the cards are the same so speed would not matter (should be the same),
BUT!, u might have some issue with power consomption, throttle cards (because of the hot environment ), cooling the whole system (easier to cool a rig with 4 gpu than 8 gpu.. [my opinion]), incase u intending to use PCI risers (on the 8 rig) u might have some issue with wordlists on fast algori.. , u cant push to much on pci risers they have bottleneck.
overall if u have enough of cooling in ur rig of 8 gpus and u can put ur 8 gpu without risers and u have enough power woltage and ur mobo can support 8 gpu, then u'r good. (i think, some one correct me if im wrong, or forgot somth)
if u ask me, i would go for the setup of 2, i think its safer to go with 2 rigs of 4
(u did not mention that type of hardware u'v got so hard to tell )
BUT!, u might have some issue with power consomption, throttle cards (because of the hot environment ), cooling the whole system (easier to cool a rig with 4 gpu than 8 gpu.. [my opinion]), incase u intending to use PCI risers (on the 8 rig) u might have some issue with wordlists on fast algori.. , u cant push to much on pci risers they have bottleneck.
overall if u have enough of cooling in ur rig of 8 gpus and u can put ur 8 gpu without risers and u have enough power woltage and ur mobo can support 8 gpu, then u'r good. (i think, some one correct me if im wrong, or forgot somth)
if u ask me, i would go for the setup of 2, i think its safer to go with 2 rigs of 4
(u did not mention that type of hardware u'v got so hard to tell )