[SOLVED] Performance with 3 sticks of ram

[nfs_boy]

So I've heard you can use 3 sticks of ram on your motherboard, but I've also heard it could decrease performance because you have to use one stick in single channel mode. My question is, if ram usage stays under 8gb (assuming there are 2x4gb sticks running in dual channel and one 4gb stick running in single), will performance not be affected? Will the computer use the two 4gb sticks in dual channel mode until they are full and then resort to the single 4gb stick for extra space?

 

[Darkbreeze]

Most systems these days will use a "Flex" mode, where the memory that can be used in dual channel, is, and the remaining memory is used in single channel. What is your platform? Motherboard and CPU models?

 

[nfs_boy]

I use an i3-8350k on a Gigabyte Z370P D3

 

[geofelt]

No idea if windows is smart enough to recognize that some ram locations are faster than others. I have my doubts how that could work.
12gb of ram compared to 8gb can only be a plus.
If you have such a configuration that works, you can test it out yourself with YOUR apps. Try 8gb and 12gb and see how you do.
Intel is not much impacted by ram speeds anyway

 

[Calvin7]

DDR4 memory is not sold in 3 module kits. Adding extra memory has no guarantee to be compatible with existing memory. You can do your own testing with no guarantees as to how it will work, if you can get it to boot up.

 

[Darkbreeze]

Yeah, we realize that Calvin, in fact I'm probably the biggest advocate of making recommendations against doing that, but unless they are running sticks that are beyond JEDEC standards and in an OC/XMP configuration, the chances of them not playing nice are pretty minimal unless they are wildly different configurations. Certainly, it happens, and just going with a 2 x8GB kit would be the better option, but if that isn't possible then there is no reason to not at least try what they have in mind unless it becomes a major hassle to lose 4GB of memory if you end up having to only run the two stick kit.

What are the model numbers of the memory you have now and the memory you are planning to get? On that Z370 board, it is VERY likely that Flex mode will be supported.

You can verify EASILY once they are installed by running Typhoon burner or CPU-Z, and looking on the memory tab for dual channel verification. Not sure if it will list flex or not, I believe it will. But if any sticks are running in dual channel it should list it.

 

[nfs_boy]

Yeah, if I do end up doing this I'm planning on playing it safe and getting the exact same model of memory I already have (Ballistix Sport LT 4GB Single DDR4 2666 MT/s, BLS4G4D26BFSB). This should be the exact same as my current RAM, but I'll check the model number later just to make sure.

 

[Darkbreeze]

Getting the same "model" is not the same as getting the "same" sticks, at least not always, and USUALLY not even "often" especially if it's been a while since you purchased the original memory.

Here's why:

https://forums.tomshardware.com/threads/amd-ram-compatibility.3210050/post-19785792

And this:

https://forums.tomshardware.com/thr...gb-xmp-profile-problems.3462507/post-20935690

And since your sticks ARE within the JEDEC spec, they probably WILL play nice together even if there are some differences (Which there can STILL be, even using the same model, if they did not ALL come together), but there is ALWAYS a chance they might not when any memory module in the group did not come together with the others.

If it were ME, I'd recommend that you get a 2 x8GB set, and sell your current 4GB stick or keep it for use with another build or as a tool for troubleshooting memory problems in the future. The thirty dollar difference, if you can swing it, is probably well worth it. Plus, if you sell the current stick for twenty bucks, then you're only paying ten bucks for an extra 8GB.

PCPartPicker Part List

Memory: Crucial - Ballistix Sport LT 8 GB (2 x 4 GB) DDR4-2666 Memory ($47.95 @ B&H)
Total: $47.95
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-05-05 02:56 EDT-0400


PCPartPicker Part List

Memory: Crucial - Ballistix Sport LT 16 GB (2 x 8 GB) DDR4-2666 Memory ($82.01 @ Amazon)
Total: $82.01
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-05-05 02:57 EDT-0400

 

[geofelt]

Buy a 2 x 8gb ram kit with the same specs as your current ram.
You will be guaranteed a working dual channel 16gb of ram.

Then, try installing your two existing 4gb sticks.
If it works, good, you now have 24gb.
If not, sell the old 8gb or keep it as a spare.