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GT1030 are fairly low power devices and there are now two editions. GT1030 with GDDR5 and GT1030 with DDR4. The ones with DDR4 are to be avoided, so be sure to check the packaging (if available)
Zotac started out as a bargain brand, but they've expanded greatly into the high end market. This would be part of their bargain offerings. Palit has typically produced hardware for OEMs from my understanding. So lowest cost is the target for bulk orders. Gigabyte has been around forever and would normally suggest them. (Though I haven't had a Gigabyte GPU in many years)
I would say lowest cost is now bad advice for GT1030, lowest cost GDDR5 model. Then you can look at clock speeds and cooling.
Though if you want more performance, just go for a GTX1050 or RX560 (And there are now two versions of the RX560 with different compute power)