This. Run ONE instance of the stratum proxy. It will identify individual clients and treat them as such. Even if you have different hash rates, set them all at the same difficulty.

That doesn't fit with my experience, and I switched back last night just to be sure before I said anything.

I'm running 2 cubes, and if I point them both at the same instance of the proxy, both run consistently in the 36 range, with my pool reporting a combined of almost 72.  If I point them at two different instances of the proxy, on the same PC, one runs consistently at about 38.8 and the other at about 38.2, with my pool reporting just over 76.  It's a small difference, and I can't say I've been particularly scientific about my testing, but nevertheless it seems to be easily replicated.

YMMV, but I'm a fan of 2 copies of the proxy.

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