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6GB RAM is going slower than 4GB - any ideas?

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June 20, 2011 5:11:33 PM

Hey everyone. I've looked through the FAQ and posts and can't find an answer to the problem I'm having. Could anyone out there help me please? Basically I built a computer, using an ASUS P6X58D-E LGA 1366 Intel X58 with an Intel i7 920 CPU. This is a triple channel RAM configuration, so I used 3 x 2gb RAM Modules (Corsair TW3X4G1333C9A DDR3 XMS3 1333Mhz 9-9-9-24 1.50V).

The only problem is that the 3 RAM modules were from an 8GB kit 4 x 2gb, designed for dual-channel computers. I took 3 sticks out, and left the other in the previous computer (now gone). I've researched it, and the general consensus is that this RAM is ideal for triple-channel configurations, such as mine, and that the kits are marketed as dual-channel and triple-channel purely for selling bundles together. However, I might have misunderstood this greatly. My apologies if I have.

Whichever way, the computer recognizes the RAM fine if I put 1, 2 or 3 sticks in. However, the computer is far faster with just 2 sticks in as opposed to 3. I've put them in in different orders, and done various RAM tests, and they all test as being fine. So with the RAM seeming perfect, I'm thinking it's something else. Maybe something I need to configure in the BIOS? Or maybe they're hardwired to only work in dual mode?

I'm totally confused at this point. If anyone could shed any light on this it would be greatly, greatly appreciated!

Thanks everyone.

Lee
a c 347 } Memory
June 20, 2011 5:39:37 PM

Welcome to Tom's Forums! :) 

I'm very familiar with your MOBO, I have 10 of them, but I'm a little confused what you've done exactly. The way I'm reading this is that you have 2 kits of -> http://www.corsair.com/tw3x4g1333c9a.html

If that's the case then use all of the RAM in Dual Channel mode and DO NOT use the XMP setting in the BIOS, and instead set the DRAM Frequency -> DDR3-1333MHz and you can also set the CAS Timings of 9-9-9-24-2T and if necessary set the DRAM Voltage -> 1.50v~1.57v

X58 Configurations:

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June 20, 2011 5:59:57 PM

Thanks for your reply. I had 2 kits (i.e. 4 modules), but I left one in a previous computer, which has now gone. I now only have 3 modules, which are installed in the 1,3,5 slots (blue) on the motherboard.

Should I still follow your proceeding advice on setting frequency, timings and voltage? If so, are those settings easy to find/set in the bios?

Thanks.

Lee
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a b } Memory
June 20, 2011 6:02:46 PM

Yes, the dual- and triple- and quad-channel is mainly marketing fluff. However, there is the possibility of having one kit not working well with another kit.

Does the BIOS recognize the RAM as triple-channel? What programs are telling you that the 6GB config is slower?
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a c 347 } Memory
June 20, 2011 6:14:36 PM

By Default it's running them at 1066MHz, but the 'slower' comment concerns me that not all of the RAM is being used in Windows and the BIOS is turning-off 1-2 sticks.

First, check your Resource Manager, assume Win 7, the dead give-away is Hardware Reserved > 10~12MB and something like 2000~4000+ MB.



The dirt-simple thing to to is setting the DRAM Frequency, substitute DDR3-1333MHz for the DDR3-1600MHz example below:
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June 21, 2011 2:03:05 PM

Hey guys. The BIOS does recognize there being 6gb of RAM (shows on startup), and it also lists 6gb in CPU-Z. The computer is just generally slower in everything. e.g. it'll take 3 times longer to bootup. If I open up say a HD quicktime file, it'll take over a minute to open (instead of about 1 second when I'm just using 2 sticks).

And it doesn't matter which two sticks I use, I've tried every combination in every order (to see if I could find a bad one). No difference. The same with using 3 sticks - I've tried them in every order too, in case that affected anything. Same thing every time. It's irritating because theoretically, the system is happy and dandy with the 6gb, recognizes it with 0 error or issues. But practically, it's a whole different story.

I opened up the resource monitor and it all looked normal. It recognized all of the RAM and the Hardware Reserve amount was 9mb.

I went into the BIOS and the DRAM Frequency was at Auto. I've changed it to 1600MHz and 1333MHz and neither made a difference.

Should I set the CAS Timings and DRAM voltage to see if that does anything?

Thanks for all your help.

Lee
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a c 347 } Memory
June 21, 2011 2:44:54 PM

The BIOS or CPU-z 'seeing' the RAM means unfortunately nothing, you need to look at the Hardware Reserved {see above}. The BIOS can 'see' the RAM but if there's a problem shut it down to 'Windows'.

What you're describing sounds more like a bad DIMM slot than anything, and/or combination of kits. While I appreciate 'it theory' "there the same and therefore they should" work my observations is that's not always TRUE.

Tests:
1. Try 4-sticks in DIMM slots 1-4, see above.
2. Try 4-sticks in DIMM slots 1,2,3, and 5.

3. Try 3-stick 2,4, and 6 {may not boot}

Test 1 and 2 are to test known Dual Channel configurations, and Test 3 is an attempt to test ALL DIMM slots.

Setting the CAS and Voltage might help, but chances are it's set as 1.50v and CAS 9 already. If any Voltage has a chance it the QPI/DRAM Core Voltage -> 1.30v.

Let us know and Good Luck!
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a b } Memory
June 21, 2011 3:23:45 PM

I'm thinking it's either a bad slot on the board or a bad memory controller on the CPU. It may not be operating correctly when attempting triple-channel mode.

I'm hoping it's just the slot on the board (#5 according to the manual), and that putting the RAM into the black slots will allow it to boot up and perform at expected levels.
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June 21, 2011 5:49:56 PM

OK folks, I've done some more testing with the DIMM slots, putting the RAM sticks in different slots in varying quantities (2gb / 4gb / 6gb). The results are below. I've tried copying/pasting this table a bunch of ways but it keeps coming out bad. Basically the slots are 2-1-4-3-6-5 as per the mboard; 'X' denotes a RAM stick and '-' denotes an empty DIMM.

# RAM 2 1 4 3 6 5 RESULT
A 2GB - X - - - - 2GB - FAST
B 2GB - - - X - - 2GB - FAST
C 2GB - - - - - X 2GB - FAST
D 4GB - X - X - - 4GB - FAST
E 4GB X X - - - - 4GB - FAST
F 4GB - - - X - X 4GB - FAST
G 4GB - X - - - X 4GB - FAST
H 6GB - X - X - X 6GB - SLOW
I 6GB X - X - X - DOESN’T BOOT
J 6GB X X - X - - 6GB - SLOW
K 6GB X X - - - X 6GB - SLOW
L 6GB - X X X - - 6GB - SLOW
M 6GB - X - X X - 4GB - FAST
N 6GB X X X - - - 4GB - FAST

For test C, I used each RAM stick for slot 5 separately, to be double-certain that there wasn't some weird conflict between a RAM stick and DIMM Slot 5. It made no difference, fast with each of the 3 sticks.

So from that, it seems that the following statements are accurate:

1) Each and all of the RAM sticks are fine.
2) Each and all of the DIMM Slots are fine.

So it appears it's one of the 4 following scenarios:

SCENARIO 1 - Leaps-from-Shadows is right, it's a faulty memory controller on the CPU.

SCENARIO 2 - I've got some settings wrong in the BIOS, which is making it so that the following happens:
a) It recognizes the RAM fine.
b) It works at full speed with single / dual RAM setup.
c) It works slower with Triple-Mode (although supporting it).
- This to me seems really unlikely, since I hadn't ever touched the BIOS since building this machine myself (until trying to diagnose the problem of course).

SCENARIO 3 - The RAM is somehow hardwired to simply not work correctly in triple mode.

SCENARIO 4 - The BIOS somehow detects that the RAM is DUAL-MODE, and sets settings specific for that type of RAM, which don't work appropriately for Triple mode.

So that brings me to where I am now. Can anyone suggest any *perfect* settings to feed into the BIOS, overriding all the AUTO settings? Just in case the BIOS is somehow for some reason setting crappy auto settings. If I feed in ideal voltage, timing etc settings, that should completely rule that out I'm thinking.

On one last note, what is the memory controller? Is it hardware or firmware? Is it anything I can reset/flash/flush out/diagnose?

Thanks a bunch everyone, you're all being an amazing help.
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a b } Memory
June 21, 2011 6:43:48 PM

Wow, that's pretty darn thorough.

It appears as if any time it detects 2GB or 4GB it's fast, but if it detects 6GB it slows down. In some situations, with 6GB installed it only detects 4GB of it and operates at the fast speed.

Do you have the latest BIOS version for that board (0602)? There's a small possibility that might help your situation. If you already have it or you update it and it still doesn't work, then I suggest you contact Intel and RMA that CPU. Assuming it's within warranty, they might even advance-ship a new CPU to you first so you can test it.
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a c 347 } Memory
June 21, 2011 7:05:35 PM

SCENARIO 5 - Mixing Kits doesn't always work.

I assume this is where 4GB of 6GB was detected.
M 6GB - X - X X - 4GB - FAST
N 6GB X X X - - - 4GB - FAST

RAM running at SPD e.g. 1066 for X58 i7-9xx should work, period, if the RAM is in the correct DIMM slots edit: and the RAM is compatible.

The 'Tests' that I'd really like to see are the 4-stick.
1. Try 4-sticks in DIMM slots 1-4, see above.
2. Try 4-sticks in DIMM slots 1,2,3, and 5.

IMO - I seriously doubt it's the CPU, CPU IMC, DIMM Slots. Also, I would recommend that you get: 1. 3x4GB or 3x2GB kit for the X58, 2. Use 4x2GB from the prior sets and get a 2x2GB for the other MOBO. You've proven the DIMM slots function and that all channels work on the X58.

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a b } Memory
June 22, 2011 1:26:17 AM

Lee doesn't have four sticks to test.

And wouldn't testing determine which stick was the one that's not compatible? I see nothing at all in those numerous tests that show one particular stick not working with the others. No matter which of the three sticks are used, when 4GB is installed it detects 4GB and it's in 'fast' mode. Any time 6GB is detected, it goes into 'slow' mode. Plus, sometimes when 6GB is installed, only 4GB is actually detected by the BIOS but it's in 'fast' mode. This leads me to believe the CPU's IMC is not working correctly.

Again, if it was me, I'd be on the phone to Intel.
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June 22, 2011 5:47:08 PM

That's correct, unforunately I don't have four sticks to test. And I don't know anyone with a similar computer spec to me that I could either test my RAM in their machine, or vice-versa. Let alone switching CPU etc.

I've updated the BIOS to 0602, but it's still the same unfortunately. And yes - sorry I didn't clarify this in my earlier post - the M and N tests were where I put 6gb in but only 4gb was recognized. I assume that's because in that configuration, it only 'sees' 2 of the 3 sticks and is normal behaviour (i.e. it would behave the same way on every other machine with the same mboard as mine).

I recently searched on google, and some people have said on other forums that the CPU IMC either works or it doesn't i.e. if it detects the RAM, and the computer boots, it's working. But I think that what Leaps-from-Shadows mentioned in regards to something going wrong with triple configuration in the IMC sounds right. Just thought I throw that out there.

I think I might give Intel a call then - see what they say! I can imagine them blaming the mboard or RAM.

Let's see...
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a c 347 } Memory
June 22, 2011 6:56:14 PM

Q - Using the '3' sticks have you tried the MemOK button on the MOBO?

Just for 'kicks' try:
DRAM Voltage -> 1.60v {or closest value}.
QPI/DRAM Core Voltage -> 1.30v

Failure: {these are the typical 1.65v DDR3 settings}
DRAM Voltage -> 1.64v {or closest value}.
QPI/DRAM Core Voltage -> 1.35v

IMO - one of these -> http://www.newegg.com/Product/Productcompare.aspx?Submi...|20-226-100^20-226-100-TS%2C20-226-185^20-226-185-TS%2C20-145-321^20-145-321-TS%2C20-145-289^20-145-289-TS%2C20-145-224^20-145-224-TS

Damn good price/performance/capacity crazy cheap but good -> http://www.newegg.com/Product/Product.aspx?Item=N82E168...
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