I was mostly testing yesterday, I was up to 3.25Mil PPD for the 5x GTX 1660ti box, 1.8-1.9Mil PPD for my main rig with the RX 5700 and GTX 1660ti Gaming X, but that dropped down to 1.1-1.2Mil PPD with PrimeGrid using all of the CPU threads. Also one of my secondary rigs, was doing around 600-700K PPD, when according to that PPD database site, the RX 5600XT should be doing 800-900K PPD, and the GTX 1650 D5 should be doing like 450-500K PPD, for a total of around 1.3Mil PPD.m That box was also running PrimeGrid on all 12 threads.
So what I think that I'm going to do, for the race is, I'm going to use ONLY my NVidia cards for F@H, and leave the AMD cards (with superior MH/sec on ETH) mining. (I need the money.)
That will give me, 5x GTX 1660ti on mining rig for 3.25Mil PPD, and a GTX 1660ti Gaming X on my main box for 1.0-1.1Mil PPD, and then the two secondary boxes have GTX 1650 D5 cards, that supposedly will do 400K+ PPD, so that's still my estimated 5Mil PPD, more or less.
That will give me still, 37-40MH/sec on two RX 5600XT, 49MH/sec on my RX 5700, 49MH/sec each on my two RX 5700XT (although one likes to drop to 33MH/sec for some reason, unsure if my card is defective, or if I need a more stout PSU on that box.)
Another wildcard is, I was thinking, instead of trying to acquire an i7-6700 CPU for the mining rig, to get a "fifth core" equivalent to scale up the F@H support to maybe 4Mil PPD, instead, I would replace the whole H110 PRO BTC+ (13x GPU support), with an Asus ROG STRIX B450-F Gaming ATX board that I have BNIB, and slap in a Ryzen 1600 6C/12T CPU, and move the GTX 1660ti Gaming X dual-slot card into my mining rig, giving me 6x GTX 1660ti, and then getting a couple of M.2 NVMe to USB-connector PCI-E riser do-dads, so that I could have 8 GPUs connected, and then use my SeaSonic 1200W Platinum PSU, which has 10x 6+2-pin connectors, for the 6x GTX 1660ti cards (they take a single 8-pin), and then move the two RX 5700XT Asus Dual cards into the mining box as well, to fill up the 8-card space-limit, and use 4x PCI-E power cables for those (8-pin plus 6-pin).
Then use SATA-to-6-pin adapters, and use the SATA leads off of the 1200W Platinum PSU, to power the riser card slots. (I would need to buy another 6-pack of risers, to get a few more.)
Then I would have potentially the CPU "grunt" to run F@H across all 6 cards, or at least, one the 6 GTX 1660ti cards, and do mining on the 2x RX 5700XT, when I'm not mining on all 8 cards. It would also reduce the space taken up, as I currently have the 2x RX 5700XT cards in yet another rig, that's sitting on top of my mining server, and it looks a little bit messy, should I have an apt. inspection in a few months.
The problem is, to get to this ideal situation, will take some "real work", tearing down the mining rig (4U or 6U mining chassis, it's kind of heavy, esp. populated), and re-building it with a new PSU and a new mobo, re-installing Windows, getting the mining risers to work with the Asus B450-F R.S. Gaming board, which is not especially marketed as a mining box. (But I know that it is used as such.)