard will it? Or is that what the memtest is for? Never used that but I'll try and figure it out as well.
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a b V Motherboard
May 1, 2012 2:52:24 AM

You shouldn't mix RAMs with different CL and voltages. With different brands generally...

To Simplify, Base clock x Multiplier = Rated speed so you do the calculations yourself. To run 1600 MHz RAM you'll need to set the Base clock to 160 MHz and memory divider to 10x

Just drop CPU multiplier to 17x as suggested above.

Then put manually the rated tRCD, tRP,...... which is 9/9/9/24/2T then set manually the RAM voltage to 1.64V (or whatever labeled on the stick)

EDIT: Running Memtest86 just to make sure everything is stable.
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a b V Motherboard
May 1, 2012 2:54:31 AM

don't add that other ram. Memtest is to make sure that the 1's and 0's that computers use are actually being 1's when they are suppose to be 1's and 0's when they are suppose to be 0's. Unstable ram or a system can change the 0's to 1's and 1's to 0's causing all sorts of problems.

Besides, 8 gigs of ram is plenty.
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May 1, 2012 3:33:30 AM

Okay. Thank you for the explanations. Hopefully I won't screw this up and set my PC on fire. Fingers crossed and will report back soon. I'll keep the fire extinguisher nearby.
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a c 716 V Motherboard
May 1, 2012 12:09:09 PM

nwhisky said:
Thanks jaquith. Most of that is over my head but I'll explore the BIOS and see if I can figure it out.

Are you saying I should do this with just the 8gb or with all 12?

This won't set like fry my motherboard will it? Or is that what the memtest is for? Never used that but I'll try and figure it out as well.

I was ONLY referring to the the XMP 2x4GB set. Those settings are step by step in the BIOS and if you're not comfortable in the BIOS then leave 'as-is' with the 12GB.
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May 1, 2012 10:39:40 PM

Hi guys i have a question i have g.skill ram 2x2gb 800mhz (5.0,5,5,15,42) my question is can i damage my ram if i set it to 900mhz with a little increase in voltage that's all I'm asking will it be damaged or just unstable not looking for ram performance increase i need that frequency for cpu overclocking ,thanks!
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a c 716 V Motherboard
May 2, 2012 12:07:00 PM

The only thing that damages RAM is Voltage, and most RAM has a toleration of +0.2v or a tad more.
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a b V Motherboard
May 2, 2012 2:59:02 PM

mike911gt said:
Hi guys i have a question i have g.skill ram 2x2gb 800mhz (5.0,5,5,15,42) my question is can i damage my ram if i set it to 900mhz with a little increase in voltage that's all I'm asking will it be damaged or just unstable not looking for ram performance increase i need that frequency for cpu overclocking ,thanks!

And also depends what kind of RAM you do have, if it's a value RAM it's likely to get damaged immediately or not to boot.
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May 9, 2012 5:04:04 PM

Just to give a follow-up: I ended up just getting another stick of the same Kingston 8gb and letting not using the XMP. It all set at 1333 for all 16 then and I was told that 1600 vs 1333 didn't really yield a performance difference anyways. I did overclock the CPU just a bit with the motherboard software. Used the "green" setting with Gigabyte's green, yellow, red choices. Thanks for all the help everyone.
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May 9, 2012 5:04:24 PM

Best answer selected by nwhisky.
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a c 328 V Motherboard
May 10, 2012 12:24:50 AM

This topic has been closed by Nikorr
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