Maximum Memory bandwidth of PCI 2.0 ???

[brandon888]

sorry for noob question but i mean for exlample that GTX 680 has 192 Gt/s Memory bandwidth ... radeon 7970 has like 264 Gt/s so what is the maximum Memory bandwidth of PCi 2.0 ? when it will be limited ? for example if nvidia will make GTX 780 with more then 300 GT/s Memory bandwidth ... ?


i just want to know when will PCI 2.0 bottleneck Memory bandwidth of GPU ? when it will have 300 GT/s ? 400 Gt/s ? or even more ?

 

[ShintaiDK]

PCIe is a bus, not memory. And it depends on lanes.

PCie 2.0 x16 is 8GB/sec.

The memory speed you refer to is only located on the graphcs cards.

 

[brandon888]

PCIe is a bus, not memory. And it depends on lanes.

PCie 2.0 x16 is 8GB/sec.

The memory speed you refer to is only located on the graphcs cards.

so you mean taht Memory bandwidth of GPU has nothing to do with PCI bandwidth ? Then what a specification of GPU is sensitive to PCI bandwidth ? I hope you understand my question

I mean ... can i understand will or will not bottleneck PCI 2.0 My GPU if i jsut look at GPU specifications ... and if yes then how ? or there is a only way to wait for reviews to see difference ?

 

[ShintaiDK]

PCIe 2.0 wont bottleneck you at all.

 

[brandon888]

PCIe 2.0 wont bottleneck you at all.

so even with 700 and 800 series im safe ? ok it;s hard to answer i know but okay i just wanted to know how detect bottleneck

and one more thing .... i saw benchmarks with 690 quad sli and they was with I7 3930K or I7 3960X .. so i can afford GPU like power of 2 690 and it will not be bottlenecked by pci 2.0 ? maybe jsut bottlenecked by cpu power yes ?

 

[aaksheytalwar]

Single 680
Next to no bottleneck

Dual 680s
Small bottleneck

Tri 680
Significant bottleneck without 3930k

Single 780
Can't say

Single 880
Bottleneck huge

 

[brandon888]

Single 680
Next to no bottleneck

Dual 680s
Small bottleneck

Tri 680
Significant bottleneck without 3930k

Single 780
Can't say

Single 880
Bottleneck huge

even if 880 will be less powerful then 2 680 .... i will get bottleneck anyway ?


Tri 680
Significant bottleneck without 3930k

what that means ? CPU power will bottleneck in Tri sli or just pci 2.0 slot ?

 

[aaksheytalwar]

880 will be more powerful than 680 sli. Just like 680 is more powerful than 480 sli or at least comparable. And it is the arch etc that matters,

 

[brandon888]

880 will be more powerful than 680 sli. Just like 680 is more powerful than 480 sli or at least comparable. And it is the arch etc that matters,

i have I7 3930K with Asus P9X79 .... my mobo supports pci 3.0 but cpu not ..it's a marketing trick as i understand cause there is no single cpu on 2011 socket that supports Pci 3.0 ....



so if i put 880 for example and 880 will be like 20-30% faster then 680 in sli .... then i will be CPU bottlenecked or PCI 2.0 bottlenecked ? or With I7 3930K i will be fine with 880 ?


PCI express bandwidth has nothing to do with GPU memory bandwidth ya ?

 

[aaksheytalwar]

By the time 880 releases a 3930k will be junk. In fact by the time 780 releases haswell would have bashed all current CPUs.

 

[brandon888]

By the time 880 releases a 3930k will be junk. In fact by the time 780 releases haswell would have bashed all current CPUs.

So .... You mean that i anyway will be CPU power bottlenecked before PCI 2.0 bottkenecked ya ? IDK but as i know I7 3930K can hande 3 GTX 680 in games .... (i don't give a fuck about 3d mark and ect ... )

and im about 1080P resolution OFC

BTW .... I7 870 is old cpu but overclocked can handle 680

 

[zephyrprime]

Bus bandwidth doesn't bottleneck anyone these days except for people with crummy video cards. With crummy video cards, you have to shuffle textures back and forth a lot thereby using a lot of bandwidth. But how many people even suffer from this situation? Not many. Even low end cards often have 2GB of memory. And the lowest end graphics solutions are embedded onto the cpu so bus bandwidth is not an issue (although memory bandwidth is). Without having to shuffle lots of textures back and forth, the next biggest user of bandwidth is vertex data but that isn't nearly as sizable and is easily handled even by pcie 1.0.

 

[brandon888]

Bus bandwidth doesn't bottleneck anyone these days except for people with crummy video cards. With crummy video cards, you have to shuffle textures back and forth a lot thereby using a lot of bandwidth. But how many people even suffer from this situation? Not many. Even low end cards often have 2GB of memory. And the lowest end graphics solutions are embedded onto the cpu so bus bandwidth is not an issue (although memory bandwidth is). Without having to shuffle lots of textures back and forth, the next biggest user of bandwidth is vertex data but that isn't nearly as sizable and is easily handled even by pcie 1.0.

so as i understand i will not be bottlenecked by pci 2.0 even with GTX 880 ... unless i use 3 or 4 of them ?

as i remember PCI 2.0 was relesed in 2007 and bottlenecked only in 2011 with 480 ... bottlenecked but by a little

 

[tynopik]

all in favor of banning the word 'bottlenecked' say 'Aye!'

 

[brandon888]

all in favor of banning the word 'bottlenecked' say 'Aye!'

http://www.legitreviews.com/article/1921/3/


here is X79 system and card operates with pci 3.0 ;/

 

[SunnyD]

i have I7 3930K with Asus P9X79 .... my mobo supports pci 3.0 but cpu not ..it's a marketing trick as i understand cause there is no single cpu on 2011 socket that supports Pci 3.0 ....

Wow, this was answered for you this morning and you're still trying to rant misinformation about it?

 

[Deders]

so you mean taht Memory bandwidth of GPU has nothing to do with PCI bandwidth ? Then what a specification of GPU is sensitive to PCI bandwidth ? I hope you understand my question

I mean ... can i understand will or will not bottleneck PCI 2.0 My GPU if i jsut look at GPU specifications ... and if yes then how ? or there is a only way to wait for reviews to see difference ?

The PCIe bandwidth only affects how much data can be transferred to and from the graphics card, once it is on the card it is stored in the graphics memory which has a much higher bandwidth. Pretty much any single gpu will be happy with PCIe 2.0, so long as it has enough memory on board to store all the data it needs.

 

[brandon888]

The PCIe bandwidth only affects how much data can be transferred to and from the graphics card, once it is on the card it is stored in the graphics memory which has a much higher bandwidth. Pretty much any single gpu will be happy with PCIe 2.0, so long as it has enough memory on board to store all the data it needs.

http://www.anandtech.com/show/5264/sandy-bridge-e-x79-pcie-30-it-works


seems like X79 has PCI 3.0 ;/ but some people said it does not .... for example moonbogg .... he said that his 2 670 s run on pci 2.0 wtf then ?

 

[Deders]

What CPU do you and he have?

 

[brandon888]

What CPU do you and he have?

i have I7 3930K with Asus P9X79.... so can i use pci 3.0 ? how i can't hande GTX 880 if it will be 20% faster then 680 sli ... when on benchmarks I7 3930K handles 2 GTX 690 .... not by 100% sure but can handle 3 X 680 for sure ...

 

[brandon888]

http://www.xbitlabs.com/articles/cpu/display/core-i7-3960x-3930k_4.html

Six-core processors for enthusiasts are finally migrating to Sandy Bridge microarchitecture. And in the process they acquire quad-channel memory controller, integrated PCI Express 3.0 controller and extensive overclocking-friendly functionality. Are these innovations enough to help them set new performance records?


im confused from different answers .... some people say 2011 CPU s don't have pci 3.0 ... some say yes .... same with information from sites ....

 

[Erenhardt]

PCI has no memory.
If you asking about SSD - PCIe 2.0 can handle every SSD there is. 2.0 has 500MB/s per lane bandwidth. PCI SSD have around 1,5 GB/s transfer and are pluged into x4 lane. x4 lane gives you 2GB/s transfer both ways. So there is not much to be worried.
If you asking about GPU...
PCI badwidth is limited to some degree. None of the current GPUs can use more than half of what PCI has to offer. It is not about GPU, GDDR speed. There are other parts of your PC that will bottleneck. You SSD can't read enough data to fill PCIe bandwidth. GPU memory bandwidth is used mainly internally by GPU core - data is transfer via PCB.

And those: "With this SLI/CROSSFIRE PCIe will be bottleneck...." Think about that for a second. PCIe bandwidth is "per lane". It is point-to-point connection. No sharing in case of multiple PCIe devices. You can stack 4 GPUs, 6 SSDs, Gb Ethernet and whatever other PCIe device you have, and there will be no change. They work independly.

 

[brandon888]

PCI has no memory.
If you asking about SSD - PCIe 2.0 can handle every SSD there is. 2.0 has 500MB/s per lane bandwidth. PCI SSD have around 1,5 GB/s transfer and are pluged into x4 lane. x4 lane gives you 2GB/s transfer both ways. So there is not much to be worried.
If you asking about GPU...
PCI badwidth is limited to some degree. None of the current GPUs can use more than half of what PCI has to offer. It is not about GPU, GDDR speed. There are other parts of your PC that will bottleneck. You SSD can't read enough data to fill PCIe bandwidth. GPU memory bandwidth is used mainly internally by GPU core - data is transfer via PCB.

And those: "With this SLI/CROSSFIRE PCIe will be bottleneck...." Think about that for a second. PCIe bandwidth is "per lane". It is point-to-point connection. No sharing in case of multiple PCIe devices. You can stack 4 GPUs, 6 SSDs, Gb Ethernet and whatever other PCIe device you have, and there will be no change. They work independly.

Agree ! bottleneck in sli sounds strange .... even on tri quad and ect ...so if even half of pci 2.0 is not used yet ....then i think even 800 series will be fine with it .... so i cant calculate it from GPU-z for example ? i can see texture filtrate , memory bandwidth , pixel filtrate .... can caulculate from that specifications when will be pci 2.0 bottleneck or it is impossible ?

 

[ShintaiDK]

Remember LGA2011 got 40 PCie lanes on the CPU. LGA1155 only got 16.

So on LGA2011 you will still run full x16 with 2 cards. On LGA1155 you will run each card with x8.

A GTX880 or whatever it will be called will work fine in a PCIe 2.0 slot. Even today you can run a GTX680/HD7970 in a PCIe 1.1 slot and only lose 1%.

 

[brandon888]

Remember LGA2011 got 40 PCie lanes on the CPU. LGA1155 only got 16.

So on LGA2011 you will still run full x16 with 2 cards. On LGA1155 you will run each card with x8.

A GTX880 or whatever it will be called will work fine in a PCIe 2.0 slot. Even today you can run a GTX680/HD7970 in a PCIe 1.1 slot and only lose 1%.

em ... sorry but as i know 7970 run about 98-100% on pci 2.0 8X .. is that same as pci 1.1 16 X ? if yes then well Great .. im safe at least 3-4 years ....


and you mentioned 40 lanes .. i noticed it to ... so hope it will help .. thank you .. your forum is very helpful