Two kits of DDR4 RAM??

[BonzaiDuck]

I'm still "in progress" for building my Skylake.

When I originally ordered the parts, I thought that 16GB or 2x8GB of DDR4 (3200) RAM was all I would need.

Now I'm looking at this again, and wish I had another 8GB.

I may have read somewhere recently that you'd best buy a matched set of DDR4 "OC" RAM if you didn't want troubles with setting it up. They DO make 2x16GB kits in the model I would want, and it would cost me.

Can I expect my RAM to run according to the XMP spec profile if I add a kit of the same model for an additional 8GB or 2x4GB? Obviously, I could also get a 2x8GB kit and double the RAM.

 

[ch33zw1z]

If you can afford it, just get the same exact one. chances if you want another 8, another 8 after won't be far behind.

If you choose to get 4gb, get the closest thing you can to the same thing. checking timing's and voltages...

 

[BonzaiDuck]

I'm on top of that. For some previous rigs, you could mix G.SKILL kits of a different speed-spec, and run them at the lowest of the two. But the subtleties of RAM behavior beginning with DDR3 suggest a lot more caution. So as I have done this for socket-1155, "always pick the same suffix-code [like '-GTZ' or '-GBRL']," the same speed and timings. [With G.SKILL, this likely also means that the two kits have heatspreaders of the same design and color.]

The problem with larger configured memory: it could take days -- a week even -- to get the kits a clean bill of health within the RMA period with at least 500% coverage from HCI Memtest 64. Worse, there's the size of the page-file and the hyberfill.sys.

But my pressing question was whether I'd have any trouble running two kits -- different sizes but otherwise identical -- at their XMP spec? G.SKILL on this motherboard (Sabertooth Z170 S) gave me no problem for setting them at their 3200 speed spec.

This would only be a question now, because I'd seen some forum discussions elsewhere suggesting that you should either fill the slots with a matched set in a kit, or only choose kits of two sticks. There was nothing authoritative about the exchanges I read.

I think it would be an educated guess that a second kit won't pose a problem. I was just looking for more confirmation about that from someone who'd had an experience with it firsthand. And of course, my interest is driven exclusively by the Z170 chipset and RAM above DDR4-3000 give or take.

Now . . . I've been through the Newegg G.SKILL TridentZ DDR4-3200 inventory at least a few times. My existing kit is -16GTZ with timings 14-14-14-34. What otherwise seems to be an identical kit of TridentZ -8GTZ has spec timings of 16-16-16-36.

TridentZ -16GTZ

TridentZ -8GTZ

TridentZ -32GTZ

So for another $200-plus I could simply get a kit of 2x16 GB with 14-14-14-34. For only $72, I can get a pair of -8GTZ's and the whole enchilada will have to run at 16-16-16-36. It now becomes a question as to whether to spend $244 and put the 2x8 kit up for sale or into the parts locker, or to spend $72 and run at looser timings. The only other possibility is to spend ~$120 for a second set of -16GTZ's, so that hopefully -- the total of four modules will run at 14-14-14-34.

 

[ch33zw1z]

Im actually doing the same thing. have an Asus z170-ar and about to go from 16gb to 32gb using gskill ddr4-3000 dimms

I'm at the latest bios, and the xmp picked up the settings perfect in profile one...I'm not really expecting problems

I'm just repurchasing the same set from order history on newegg

 

[VirtualLarry]

Timings for 16GB DDR4 DIMMs, are different than timings for 8GB DDR4 DIMMs. I would be *really* hesitant to mix them.

 

[BonzaiDuck]

Im actually doing the same thing. have an Asus z170-ar and about to go from 16gb to 32gb using gskill ddr4-3000 dimms

I'm at the latest bios, and the xmp picked up the settings perfect in profile one...I'm not really expecting problems

I'm just repurchasing the same set from order history on newegg

Timings for 16GB DDR4 DIMMs, are different than timings for 8GB DDR4 DIMMs. I would be *really* hesitant to mix them.

I'm newly-inspired today. I set up my three-tiered caching system on this Skylake for the first of two OS's. The acceptable size of an SSD caching volume is about 100 GB. So I have two of those volumes set up -- one for each OS.

I'm now thinking I don't need more RAM to do this, but if I wanted more, I can trim the hiberfil.sys to 15GB and put the pagefile on a cached spinner.

I wish I could get by with the smaller kit, and I think it's a good bet for those that they'd simply set the default for all the modules in all the slots. But the 2x8GB kit is only $50 more and spec'd to 14-14-14-34. I think that would be the way to go.

I can see now that I could get a 1TB M.2 NVMe, clone the OS to it, shrink the system volume to just under 400 GB, install the second OS on another 400GB volume, and divvy the remainder into 100GB chunks.

The way it looks, any other drives in the system might benchmark closer to the M.2's own spec than to either an SATA SSD or HDD. And then, no need to cable an extra SATA caching drive to the motherboard controller.