No, you should not let your friend mix his RAM.
No, you should not let your friend mix his RAM.
Your friend's setup is a bit unique. The 8GB GSKILL sticks have different timing compared to the 4GB DDR3 sticks, but both are DDR3 and 12800. You can mix them in the same system without issues, as long as they're compatible with the motherboard and BIOS. Enabling XMP won't cause a problem here, as long as the RAM sticks support it. Just make sure the system supports the maximum speed of all installed RAM.
should allow easy installation with 24GB RAM in Cursed Tri Rank. If the Samsung is dual-sided, it might offer quad rank timings; otherwise, performance will likely match the lower standard, which should still run smoothly at around 1600.
It would help to place them in the slots from left to right as 8G, 8G, 4G, 4G. This should work with dual-channel and maintain the same RAM amount per channel to avoid issues. Then I can verify it using CPU-Z.
they leave 8gb in single channel, so try 4g 8g 4g 8g if you can. gskill seems likely to be based in Samsung too, since many of those cheap JEDEC heatspreaders are from that region. Even if it's a different revision, the issue is usually the same—walls at around 2400mhz and revisions often work together. Mixing manufacturers can be a bit tricky, but the core specs usually match.