That's a difficult question. The GTX cards have a base clock and a boost clock, which is automatically generated by the base clock value. Each manufacturer chooses a certain base clock for his card, so different brands of the same GPU type have different clock rates. In addition a card can be manually overclocked.
But the maximum clock can only be reached if it doesn't hurt the power limit (which is adjustable) or the temperature target (also adjustable). And each GPU has its individual maximum clock rate at which its running fine. At some its higher, at some lower.
The higher the power limit, the more heat the cards produces. The more heat it produces the more energy is needed. So there is a limit somewhere. With two or more cards in a rig the cards start heating up each other. They don't get as much air as when running alone aka running hotter. Their performance now also depends on how much air you're shifting through the chassis.
If the GPU reaches its limit it will crash, a scenario you want to avoid at all.
Maybe you can already see the term "is hurting performance" makes no sense. You can put the power and temperature target to 125% and run a standard reference card at stock clock. No big deal, no performance hurting. Until you find out that other people with the same card run 250MHz higher. You start overclocking your card and they might hit their power or temperature limit. The card starts throttleing. Do we now hurt performance, although we're running way higher than stock clock?
Now you might get what epixoip meant when he said: "But this depends on you knowing how to tune everything properly."
But the maximum clock can only be reached if it doesn't hurt the power limit (which is adjustable) or the temperature target (also adjustable). And each GPU has its individual maximum clock rate at which its running fine. At some its higher, at some lower.
The higher the power limit, the more heat the cards produces. The more heat it produces the more energy is needed. So there is a limit somewhere. With two or more cards in a rig the cards start heating up each other. They don't get as much air as when running alone aka running hotter. Their performance now also depends on how much air you're shifting through the chassis.
If the GPU reaches its limit it will crash, a scenario you want to avoid at all.
Maybe you can already see the term "is hurting performance" makes no sense. You can put the power and temperature target to 125% and run a standard reference card at stock clock. No big deal, no performance hurting. Until you find out that other people with the same card run 250MHz higher. You start overclocking your card and they might hit their power or temperature limit. The card starts throttleing. Do we now hurt performance, although we're running way higher than stock clock?
Now you might get what epixoip meant when he said: "But this depends on you knowing how to tune everything properly."