Using DIMMs Bigger than Mem Controller Max Size

[RKMason]

Hi, I've been looking for the answer to my question and so far no joy, so I thought I would throw it out here for all of you smart guys to consider.

Question: Will DDR3 DIMMs that are bigger than the max size supported by the memory controller still work OK even though you will only use a fraction of the DIMMs true capacity? In my case, I have an older ASUS mobo using the Intel X38 chipset. The spec'd max size DIMM you can use with this chipset is 2GB which means maximum memory is 8GB (4 x 2GB DIMMs). The chipset will support DDR3 DIMMs, but 2GB DDR3 DIMMs are now near-obsolete and more expensive than 4GB DDR3 DIMMs. I would like to use 4GB DIMMs on this mobo even if I only get to use 1/2 the true memory cacpacity. I'll be able to migrate these 4GB DDR3 DIMMs to a newer mobo in the future and use the true memory capacity.

Will they work?

 

[Harvey]

It's worth trying. Many, but not all, older motherboards support more RAM than originally spec'd because the larger sized RAM sticks were not available when the specs for those machines were originally created.

Intel's spec for the X38 chipset states:

Max Memory Size (dependent on memory type) 8 GB

DDR3 RAM comes with various voltage requirements from 1.35 v, 1.50 volts, 1.65 volts and 1.85 volts. Be sure to select RAM that matches the voltage your machine can provide.

Also, timing info is as important as the voltage. Check your motherboard manufacturer's site and the memory selector guides on various manufacturers' sites to find models they spec for your machine. That will give you the voltage and timing info you need, even if they don't spec 2 x 4 GB modules. You can also search Google for your motherboard model number and "RAM" or "memory" to find this info.

In any case, you probably won't damage the RAM if you try it, as long as you don't over-voltage or overclock it.

Here's a list of Newegg's 2 x 4 GB DDR3 RAM, arranged low to high prices. You can further modify the list to show only those with the voltage and timing specs you need.

Hope that helps. Good luck.

 

[tcsenter]

Most likely, no, but it depends on what is the actual limitation. There have been cases of arbitrarily defined "supported" limits specified for system memory. i.e. this is what we are defining as the limit (that we will support), but is actually not technically the limit. Intel is usually pretty good about disclosing real limits. System BIOS will also need to know what to do with modules larger than 2GB, which will use higher-capacity DRAM ICs, or at least not choke on them.

 

[RKMason]

Good info, Thx.

A spec for my mobo shows "4 x DIMM 240-pin ( 1.5 V )" as the memory requirement. I'll give it a try using a pair of 4GB DDR3 DIMMs and see if I end up with a working system with 4GB total memory (or something else maybe).

 

[Harvey]

If you already own 2 x 2 GB sticks, see if you can find two more of the same, and you'll have matched sticks. If you go this route, you must use RAM with the same speed and voltage specs.

If you can't find the same RAM, at least, you can find the speed and timing of that model, which will guide you in choosing your new RAM.

Here's Newegg's list for 2 x 2 GB 1.5 volt RAM.

Here's the same list for 2 x 4 GB sticks I posted, earlier, narrowed to 1.5 volt sticks.

You'll save around $10 if you can find 2 x 2 GB sticks that will work with your current RAM.

 

[spacejamz]

If you already own 2 x 2 GB sticks, see if you can find two more of the same, and you'll have matched sticks. If you go this route, you must use RAM with the same speed and voltage specs.

I was running two 8GB G.skill DDR 3 1600 CAS 10 sticks and just popped in two more 8GB Patriot 1866 CAS9 sticks today in on my Asrock X97 Extreme 6 board...running at the slower 1600 CAS 10 speeds but no issues so far...

 

[VirtualLarry]

It depends on the "density" of the chips used on the DIMMs too.

For example, there's a lot of uber-cheap DDR2 on ebay, and you'll noticed that most of them specify "high density" "for AMD systems only". On Intel rigs, you don't simply get half the size, in fact, they aren't even recognized at all!

 

[Harvey]

If you already own 2 x 2 GB sticks, see if you can find two more of the same, and you'll have matched sticks. If you go this route, you must use RAM with the same speed and voltage specs.

I was running two 8GB G.skill DDR 3 1600 CAS 10 sticks and just popped in two more 8GB Patriot 1866 CAS9 sticks today in on my Asrock X97 Extreme 6 board...running at the slower 1600 CAS 10 speeds but no issues so far...

If RAM that is mis-matched for speed works, it will typically default to the slower speed, but it doesn't always work. Matched RAM gives you a better chance of success.

The Intel X38 chipset on OP's motherboard doesn't support more than 8 GB. He can go with 2 x 4 GB and sell the 2 x 2 GB sticks to a friend for a very friendly price, and both of them will come out ahead.

 

[Phynaz]

It's worth trying. Many, but not all, older motherboards support more RAM than originally spec'd because the larger sized RAM sticks were not available when the specs for those machines were originally created.

Intel's spec for the X38 chipset states:



DDR3 RAM comes with various voltage requirements from 1.35 v, 1.50 volts, 1.65 volts and 1.85 volts. Be sure to select RAM that matches the voltage your machine can provide.

Also, timing info is as important as the voltage. Check your motherboard manufacturer's site and the memory selector guides on various manufacturers' sites to find models they spec for your machine. That will give you the voltage and timing info you need, even if they don't spec 2 x 4 GB modules. You can also search Google for your motherboard model number and "RAM" or "memory" to find this info.

In any case, you probably won't damage the RAM if you try it, as long as you don't over-voltage or overclock it.

Here's a list of Newegg's 2 x 4 GB DDR3 RAM, arranged low to high prices. You can further modify the list to show only those with the voltage and timing specs you need.

Hope that helps. Good luck.

Wow, the price of memory has crashed over the last few months.

 

[StrangerGuy]

YMMV on compatibility but if you want 2 x 4 GB DDR3 for Core 2 chipsets it at least has to be double-sided 16 x 256MB chip DIMMs. The Kingston 1.5V ones work like a charm on my old G41 board. This particular model - http://www.kingston.com/dataSheets/KVR1333D3N9_4G.pdf

The much more common 8 x 512MB ones will not work.

 

[Oyeve]

Dunno. but last week I installed 16gb ddr2 (4x4) on my intel p35 based and the bios and system sees all 16gb, and its old ddr2 spec. I imaging your more recent system should work. The specs for my system said 4x2 for ddr2 for a total of 8gb. I took a chance (and the companies dime) and got 4 4gb sticks and all is good.

 

[razel]

Max mem for x38 chipset is 16GB. We have a few older Intel chipset Core2 workstations here that don't have a max mem specifications, but are running more than 8GB of RAM. 12GB (2 x 4GB, 2 x 8GB) actually. I have great luck using max RAM stated by Intel than what was spec'd by the manufacturer. Yes, manufacturers can artificially limit the amount of RAM, but there is often no good reason to do so.

What we had to watch for was how the pairs of memory were installed. This was during the time of flex-memory channel. The x38 is from this era. Your manual will state it if it does so.

 

[VirtualLarry]

Dunno. but last week I installed 16gb ddr2 (4x4) on my intel p35 based and the bios and system sees all 16gb, and its old ddr2 spec. I imaging your more recent system should work. The specs for my system said 4x2 for ddr2 for a total of 8gb. I took a chance (and the companies dime) and got 4 4gb sticks and all is good.

Interesting. I thought that the P35 chipset wasn't specced that high. Does it pass Memtest, and does Windows report any unusable memory?