Computer won't post with four ram sticks.

[detz]

I'm all excited to get 16GB ram and the computer won't post with four sticks inserted. I purchased the exact same ram and they work in every combination in the first slots but if I put all four in....nothing. Any thoughts?

[garycase]

That's not as unusual as you might think.  With unbuffered RAM, the load on the control and data buses is VERY high when you install more than one module per channel (as you've done) ... and the degraded waveform can sometimes result in either a significant number of random errors, or even (as in your case) a complete failure.

 

You can try a couple of things to mitigate this:

 

(1)  Install just 2 modules; then boot to the BIOS and change the memory timing to add an extra latency cycle (this gives the bus signals more time to "settle").  Then shut down and see if it will now work with 4 modules.

 

If not ...

 

(2)  With 2 modules installed, boot to the BIOS and slightly increase the memory voltage.    In fact, be  sure you're not using modules that require a higher-than-standard voltage ... if so, increase the voltage even more -- to slightly above the specified voltage for those modules.    Then shut down and see if it will now work with 4 modules.

 

If not ...

 

(3)  With 2 modules installed, boot to the BIOS and change the memory frequency to a slower clock speed.

 

If the combination of the above changes still won't let your memory post; then the modules you have may simply not be compatible with your board.

 

 

[detz]

So, good and bad news. :-)

 

I quickly read something online while it was down and it set to change my settings to manual instead of auto so I set them to 9/9/9/24, which of those numbers should I bump up? Auto put them at 7/7/7/20 which is lower than what they say on them.

 

I also lowered the voltage closet to 1.5v like is says on the chips but maybe that wasn't right either?

 

I don't think it's the chips since the two new ones are in there now working fine. It appears that only when they're together that there is an issue.

 

I try these steps out later, thanks!

[garycase]

You don't want to LOWER the voltage -- you want to slightly increase it.  Are you sure your modules are all designed for the same voltage?    If not, that likely explains your problem ... and the fix for that is to get modules with the same specifications.

 

The latency settings should be fine at 9 cycles ... that's a couple extra cycles, which is normally all you'd need.

 

I'd bump the voltage a bit -- if they're 1.5v modules, set it to 1.6v.    And I'd also decrease the clock frequency.

 

[detz]

besides when they were manufactured they're the exact same modules, same size, brand, timings, etc.

 

Nothing works, it's not the ram or the slots as I've tried every combination, it's just that it doesn't like four sticks together. I read something about being two sided ram, I don't know enough to know why this matters but these sticks are all two sided, would that make a difference? It appears I'll have to get four new sticks, is there a way to know for sure what will work before buying?

 

When I search crucial for my motherboard I see lots of options. Is this pretty reliable or do they just check the board specs and compare the ram?

[dikkiedirk]

What motherboard and what RAM are we talking about.

 

The user manual might help.

 

[garycase]

If these are all 2-side modules than you have a VERY high electrical load on the bus when you insert 4 modules.  Count the number of memory chips on each module -- if there are 16 on each side, then there are 32 'loads"/module ... or a total of 128 loads on the bus with 4 modules.    It's not at all surprising that the system won't support that much of a load.    You need a different set of modules or, better yet (if the system supports them) larger modules so you can just use 2 modules to get the amount of memory you want.    With unbuffered memory systems, it's always best to only install one module per channel => so if your motherboard supports 8GB modules, you should get two of them instead of using 4 4GB modules.

 

 

[garycase]

... what's the motherboard make/model?

 

[detz]

ASRock - H61iCafe

 

Looks like I'm stuck, it appears (which is odd) that they put four slots but didn't really intend for anyone to install four modules.

[c3]

If you follow the recommendations above you will probably get 4 DIMMs to work.

 

It would help if you mentioned what DIMMs you have.

 

1) Boot with (2) DIMMs.

2) Detune memory - add cycles, lower memory speed, and raise voltage to offset the impact of adding more components.

 

Examples

- add cycles, go from 7/7/7/20 to 9/9/9/24

- lower memory speed - go from 1333 to 1066

- raise voltage - go from 1.5v to 1.6v

 

These changes would be based on a DIMM which normally runs at DDR3 1333 7/7/7/24 1.5v. Not changing the DIMM to a different part, just BIOS changes.

 

 

[JorgeB]

The H61 chipset only supports one double-sided DIMM per memory-channel and therefore is limited to 16 GB instead of the 32 GB like the others support.On H61-based motherboards with four DIMM slots, only four single-sided DIMMs can be installed.

 

From Wikipedia

[garycase]

Johnnie's post reinforces what I noted above => if you're using double-sided modules there's simply too much of a load for the system to work with 4 modules.    You either need to use single-sided modules; or only use two modules.

 

[garycase]

Note that while Johnnie's quote is from Wikipedia, it's also directly noted on AsRock's specfications page for this motherboard;

http://www.asrock.com/mb/Intel/H61iCafe/?cat=Specifications

 

i.e. "... **This motherboard supports two double-sided or four single-sided DIMMs. Therefore, if you install four DDR3 DIMMs, you can only adopt four single-sided DIMMs."

 

AsRock's specifications page also indicates a maximum of 16GB of RAM, but is silent on whether or not it will support 8GB modules.  Crucial, however (who almost always has it right), does NOT show any 8GB modules for this board, so it most likely does NOT support 8gB modules.  So if you want 16GB you'll need 4 single-sided 4GB modules.    The safest way to get that would be to buy a 16GB kit from Crucial from their memory selector for this board.

 

 

[JorgeB]

Note that this is a chipset limitation, all H61 based boards support only 1 dimm per channel, this is why 99% of these boards only have 2 dimm slots, same is true for other entry level chipsets, e.g., H81 and H110.

 

It *should* work with 2 x 8GB dimms, as long as they are installed in different channels (same color slots).

[garycase]

I suspect it's a function of the bus loading -- i.e.they'll support 2 modules per channel IF they are single-sided modules; but only one module/channel if they're double-sided.    At least that's what AsRock's specs say for the board.

 

Personally, I NEVER install more than one module per channel on unbuffered memory systems.

 

[clowrym]

I ahve this same issue with my  Supermicro - X7DB8-X, can only install 16GB ram, rather than the 32GB its supposed to support!!

[garycase]

It's not at all unusual to have issues with unbuffered memory subsystems when you install more than one module per channel -- ESPECIALLY if they are double-sided modules.    The steps I outlined earlier -- bumping the voltage; increasing the latency; and reducing the clock frequency can help, but the bottom line is that with the very high loads that these modules place on the bus the signaling waveforms are significantly degraded and can sometimes simply not be useable.

 

The BEST solution by far is to use buffered modules => unfortunately these aren't supported by desktop chipsets; and even by some lower end server chipsets.    With buffered modules there's one load per MODULE instead of one load per CHIP (16-36 loads per module) ... so there's virtually no waveform degradation of any consequence no matter how many modules you use.  With Intel chipsets, however, that means you have to use an E5 series Xeon system.

 

[clowrym]

I'm using buffered, but i believe this is my issue, just haven't had a chance to try it out

 

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