Pci Express 2.0 vs 3.0 backwards compatible

[Hotkiker]

hello everyone

back again with more questions. Lets start by telling my situation. A month ago i decided to build a new gaming pc. Picked up most of the parts on sale.So far what i have bought is

cpu- i7 2600k
gpu- Evga Gtx 670 FTW
psu- 950w
motherboard- Asus Maximus V Formula z77
Ram-16gb 1600 G.Skills

I thinks that's about it. Now as soon as everyone read this there going to tell me that i should have bought the i7 3770k. I know and i would have if it did not run as hot as it does. Alright forget that. What i really wanna know is how does this backwards compatibility work. I don't understand.

If i am running my gpu on the x16 slot will it run in x8. All of this is very confusing and i need all the help i can get.


oh and will there be a bottleneck if i sli in the future. Please do ask any question if it will help resolve my question.


TY

 

[de5_Roy]

if you're using single card, and have it seated in the top pcie x16 slot, it'll run on x16 speed.
if you're running dual cards in sli, have the second card in the second pcie x16 slot (which likely runs @x8), then both cards will run at x8+x8 mode. if you check your mobo's manual you'll see how the pcie slots are configured to run. usually it's 1st slot @x16/x8(for dual cards) and second slot @x8 mode.
since core i7 2600k's integrated pcie controller is gen 2.0, the card(s) on the pcie slots(s) will run at gen 2.0 speed. pcie 3.0 and 2.0 are compatible and afaik gaming hasn't shown any substantial improvement with pcie 3.0 yet.
from asus
http://www.asus.com/Motherboards/Intel_Socket_1155/Maximus_V_FormulaThunderFX/
Expansion Slots 3 x PCIe 3.0/2.0 x16 (x16 or dual x8 or x8/x4/x4) *2
1 x PCIe 2.0 x4
3 x PCIe 2.0 x1
1 x mini-PCIe 2.0 x1 *3

 

[Hotkiker]

thank u sooo much. U have helped me a lot was kind of worried but now i think i can enjoy building my gaming pc. TY

oh and 1 last question

whats with the (*2) at the end of (x16 or dual x8 or x8/x4/x4) *2 <--what that for?

 

[renz496]

If i am running my gpu on the x16 slot will it run in x8

that only happen if you're running dual gpu configuration or the slot itself were rated at such speed from the get go. for gaming performance there are no difference between PCI-E 2.0 and 3.0. at least for now. i think this article should give you more information about your second question:

http://www.hardocp.com/article/2012/07/18/pci_express_20_vs_30_gpu_gaming_performance_review

 

[de5_Roy]

thank u sooo much. U have helped me a lot was kind of worried but now i think i can enjoy building my gaming pc. TY

oh and 1 last question

whats with the (*2) at the end of (x16 or dual x8 or x8/x4/x4) *2 <--what that for?

that's the reference to the footnote in the asus webpage.
refered to this -
*2-1: PCIe 3.0 speed is supported by Intel® 3rd generation Ivy Bridge Core™ Processors.
*2-2: x8/x4/x4 mode is supported by Intel® 3rd generation Ivy Bridge Core™ Processors.

 

[Hotkiker]

Best answer selected by Hotkiker.

 

[Hotkiker]

ok thanks De5_roy and renz496