The 42 recommendation for tRC is anomalous as it doesn't follow the rule. The G.Skill recommended 56 is for 3200 and may well work at 3333, but may require a little voltage bump. Pairing a little off tRP (1 or 2) and a little more off tRTP (2 to 4 or more) can help. Ideally you want tRP + tRTP = tCL + 4, and the closer you can get to that the better.
When you were at tRC 60 and tRFC 520 did you have stability?..
Edit: Edit: Sometimes a BIOS reset makes all the difference, as it forces the board to re-learn the RAM. Definitely don't go below the G.Skill spec'd tRC until everything is good and you want to get deeper in the rabbit hole. Many/(most) RAM timings are interdependent.
Decided to give this another go around, after reading a bit more and overclocking my CPU. Went back to 3200 as per @Bond007, and reading more about CL vs frequency it just didnt seem to be worth the trade off. I just tried to tighten the timings by going low and slow;
Default 3200mhz 16-18-18-18-38-56
Tightend 3200mhz 14-17-17-17-30-56 (I cannot get that tRC any lower than 56)
It did improve my memtest bench from 137 to 131. I'll take a free 5%!
I may try to loosen the timings and get up to 3400 so that I can have a higher Fclock & Memclock @1700, and see the different results I get in synthetics. From what I'm reading online the answer is 'not worth it'.
edit: further tweaking based on rereading @Valkyrie posts, I raised tRP to 18, tRAS to 36, and followed the formula for tRC of 54, multiplier of 9 for tRFC (486). Bench Score was within margins of error. I may leave it like this anyways, assuming that these formulas are 'the correct' way of doing this. Not sure who says they're correct tho lol
Don't worry about tRC. Just leave it at 56 and try sneaking down tRFC. I may be wrong about that integer multiple bit, it's been a while. I'm planning on firing up an OC'ing system soon and I'll give a definitive answer on that...(meantime you could try it yourself...carefully.) As mentioned tRFC is when the bank is unavailable for any access. The refresh needs to complete successfully to prevent corruption.
Definitely don't unnecessarily increase tRP or tRAS. There's a desirable condition called "hidden (or partially hidden) precharge" that makes burst transfers much more efficient. That is why we try to achieve as close to tRP+tRTP = tCL+4 as we can...(for DDR3 and DDR4.) If you don't do anything else this would be a good task to work on. Note that tRTP can normally be cranked down more than tRP.
Edited for typos and syntax. I didn't get the better half to check it though so......
I consider an OC'ing system to be one that you don't mind reinstalling the OS on a moments notice. The tRP an tRTP tweaks are usually somewhat forgiving, but no guarantees. Still, it's worth trying to achieve the hidden precharge carefully.
Hardware Canucks is focused in-depth reviews of the the latest graphics cards, CPUs, storage, smartphones, notebooks and gaming peripherals. Join us as we unbox, review and benchmark the best computer hardware on the market.