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CL7 or CL9 Corsair 4gb XMS3 1600Mhz

Last response: in Memory
July 7, 2011 6:14:51 PM

I know the question of CL9 vs CL7 has been asked many times before but I dont feel that usual end result of the discussion that "It wont be noticible" is an accurate representation of CL7 performance.

I underclock the memory in my system to 1440Mhz so I can get the most out of my i7 920 due to the fixed CPU multiplier.

My current 9gb's (3x1gb 3x2gb) of previous series corsair XMS3 1600Mhz 9-9-9-24 is running at 1440Mhz 8-8-7-23.

I dont plan on upgrading my chip till the die shrink of the LGA 2011's come out so the RAM is going to be underclocked like it is for 3 years or so, plus DDR4 doesnt come out till 2015 plus then add the waiting for the biggger sticks to become reasonable in price so I want to make the right choice now.

I'm going to buy 24gb's of RAM but if I get the CL9 I will split it into two 12gb purchases a few months apart but if I buy the CL7 I need to do it all at once since I
dont want to mix the timings.

In the end the price difference between 24gbs of the CL9 compared to the CL7 is about $118 AUD.

I tend to try a lot of different stuff on my computer but I'm not folding, photoshop or video processing/rendering ect. and I wont be in the foreseeable future.

But before you tell me I dont need 24gb's I'm going to run two 10 person minecraft servers (6gb each) and a ramdisk.

The simple question is will there be any benefit of underclocked CL7 with tighter timings compared to underclocked CL9 with tighter timings?

I mean in anything, absolutely anything apart from benchmarks of course?

a c 347 } Memory
July 7, 2011 7:26:55 PM

First, I'm not a fan of XMS3 RAM.

Next, 6x4GB is a little tricky and mixing (2) sets is no guarantee that they'll run as you've described.

The few that I feel comfortable recommending together as 3x4GB + 3x4GB:
1. Mushkin Enhanced Blackline 12GB (3 x 4GB) DDR3 1600 Model 998776
2. CORSAIR Vengeance 12GB (3 x 4GB) DDR3 1600 Model CMZ12GX3M3A1600C9
3. G.SKILL Ripjaws Series 12GB (3 x 4GB) DDR3 1600 Model F3-12800CL8T-12GBRM

Side-By-Side ->|20-226-100^20-226-100-TS%2C20-233-146^20-233-146-TS%2C20-231-406^20-231-406-TS

So if you're taking about 1600 CAS 7 the sets that work are very expensive and the performance difference doen't justify the price. Further, 7-8-7-24 vs 8-8-8-24 are negligible and 9-9-9-24 with a good IC can beat them all. I find the 7-8-7-24 don't OC very well and non-JEDEC CAS, loose timings, are for the birds.

Comparisons & Considerations, 1600 MHz $250 {7-8-7-24} F3-12800CL7T-12GBRM versus {9-9-9-24} 998776 $120 is beyond foolish to consider, and all too often oddball CAS Timings like 7-8-7-24 end-up running at 8-8-8-24 to keep them stable.

Therefore, get the Mushkin Enhanced Blackline 998776 and you may need to Disable Memory Protection to see all 24GB.

Q - What BCLK are you running?

Theoretical Frequency to CAS; stressing the 'Theoretical':

Comparison Module #1: Mushkin Redline 996805 6-8-6-24 1600MHz
Comparison Module #2: G.Skill Pi Series 7-8-7-24 1600MHz
Comparison Module #3: Mushkin 998687 8-9-8-24 1866MHz
Comparison Module #4: Corsair Dominator TR3X6G1600C8D 8-8-8-24 1600MHz
Comparison Module #5: Kingston HyperX T1 9-9-9-27 1600MHz
Comparison Module #6: Mushkin Blackline 998677B 7-7-7-20 1333MHz
Comparison Module #7: Patriot Viper II Sector 7 9-9-9-27 1800MHz


Overclock 1800 MHz:
July 7, 2011 7:42:47 PM

CL = Cas Latency, so yes CAS

First like I said I'm underclocking not overclocking the RAM.

My base clock is 180 with 20x cpu and 8x RAM multiplier. i7 920 c0 @3.6Ghz 1.4v VTT 1.3v Vcore 1.66v dRAM

I dont have to mix RAM.

I would only be mixing RAM if I bought the CL9 in two sets even then the mixing would be with my current ram which is the exact same except for the year (dec 2008).
and the price like i said its only $120 between 24gb's of CL7 and CL9.

If I bought the CL7 it would definitely be all 24gb's at once and I can do the same for the CL9, it was only an idea.

I'm sticking with corsair since its what I've got, it's relatively cheap and I have many other things I need to Upgrade.

My system was the low end of performance built by the local computer shop back in dec 2008 just before I learnt how to build pcs myself so it leaves a lot to be desired.

I need the RAM for the servers but it also looks like it will be another $1200 to watercool to get the noise down to 13dba.

The exact RAM I'm looking at:
Related resources
a c 347 } Memory
July 7, 2011 8:33:00 PM

Let me further define 'Mixing', yes the obvious mix-matching of Frequency, CAS & Voltage, but also creating pseudo-sets buying 3, 6, or whatever individual sticks are in no way guaranteed to work as a 'Set' and certainly not at 'Rated' from your example of 1x4GB + 1x4GB + 1x4GB + 1x4GB + 1x4GB + 1x4GB; I'd love it if it were so. If you choose to run them at 'SPD' or 1066 MHz they 'should' or 'might' work but still no guarantees.

I too often see SETS of 2 2x4GB and 2 3x4GB either not working at all or best not at Rated. Yes, I can see you said 1440 it's not 1066 MHz. Individual sticks, for the most part, are the low bin or worst of the production so they often cannot be sold as sets. The XMS3 are considerably more problematic than their Dominator and Vengeance counter-parts - reason poorer quality IC and lower bin.

Q - If you have a GA MOBO for example why not use a Memory Multiplier of 9? 9*180= 1620MHz. If your mix is good then there's a ZERO % chance 1620 won't work. I mean BCLK 180 MHz the BCLK variance alone makes it less than negligible. I can run my Corsair Dominator 1600 MHz at 1800 MHz 7/24/365; quality IC & perfectly matched ;) 

Bad Choices:
Guaranteed to fail with 24GB -> Corsair CMX4GX3M1A1600C7 4GB (1x4GB) DDR3 ; I'd bet real money.
Ditto with 24GB -> Corsair CMX4GX3M1A1600C9 4GB (1x4GB) DDR3

There's nothing low-end about a i7-920.

If you're going to stick with Corsair then get 2 set of CMZ12GX3M3A1600C9 for 24GB.

Some people need to find this out the hard way...others listen.
July 7, 2011 9:04:46 PM

okay that makes sense.

strange that the local computer guy I always talk to never mentioned anything about it. In fact he recommended single sticks. Guess hes just been lucky.

As much as I understand the do not mix it is going to cost the same price as the CL7 for 2 CL9 12gb kits.

I would never buy vengeance sticks since I think they are the ugliest things on the face of the earth. Is there any benefit of 1.5v?(not OC'ing remember) .

My only option if I stick with Corsair is two Dominator 1600Mhz CL9 3x4gb kit:

the other two options (yes this site has the only decently priced RAM I can find)

Kingston 3x4gb 1600Mhz 9-9-9-27 1.65v kit

G.Skill Sniper 3x4gb 1600Mhz 9-9-9-24 2.5v kit

I dont even know if the G.skill will work with my motherboard.

My board is a Gigabyte GA-EX58-DS4 so I don't have a x9 multiplier.

I never said just low-end. I said low-end of performance which would have been better written as low high-end.

the build back then was a GTX260, 3gb's of xms3 1600 cl9, i7 920 c0, ga-ex58-ds4 and I still had a fan on the CPU (now h70 I've just noticed the helix tubes resonate with my case).

thats why I call it low high-end.

I have been looking at a G1.guerrilla since I have a asus xonar d2x and don't need the sound chip on the G1.Sniper.

But I still have water cooling to do $1200 and I want a new Razer Mamba $200 and that board is another $400

there is an eventual limit sadly.

Best solution

a c 347 } Memory
July 7, 2011 9:36:47 PM

Then get the Corsair Dominator CMP12GX3M3A1600C9, 6x4GB will be toasty warm and a RAM Fan is a good idea.

Regarding the OC, I would Disable HT (CPU Multi Threading), raise BCLK, lower the CPU Clock Ratio and use a Memory Multiplier -> 8. If your Apps benefit from Hyper-Threading then use it otherwise it adds a lot of heat with no benefits.

Once you get those Kits, QPI/VTT Voltage -> 1.35v and DRAM -> 1.66~1.68v, set the DRAM Timing Selectable (SPD) -> Quick and enter your CAS Timings, and Command Rate -> 2. Don't use XMP.
July 7, 2011 9:42:35 PM

Best answer selected by jtmzac.