Dimm.2 causing ram to overheat

I’m overclocking my ram. Have pretty tight timings at 3,800 mhz 15-15-15-23. I could probably get a little more performance out. Definitely, hit the lowest possible value for tRAS if I could cool one bank of memory a bit more.

Currently, one bank runs about 4c to 7c more. I already have 2 NF-F12s pointing at each bank of ram. The highest stick hits 50.5c after an hour of stress testing. If I could keep that under 50c I think I can get the fastest possible ram settings stable.

I could upgrade the Phanteks 140mm default case fans to four T30-120, which I believe should improve case airflow slightly. Pretty sure, it’s the dimm.2 riser card that’s causing the extra heat on a bank of memory. I am going to separate my ram fans to a separate channel than the case fans soon.

Are there any other means of dropping temperatures? Maybe, putting a piece of cardboard between ram and dimm.2?