The rig with 6 different cards is more stable than the rig with 7 same cards?

[Nebell]

I'm curious why is it so?

Rig 1 (6 cards, 3 Gigabyte, 3 Asus)
80% tdp, +180gpu, - 500mem
STABLE for weeks (never crashed)

Rig 2 (7 cards, all Asus Phoenix)
76 TDP,  +150gpu, -500mem
FREEZES every few days

Rig 2 still freezes while rig one has never had any issues.

The only difference is the motherboard, which again is the exact same manufacturer and it's just Z170 vs Z270 (MSI Z170/Z270 Gaming Pro Carbon).
Rig 2 also has a beefier and much better quality PSU (Seasonic Prime Platinum 1200W vs Corsair RMx 850W on Rig 1).

Is there anything I can do?
I'm mining Neoscrypt.

[leonix007]

I'm curious why is it so?

Rig 1 (6 cards, 3 Gigabyte, 3 Asus)
80% tdp, +180gpu, - 500mem
STABLE for weeks (never crashed)

Rig 2 (7 cards, all Asus Phoenix)
76 TDP,  +150gpu, -500mem
FREEZES every few days

Rig 2 still freezes while rig one has never had any issues.

The only difference is the motherboard, which again is the exact same manufacturer and it's just Z170 vs Z270 (MSI Z170/Z370 Gaming Pro Carbon).
Rig 2 also has a beefier and much better quality PSU (Seasonic Prime Platinum 1200W vs Corsair RMx 850W on Rig 1).

Is there anything I can do?
I'm mining Neoscrypt.

 Your GPU cards are also different from rig 1 and 2, that's explains it, usually they have different types of mem clocks sweet spots, just play along with it, until you discover its stability for underclocking or overclocking.

sometimes, a riser is also at fault, ensure those risers are reliable.

[BennyT]

For some reason, I've had trouble with rigs that have Asus only cards. Workaround was use GPU Tweak II instead of Afterburner which is a bit of a pain.

Try taking one of the gigabyte cards and swapping it with one of the Asus cards in the 7 GPU rig. But also the previous poster had good suggestions.

[Nebell]

Well, perhaps I should just downclock it and hope for the best :/
Those few mh/s probably aren't worth the trouble.
I don't feel like removing everything right now, I've had this rig for 7 months.