There's absolutely gas left in the tank in terms of cache. With similar (hell maybe higher) ambient temp, I got 5g ring with 1.7vcore running using a Scythe Fuma 2 for cooling:
I'd like to note that 1.7vcore was absolutely unnecessary. I know I got it to pass at 1.63v, and I think it probably could've passed even at 1.55v.
You are absolutely right about too tight having performance loss. I noticed with one of my old sets, too tight tRFC would tank scores. All my tertiaries are tested for consistent performance gain with this specific kit and board. I know not all motherboards like the same settings, buddy with an OCF and Tachyon said both didn't run well with my timings. I really need to try newer bios, hopefully manual RTL will work, should be a couple hundred ms still available.
Do you think your Raptor was slowing you down? I've always benched on SSDs, as that's just what I've had available to me. Also, 3c3t should have meaningfully lower idle temp, so if 4c4t isn't faster for you, then you'll see other benefits.
If you need different dual rank, I have one more spare set that I need to get rid of. Phone repair bills are a pain, especially in college