I'm seriously considering taking advantage of the anniversary sale on PBE 3 Pro. I have a few questions before pulling the purchase trigger.
Will PBE's "Universal" optimized memory timings significantly boost performance mining ProgPoW algo?
If/when Ethereum makes the transition from Ethash, might specific timings be developed for ProgPoW in future versions of PBE?
Given how core-intensive ProgPoW seems to be, might undervolting deleteriously effect hashrate too much to make it worthwhile?
I don't know the exact changes, from what I know it should be keccak so it will be boosting hashrate as long as it use memory. After the fork or at least final changes we can look at it. When Monero fork againts ASICs the timings remained the same for example. Even if there won't be specific timing for this algo, it will give better hashrate if the algo is memory intensive. It's like you can use XMR timings to mine ETH, the hashrate won't be as good as it might be, but still far better than stock.
Not sure what you mean with the undervolting part, but as long as I know they want it to have lower total power.
Also it will take at least half a year probably even more to implement such a changes to ETH so it is very hard to give you my final opinion on this.
I can only promise you, that if you once buy PBE whatever version, you will receive every update for free then, but if there will be new ETH algo, can't really tell now. BTW there are always some discount coupons higher or lower. Currently the best you can have is 50% off on the Lucky Wheel.