Question Adding RAM

[BoomerD]

I have an ASRock Z390 Phantom Gaming 4 board that came with 2x8gb APacer Ram. I have the opportunity to get 2x16gb of Corsair Vengance that's compatible with the board and processor.
First question...since the RAM doesn't match my existing sticks...remove the 2x8 APacer and just use the 2x16 Corsair?
If so, IIRC, on some boards, the different slots (A1-B1 or A2-B2) might work better with dual channel RAM than the other way.

Thanks.

 

[igor_kavinski]

What are the speeds of both RAM kits? Even if you install all four of them, it should work fine, just it would be at the lowest stable speed the motherboard can get them to work at. Put Corsair in A1-B1 so both of them can do dual channel. Run Geekbench 5 to see what score you get. Then add the Apacer modules to A2-B2 and run GB5 again and note if there is any serious regression in performance. If not, you can keep using them together.

 

[BoomerD]

What are the speeds of both RAM kits? Even if you install all four of them, it should work fine, just it would be at the lowest stable speed the motherboard can get them to work at. Put Corsair in A1-B1 so both of them can do dual channel. Run Geekbench 5 to see what score you get. Then add the Apacer modules to A2-B2 and run GB5 again and note if there is any serious regression in performance. If not, you can keep using them together.

The Corsair ram is cmk32gx4m2d3600c18,

https://www.corsair.com/us/en/Categories/Products/Memory/VENGEANCE-LPX/p/CMK32GX4M2D3600C18

The APacer ram is AU08GGB26CQYBGH
AU08GGB26CQYBGH | Apacer 8GB DDR4 Memory AU08GGB26CQYBGH (ascendtech.us)

 

[igor_kavinski]

The Apacer RAM is almost 1 GHz slower so it will force the Corsair RAM to slow down with it. If you don't need the extra 16GB, just put the Corsair in A1 and B1.

 

[BoomerD]

The Apacer RAM is almost 1 GHz slower so it will force the Corsair RAM to slow down with it. If you don't need the extra 16GB, just put the Corsair in A1 and B1.

just looked it up. Motherboard manual says A2-B2 for a single pair.
Thanks for the input. I'll remove the Apacer and just run the Corsair. (that's what I thought about the speed difference...no sense in buying faster RAM then forcing it to run slowly.)

 

[igor_kavinski]

(that's what I thought about the speed difference...no sense in buying faster RAM then forcing it to run slowly.)

Only reason to run it slower would be for tighter timings (CL16 or lower). That will help with applications/games that need data quickly from RAM but applications that prefer getting huge chunks of data from RAM will suffer. The latter ones would be multithreaded apps like Handbrake or Cinebench or Blender. Some game engines prefer faster RAM timings while few others make good use of extra CPU cores so they will want more bandwidth. I bought a Kingston RAM kit for a friend that worked at DDR4-3200 at CL16 and DDR4-3000 at CL15. We decided that 200 MHz wasn't a big deal so went for the lower latency. Interestingly, we also disabled hyperthreading on it because it was giving higher single thread score with Geekbench so the 3000 MT/s was distributed between 6 cores rather than 3200 MT/s between 12 threads.