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will PCI 2.0 bottleneck 700 series ?

B

brandon888

Senior member
hey guys ... im on my I7 3930k ... it supports only pci 2.0 as i know ..... 600 series are okay with pci 2.0 16X slots but how about 700 series ? and rumored titan card ? will be there pci 2.0 bottleneck ? or i will be fine even with maxwell 800 series ....

im asking because here

http://tpucdn.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/images/perfrel.gif

we see that even old pci 1.0 16X can use 95% power of gtx 680 :O
 
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lehtv said:
No, it won't matter whether you're using 2.0 or 3.0. It matters only when using multiple cards because it limits the bandwidth available per card and imposes a higher load on the PCIe controller.

http://www.techpowerup.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/23.html
Click to expand...

thank you bro 🙂 i use single card always so no problem with that 🙂 then i will be fine even with maxwell i guess 🙂

here i see i7 3930k with pci 3.0 .... look at GPU-z 😛

http://img.hwbot.org/u23828/image_id_818643.jpeg


thank you all and sorry ... i don't trying to troll here ...
 
I think the card running in 4x 2.0 vs 4x 3.0 would be significant, but I doubt there is much difference when using 16x...

OT but I will ask anyway,

is there any way, registry tweak or something, to force a PCIE 2.1 card + PCIE 2.0 MB to work in PCIE 1.1 mode?

it was hard to find anything using google.
 
Windows registry has no options for PCIe mode, it's a hardware thing. I have no idea if a motherboard with a 2.0 controller can even be set to function in 1.1 mode, but if it can, you'll find that option in the BIOS
 
lehtv said:
Windows registry has no options for PCIe mode, it's a hardware thing. I have no idea if a motherboard with a 2.0 controller can even be set to function in 1.1 mode, but if it can, you'll find that option in the BIOS
Click to expand...

the motherboard definitely can (but there is no option on the bios), or it wouldn't support old VGAs (like a 8800GTX), I thought there was maybe some driver side thing, like with the PCIE 3.0 + SB-E/GTX 6xx
 
SPBHM said:
the motherboard definitely can (but there is no option on the bios), or it wouldn't support old VGAs (like a 8800GTX)
Click to expand...

Yes, I know the PCIe 2.0 controller is backwards compatible with 1.1 devices. But with a 1.1 device I believe it will still be functioning in 2.0 mode, just limited in bandwidth by the device. Someone correct me here if I'm wrong.

However, Z77 boards (at least mine) can switch between PCIe 3.0 and 2.0 modes in the BIOS so they can actually force a 3.0 device to 2.0 bandwidth.
I thought there was maybe some driver side thing, like with the PCIE 3.0 + SB-E/GTX 6xx
Click to expand...

Sandy Bridge-E has supported PCIe 3.0 from the beginning, it's not a driver thing.
 
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lehtv said:
Sandy Bridge-E has supported PCIe 3.0 from the beginning, it's not a driver thing.
Click to expand...

yes but, NV drivers would make the card work in 2.0, unless you modify something,

I think with some cards, Windows power saving feature can also force a slower PCIE mode (1.x speed), so there must be something possible,

both the MB and VGA can work with PCIE 1.1, so my intention was to simply force this mode (when the default is 2.0 for the combination)
 
lehtv said:
Sandy Bridge-E has supported PCIe 3.0 from the beginning, it's not a driver thing.
Click to expand...

Some motherboards do and some don't and some of the earlier stepping CPUs also had problems. When SB-E was released PCI-E 3.0 was meant to be supported but in practice there were no GPUs to test with, and when it was released PCI-E 3.0 was not on the support list. The motherboards did support it but once the cards actually came out some didn't meet the specification precisely and it was a hardware problem.

If you buy a modern motherboard and CPU then it should support PCI-E 3.0, if you bought when it came out it might support it, and it might appear to support it but actually not do so perfectly causing crashes and freezes.

SPBHM said:
yes but, NV drivers would make the card work in 2.0, unless you modify something,
Click to expand...

Nvidia's cards don't like the timing problems of the early SB-E's and since the extra bandwidth makes no practical performance difference they disable it on all SB-E's. Its easy enough to modify the registry and bring it back, but you will want to be quite sure that the machine does indeed support it, not just that it says it does in the bios.

My 7970's worked at 3.0 but my 2x 680's do not, they crash every few hours. Seems to me my Asus X79 pro and/or 3930K (first stepping) don't support it fully even though the 7970s doesn't have a problem.
 
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