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PCI Express 2.0 x16: (2x8) or (x16, x8, x4)... What's the difference?

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February 11, 2012 5:33:32 AM

Well boys, it looks like Gigabyte has once again taken a hot dump all over my face.

I'm going to have to return the board I just bought and pay a little more for one with lower specs.

Current Board:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Best Alternative:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...


So what kind of loss am I going to be taking here? I'm focusing on the PCI E aspect. How's (2x8) different from (x16, x8, x4) and most importantly, how's it going to affect my graphics card? It's a EVGA SuperClocked GTX 560 TI DS.




The board I bought works perfectly fine (outside of most games). However about 30-40% of the time when I launch a game the mouse pointer is completely off and totally unusable. If I actually make it into the game, it'll sometimes make the pointer so slow it takes about two 1ft swipes to turn 90 degrees.

The troubleshooting's over with. It's been narrowed down to the board. Tried different mice, reformatting, flashing BIOS, updated GPU - tried both NVIDIA and EVGA drivers, and sitting on the phone with Gigabyte for an hour playing with the BIOS with no success.

Sucks.

So am I gonna lose GPU quality?

February 11, 2012 6:01:36 PM

...also noticed it has eSata and Firewire... what do you actually use those for?
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February 11, 2012 6:07:34 PM

flossbandit said:
...also noticed it has eSata and Firewire... what do you actually use those for?

Before USB 3.0 a lot of external hard drives used those interface ports to exchange files. They're supposedly each much faster than USB 2.0

They're being pretty much replaced by USB3, but since a lot of people still use the old ports many motherboards still come with them. I never really did like eSATA... first time I tried it it caused my whole computer to lag like crazy and nearly crashed my comp. The only way I could use it was if I shut off everything else and didn't touch my computer for the entire duration of the file transfer. It might have been a problem with something else like the hard drive or the motherboard instead of the eSATA port, but I never did track it down. All I know is that I'm going to stick with USB3 from now on.

I've never tried Firewire personally, so I don't have any valid opinion regarding it.
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February 11, 2012 7:27:19 PM

PTNLemay said:
Before USB 3.0 a lot of external hard drives used those interface ports to exchange files. They're supposedly each much faster than USB 2.0

They're being pretty much replaced by USB3, but since a lot of people still use the old ports many motherboards still come with them. I never really did like eSATA... first time I tried it it caused my whole computer to lag like crazy and nearly crashed my comp. The only way I could use it was if I shut off everything else and didn't touch my computer for the entire duration of the file transfer. It might have been a problem with something else like the hard drive or the motherboard instead of the eSATA port, but I never did track it down. All I know is that I'm going to stick with USB3 from now on.

I've never tried Firewire personally, so I don't have any valid opinion regarding it.


Good to know. Any idea on the PCI E stuff?
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February 11, 2012 7:59:04 PM

Not much experience on that end... but I'm not sure what you mean by your original question. Both those boards seem to have the same thing, double PCIe 2.0 x16 slots, so... aren't they the same? In that sense there wouldn't be any trade down, no? Well... the Gigabyte one does have three of them, but from the way they're placed I don't think you could use them in a triple card configuration. Don't quote me on that one though.

I know sometimes an x16 slot will have to dumb itself down when it's engaging in an SLI or Crossfire bridge with an x8 slot, but they tell you that when it happens. And yeah... both these seem to have double x16, so I don't think that would be an issue.
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a c 717 V Motherboard
February 11, 2012 8:22:38 PM

All LGA 1155 have x16 PCIe native GPU lanes, that get split up into x16 and x8/x8 for SLI/CF. In the case where you see (x16, x8, x4):
1. (single GPU) - x16 represents x16 lanes of PCIe 2.0 to a single GPU and the x4 additional PCIe lanes for some other device without being a direct path the the CPU's GPU's lanes. So in actuality it's x16/x0/x4
2. (dual GPU's) - the x16 lanes are split (switch GEN2 or GEN3) into x8 PCIe GPU1 + x8 PCIe GPU2, and the x4 is same as above (#1). So in actuality it's x8/x8/x4

The only difference in the GEN2 vs GEN3 is the secondary PCIe speed, in most cases the primary PCIe with run at whatever PCIe version is supported by the CPU. The current SB Sandy Bridge is PCIe v2.x and the upcoming IB Ivy Bridge supports PCIe 3.x.

No getting to you problem MOBO, it's really not designed to be a high OC'ing MOBO and if the temps are high then I suspect either a bad OC i.e. too high of vCore keep in under 1.35v, poor cooling HSF, or my best guess is a small and restrictive case. If it's the GPU over heating then keep it at stock or rated OC and again poor airflow. If you have a problematic, failing PSU and or including too small then you can also get unexpected behavior including component failure(s).
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February 11, 2012 8:30:55 PM

jaquith said:
All LGA 1155 have x16 PCIe native GPU lanes, that get split up into x16 and x8/x8 for SLI/CF.

So even Ivy Bridge won't be able to run 2 graphic cards at x16 simultaneously? It has to go x8/x8 even with that new fancy-pants Z77 chipset coming out later this year?
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a c 717 V Motherboard
February 11, 2012 8:48:43 PM

The LGA 1155 IB is still x16 lanes, the only difference is that it 'can' run PCIe v3.0 (double bandwidth) -- if the CPU, GPU and MOBO offer PCIe 3.x; it's all or PCIe 2.x.

What I expect to see is the same as I've seen with the P67/Z68 the addition of some form of 'NF200' chipset to allow additional (pseudo) lanes to support 3-WAY SLI/CF, but it's still like a 'funnel' going back to the IB CPU -- 16 lanes.

Meaning, today you can run x16/x16 on LGA 1155 with the addition of an NF200 chipset and it's added x16 lanes. In theory you could run x4/x4/x4/x4 PCIe 3.x which is the exact same bandwidth of PCIe 2.x x8/x8/x8/x8 -- and PCIe 3.x x8/x8 is the same as PCIe 2.x x16/x16.

PCIe + CPU -> http://www.tomshardware.com/reviews/p67-gaming-3-way-sl...
PCIe 2.x vs 3.x -> http://www.hardwarecanucks.com/forum/hardware-canucks-r... ; I still haven't seen anything suggesting 2~4 WAY is any different.

So who knows what wacky lane setup some MOBO's will have, but I suspect no difference and even the IB/LGA 1155 will be limited to 2-WAY and 3-WAY SLI.

Frankly, there's NO GPU out there that fully saturates PCIe 2.x x8 even with the multi-core GPU's. It will be IMO YEARS before any GPU touches full saturation of PCIe 2.x x16 lanes and laughable PCIe 3.x x16 (decade or longer).
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February 11, 2012 9:59:54 PM

jaquith said:
All LGA 1155 have x16 PCIe native GPU lanes, that get split up into x16 and x8/x8 for SLI/CF. In the case where you see (x16, x8, x4):
1. (single GPU) - x16 represents x16 lanes of PCIe 2.0 to a single GPU and the x4 additional PCIe lanes for some other device without being a direct path the the CPU's GPU's lanes. So in actuality it's x16/x0/x4
2. (dual GPU's) - the x16 lanes are split (switch GEN2 or GEN3) into x8 PCIe GPU1 + x8 PCIe GPU2, and the x4 is same as above (#1). So in actuality it's x8/x8/x4

The only difference in the GEN2 vs GEN3 is the secondary PCIe speed, in most cases the primary PCIe with run at whatever PCIe version is supported by the CPU. The current SB Sandy Bridge is PCIe v2.x and the upcoming IB Ivy Bridge supports PCIe 3.x.

No getting to you problem MOBO, it's really not designed to be a high OC'ing MOBO and if the temps are high then I suspect either a bad OC i.e. too high of vCore keep in under 1.35v, poor cooling HSF, or my best guess is a small and restrictive case. If it's the GPU over heating then keep it at stock or rated OC and again poor airflow. If you have a problematic, failing PSU and or including too small then you can also get unexpected behavior including component failure(s).


I don't really think airflow's the issue. There are 8 fans total including the Hyper 212 plus heatsink. My case is pretty small but it's got a lot of mesh on it. It's also a new build, so I haven't overclocked anything yet & haven't seen the temps go above 44 degrees Celsius in Battlefield 3.

Case:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Thanks for breaking down the PCI E stuff. And just to dumb it down a little, you don't think the (2x4) thing will make a difference with the GPU, correct? I just saw the lower numbers on newegg and hesitated even though I had no idea exactly what they meant.
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a c 717 V Motherboard
February 11, 2012 10:12:30 PM

I read the 90 degrees and I misread as temps. Please post all you core components. I'm not sure what you mean by "(2x4)"; if you're running SLI then it's 2x8 and if you're seeing 2x4 in GPU-z then run some game or anything to place a load on the GPU(s) and look again. ;) 
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February 12, 2012 12:26:40 AM

jaquith said:
I read the 90 degrees and I misread as temps. Please post all you core components. I'm not sure what you mean by "(2x4)"; if you're running SLI then it's 2x8 and if you're seeing 2x4 in GPU-z then run some game or anything to place a load on the GPU(s) and look again. ;) 


Yeah, I can see how that'd be a little confusing with the degree thing.

Anyway, all I was asking is if there was a difference in the PCI E 2.0 x16 slots on the two boards, because newegg posts those different values beside them. I have absolutely no idea what they mean and was wondering if it would affect the way my graphics card works.

My Build:

CPU: i5 2500k

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

GPU: EVGA SuperClocked GTX 560 TI DS

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Mobo (That's getting returned): Gigabyte GA-Z68MA-D2H-B3

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

PSU: XION XON 700P12F

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

RAM: Wintec One 8GB (2x4) 1600Mhz

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

FAN / Heatsink: Cooler Master Hyper 212 Plus

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Case: In Win Dragon Slayer

http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Plus a pic about the original question... obviously the gigabyte has another slot (which would be useless with SLI because it's so close)...

but at this point i'm gonna go ahead and guess that whatever it is, it's not something that most people take into consideration and is possibly irrelevant.
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a c 717 V Motherboard
February 12, 2012 12:40:13 AM

Answer is no, they are both the same. I'm doing this on my iPhone so tomorrow I'll give you a more in depth answer if you need more info. Both MOBOs offer x16 single or x8/x8 in SLI. Frankly if not using the x4 PCIe slot go in the BIOS and either reduce the lanes or Disable if possible.

mATX offers limited choices so my first pick is the ASUS GENE and the the EVGA listed.
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February 12, 2012 1:41:13 AM

jaquith said:
Answer is no, they are both the same. I'm doing this on my iPhone so tomorrow I'll give you a more in depth answer if you need more info. Both MOBOs offer x16 single or x8/x8 in SLI. Frankly if not using the x4 PCIe slot go in the BIOS and either reduce the lanes or Disable if possible.

mATX offers limited choices so my first pick is the ASUS GENE and the the EVGA listed.


Well FML. I am defeated. Newegg's power search failed me as well. I just ordered that EVGA one a few hours ago. Had I even known of the ASUS GENE then that one would have probably taken the cake.

...........

BUT on second thought, I really don't see myself realistically using 32GB of RAM and it'll probably be time to buy another motherboard by the time PCI E 3.0 really catches on. So I feel a little better now.
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a c 717 V Motherboard
February 12, 2012 1:29:28 PM

I truely wish that ALL MOBO specs were less confusing and 'standardized' for the consumer. When new lines come out I too have to sift through specs and in many examples even the folks like me get confused and often even argue because of deliberate ambiguity. (NF200 MOBO's started a lot of arguments.) Example standardized: (x16/x0 + x4, x8/x8 + x4, 2-WAY SLI and 3-WAY CF). Then there would be no confusion.

Both the EVGA Z68 SLI Micro and ASUS Maximus IV Gene-Z/GEN3 are good MOBO's, the ASUS is fractionally better for OC'ing the CPU. PCIe 3.x vs 2.x (switch) means nothing with your i5-2500K and GTX 560 Ti's i.e. they perform on par with each other. In other words be happy!

NewEgg takes in a feed of 'data', the old saying 'garbage in garbage out' -- BUT nothing you've listed is anything but variations of 'good'.

Best of Luck and Enjoy! :) 
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February 12, 2012 7:01:31 PM

jaquith said:
I truely wish that ALL MOBO specs were less confusing and 'standardized' for the consumer. When new lines come out I too have to sift through specs and in many examples even the folks like me get confused and often even argue because of deliberate ambiguity. (NF200 MOBO's started a lot of arguments.) Example standardized: (x16/x0 + x4, x8/x8 + x4, 2-WAY SLI and 3-WAY CF). Then there would be no confusion.

Both the EVGA Z68 SLI Micro and ASUS Maximus IV Gene-Z/GEN3 are good MOBO's, the ASUS is fractionally better for OC'ing the CPU. PCIe 3.x vs 2.x (switch) means nothing with your i5-2500K and GTX 560 Ti's i.e. they perform on par with each other. In other words be happy!

NewEgg takes in a feed of 'data', the old saying 'garbage in garbage out' -- BUT nothing you've listed is anything but variations of 'good'.

Best of Luck and Enjoy! :) 



Thanks for sticking with me. I appreciate all the help. Best answer selected.
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February 12, 2012 7:01:48 PM

Best answer selected by FlossBandit.
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a c 329 V Motherboard
February 12, 2012 7:06:00 PM

This topic has been closed by Nikorr
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