What is the difference between 4870 and a 4870x2?

Is a 4870x2 basically two 4870's? Why not get two 4870's instead of getting a 4870x2?Also, when using crossfire can u have 4 4870's and the most you can crossfire with a 4870x2 is 2 of them?It is just a little confusing.Is a gtx 295 in a way a gtx 295x2? Just they decided to come out with the x2 and not just a single gtx 295?What is the difference between 4870 and a 4870x2?
There are more people with one PCI express slot than two.What is the difference between 4870 and a 4870x2?
OK so the 4870x2 takes up 1 slot where as having actually 2 seperate ones takes 2. Got itWhat is the difference between a PCIe x16, PCIe x16/8 and a PCIe x8?
bandwidth is the difference. 16x (4gb/s) has faster bandwdith than 8x(2gb/s) so if you pair two cards and your board has two pcix slots make sure it can support 16 dual if not it will mostly likely do 8x/8x which isnt very good. This is why 4870x2 is a better choice as it will run at 16x since it is using only one slot not all boards support 16x on both picx slots so read up on them to make sure. Of course in the past this didnt matter too much as the cards or the games at the time couldnt take full advantage of the 16x or even 8x for that matter but nowadays it makes a difference. 16x/16x will perform better than 8x/8x but of course one 8x/8x will perform better than one card 16x unless its dual gpu. Hope this gives you a basic understanding.
what about 16x/8x?what does this mean.... ''3 x PCI Express 2.0 x16 slots (operates at 16x/16x/4x)''or this....''3 x PCIe 2.0 x16 (@ x16 or x eight)
3 x PCIe 2.0 x16 (@ x eight)
1 x PCIe 2.0 x16 (@ x 16)''
They actually have different physical sizes. The higher the # the larger the slot. [img]http://static.howstuffworks.com/gif/pci-express-slots.gif[/img]