Restoring old r270 mining rig

[rarecoil]

• I'm tempted to install fresh linux on new hdd with ROCm drivers (for sake of some improvement). Will they even work with R9 (I mean without crashing constantly etc)? Is it worth spending time to toy with them with those ancient GPUs or should I better roll with what I've got? 
  

ROCm likes modern cards. The oldest supported card is Hawaii (GFX7, R9 390X). I have not had successes using ROCm with GCN 1.0 cards, and OpenCL pulled from amdgpu-pro does not appear to work. The only working OpenCL for GCN 1.0 on modern kernels appears to be the ancient mesa OpenCL which is slow and IIRC never was supported by hashcat/oclHashcat.

You would probably get better speed and definitely better perf-per-watt from selling all the old components and buying a single mid-level Pascal card used on eBay, or at least upgrading to a Polaris. That said, working on old tech is fun

• I'm planning to invest in some HDDs to expand wordlist storage. I'm on a budget so I'd go for 4 consumer magnetic drives instead of SSD. Now I'm wondering whether it is worth to make zfs or other raid0 setup to speed up the I/O. My bet is that hashcat will hardly benefit from faster io (only when loading wordlist into gpu ram, right?) and I will only get some slight improvement when processing wordlists. Or am I wrong?
  

A 2TB Samsung 860 Evo is less than $200 from eBay. A single 10TB HGST can be had for around the same price refurbished on eBay. I have a lot of large wordlists that I store compressed and just expand when I need them into memory or SSD space. My entire wordlist collection is less than 500GB compressed. I would recommend simply using a small SSD and worrying about expanding this if/when you need the space.

• The rig is based on hacky tape-based risers for GPUs. They work fine - any benefit from the ones based on usb3? apart from looking nicer and costing more perhaps not having fire in house?
  

I am using ribbon cable risers on my rig right now and have had no issues with them. Most power draw is through the PCIe connectors.