I think you might be able to squeeze a little bit more speed using -n 0x4000000000000 -k 8192. If you saved your 1TB bloom filter using -S, you can re-use it with the different -n and -k values. You have another 0.5 TB ram available, have you tried -n 0x4000000000000 -k 12000 so you can max out your RAM? Even then, you'll run out of money or die before 135 is found.
I will try with -n 0x4000000000000 -k 8192, but for every different command I need to wait a couple of hours for the bloom filter to fill the RAM.
I tried also with all the 1.5T RAM but the speed is considerably slower because on a dual socket system, each CPU typically has its own memory controller and dedicated memory channels. This architecture is known as NUMA. Latency increases and bandwidth decreases when a CPU accesses the memory attached to the other CPU.
So I'm running 2 separate keyhunt apps with these commands : numactl --cpunodebind=0 --membind=0 ./keyhunt0 -m bsgs -f 135.txt etc etc (1T RAM)
and numactl --cpunodebind=1 --membind=1 ./keyhunt1 -m bsgs -f 135 etc... (512GB RAM).
You are right, 135 is very hard but better to try my luck on random than going sequentially specially on these high ranges puzzles.
Just ordered from Ebay China an EPYC 9965 with 192 cores / 384 threads and 1T of DDR5 at 6400Mts/s , the speed will be about 5-6x higher on this new setup. More than 15k euros put into these puzzles without even knowing I will get 1 penny back.