Explain the PCIE 16x/2.0/3.0/1x etc.

aamatniekss

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Aug 23, 2012
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Im a bit confused about all these PCIe slots. Whats a PCIe 16x, whats 2.0 etc? Which is the one that I need for modern graphics cards? What are the benefits of each? Which slots are the ones that common motherboards should have in order to put in any GPU I want?
 
Solution
pci-e x16 has 16 lanes for traffic. x4 x1 have 4 and 1 respectively and are for things like raid and sound cards wireless adapters and so on.
2.0 is the revision number of the pci-e interface. each 1 brings more bandwidth to the 16 lanes pci-e 3.0 has about x2 the available bandwidth of pci-e 2.0 for instance.
pci-e x16 has 16 lanes for traffic. x4 x1 have 4 and 1 respectively and are for things like raid and sound cards wireless adapters and so on.
2.0 is the revision number of the pci-e interface. each 1 brings more bandwidth to the 16 lanes pci-e 3.0 has about x2 the available bandwidth of pci-e 2.0 for instance.
 
Solution
Ahh, so that x16 or whatever number there is, is the size of the slot?
Is there even any motherboards nowadays, which don't have x16 slot then?
So basically I will insert my GPU in a x16 slot, and the 2.0 and 3.0 are just like a newer and older version, same as for example - USB 2.0 and 3.0?
Then again, can I insert a 3.0 GPU in a 2.0 slot? or 3.0 GPU in a 2.0 slot?
 
PCIe 1.0, 2.0, 3.0 are generations of PCIe. They are mostly focus on increasing of bandwidth (plus some other features). For instance, PCIe 3.0 is twice the bandwidth than PCIe 2.0.

Now, 16x, 8x, 4x, 1x are talking about PCIe speed out of maximum. For example, 8x slot will run at half bandwidth of 16x slot. 16x on the other hand means full speed of PCIe technology on the motherboard installed. Often you can see that motherboards that allow two or more cards install reduce the bandwidth of PCIe slots when more than one card installed. For instance, a motherboard with two PCIe 16x slots may run one PCIe slot at 16x (maximum speed) when one card installed, but then run both slots at 8x each when you install a second card.

Slots are mutually compatible. Cards that are designed for one slot usually work with another slot just fine. For instance, if you have a PCIe 3.0 card (that is designed for PCIe 3.0 slot), it should run in 2.0 slot fine. The only exception I am aware of was 2.1 cards in 1.0 slots may have compatibility issues.

Naturally, if you buy modern technology, you get the current slot which is 3.0 right now.
 


there are some boards that dont carry x16 pci-e but there old or not generally available to customers.
3.0 and 2.0 are backwards compatable rite back to 1.1 revision 1.0 isnt entirely backwards compatible and depends on the chipset running it.

yes you can insert your 3.0 into a 2.0 pci-e for the most part the cards labeled 3.0 are actually 2.0 just re branded.

 


The vast majority of boards have at least one.
 
no mate 2.0 has an issue with 1.0 chipsets that run the slots. these cards were released in 2007. some (most) just wouldnt work in the older 1.0 pci-e chipset standard even though they were reported to be fully compatible. anyways the cards and boards are so old now its not really an issue unless your building a retro rig.

for the most part there is little in the way of comparability issues between 3.0 and 2.0 and certainly no where near as bad as 2.0 and 1.0 compatibility.
if you get a card labled 3.0 theres no good reason why it shouldnt work and even if you do run into an issue there is gpu bios fixes for them. again it only really applies to the first cards released on the 3.0 standard as soon as the problem was noticed most manufacturers reflashed there gpus to make sure they worked.