No, you have only 1 PCI Express slot.
So, let me get this correct: If i buy a motherboard with a PCI express slot, regardless of version, i can mine with it, correct? And if i buy one that has 2, then i can have 2 gpus.
Yes, you need 1 PCI-E slot for each GPU, you can mine with a x1 PCI-E slot as quickly as a x16 PCI-E slot
It does not matter if the motherboard is PCI-E v2 and the card is PCI-E v3 as the card will downgrade its connection.
PCI is not the same as PCI-E, it is a different type connection.
Thanks!
One more question: the card needs at least a power supply of 500W. If i install 2, do I need a power supply of 1000W?
That seems very high, according to the Sapphire site each of its R9 270X required 2 x 75W PCI-E power connectors, so 150 Watts per card, add 250 watts for a mobo, hard disk, dvd fans, etc would give you 400 - so a 500W power supply would give an efficient supply.
For 2 x R9 270X cards you would need a 650watt PSU or better.
OK i just mistyped, I want to buy a Gigabyte one.