Memory not as fast as advertised

[slave1]

Hi all,

I just rebuilt my comp this weekend and for the new core component I purchased:

-AMD Phenom II x6 1090T 3.2
-Asus M5A97 EVO
-Sapphire RAD 6870HT
-Corsair Vengeance DDR 3 8GB (2x4GB) full produc ID: CMZ8GX3M2A1866C9

Now on the back of the mobo's box the memory specs are: 4xDIMM, Max 32GB, DDR3 2133(O.C)/1866/1800/1600/1333/1066 MHZ

In CPU-Z, under SPD if I look at Channel 2 and 4 they both state the same:



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Since it is dual channel I would assume that with both module my actual speed is at 1333mhz.

How could this be?...more importantly how can I make it go up to 1866mhz?

Thanks,

Phil

 

[jaquith]

The Default SPD is indeed DDR3-1333 with 1090T, and even with Zambezi FX-series the default is the highest JEDEC up to DDR3-1866 and XMP is not a JEDEC standard it's Intel's version of 'SPD'.

Problem, in order to set the RAM Frequency >DDR3-1333 even on the 6-core AM3 you'll need to both manually set DRAM Frequency AND the FSB 240MHz (OC) or CPU-NB Frequency to 2400MHz or use ASUS's DOCP.

RAM DDR3-1866 9-10-9-27-2T @ 1.50v

BIOS:
AI Overclock Tuner -> DOCP
Memory Frequency -> DDR3-1866MHz ; this speed 'should' be available if not then FSB is required**
DRAM Timing Control /Enter
DRAM CAS -> 9
DRAM RAS -> 10
DRAM RAS PRE -> 9
DRAM RAS ACT -> 27
-
DRAM Command Rate -> 2T

Save & Exit = Yes

Now since the kit is 1.50v the DRAM Voltage and CPU-NB Voltage are 'typically' not required. ** IF DDR3-1866MHz is not available in the menu then I'll post the alternative method of FSB (OC).

 

[slave1]

Thanks Jaquith, I will give your solution a whirl later on today and post back the results.

Thanks !

 

[jaquith]

Good let me know. BTW - I edited the two paragraphs above for better clarity.

 

[slave1]

Well that was easier than I thought, switching ti DOCP I then click on Profiles and there was already a 1866 DDR3 9-10-9-27, I only had to switch the command rate to 2T.

Ok so here are some screens, first one is for the SPD tab in CPU-Z, before and after are identical so I just uploaded the "after"



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***

Second screen is for the Memory tab before making the changes



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***

Final one is for the Memory tab after making the changes



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***

Your thoughts?

Thanks,

Phil

 

[jaquith]

My thoughts are you're good! The RAM is running 1878.4MHz (2 * 939.2) {DDR3 = Double Data Rate rev 3}; the variance is the FSB which normally bounces up and down slightly due to CPU load.

IMO - I always set the CAS Timings (CAS-TRCD-TRP-TRAS-CMD) manually, to avoid BIOS goof-ups. However, both the Frequency and CAS look correct nonetheless.

 

[slave1]

Nice!

It's always good to have what I actually paid for

So I guess that if my system ever becomes unstable I should just reset the DOCP back to it's original settings then?

 

[jaquith]

DOCP by itself won't (shouldn't) cause a problem. At some point if you decide to OC the CPU then the idea is essentially the same, but AI Overclock Tuner -> Manual, OC Tuner, CPU Ratio, CPU Voltage, DRAM Frequency, etc.

IMO I would save the Profile you have now; see page 3-27 of the manual.

To 'reset' the best place to start is 'Load Optimized Defaults'; see page 3-28. Worst case if things get to the point of 'Post Failure' use the Clear CMOS procedure; see page 2-16.

Good Luck!

 

[slave1]

It's all gold Jacquith, thanks so much for your help today.

I am not the OC type, it's the first time I've OC'd anything, still I will keep the post in my archives just in case.

Thanks again !!!

Phil