Incompatibility between PCI-E 2.0 videocards and PCI-E 1.0/1.0a motherboards

[BernardP]

I have a motherboard with integrated graphics and an empty PCI Express 16X slot. It conforms to the PCI-E 1.0a standard. I am planning on adding a discrete videocard soon. As all the new cards are now PCI-E 2.0 and this is supposedly compatible with earlier versions of PCI-E, I had assumed that a new videocard would be compatible with my motherboard. However, I found out that things are not so simple.

First, I accidentally found this on the Wikipedia NVidia 8 Series page:

Shortly after the release, an incompatibility issue with older PCI Express 1.0a motherboards was unmasked. When using the PCI Express 2.0 compliant 8800GT in motherboards with PCI Express 1.0a slots, the card would not produce any display image, but the computer would often boot (with the fan spinning at a constant 100%).(...) In relation to this compatibility issue, the high numbers of DOA (Dead On Arrival - cards that are broken out of the box) (As much as 13-15%) were believed to be inaccurate. When it was revealed that the G92 8800GT and 8800GTS 512Mb were going to be designed with PCI Express 2.0 connections, NVIDIA claimed that all cards would have full Backwards-Compatibility, but they completely failed to mention that this was only true for PCI Express 1.1 motherboards.

Looking for confirmation, I found more info on XBit Labs:

First, in their review of the 8800GT:

Although PCI Express 2.0 cards are compatible only with mainboards with PCI Express 1.1 and higher, our GeForce 8800 GT worked on an ASUS A8R32-MVP Deluxe (ATI CrossFire Xpress 3200) which only supports PCI Express 1.0a

So they noted an exception to the incompatibility issue.

Then , they touch the subject again in their review of the 3850 and 3870:

Like with Nvidia GeForce 8800 GT, we can expect some incompatibility with certain mainboards supporting PCI Express 1.0/1.0a. The lack of such problems is guaranteed for PCI Express 1.1 mainboard only.

When they reviewed the more recent 9600GT though, X Bit Labs didn't mention this potential issue.


I would like to know if some of you have found more info about this issue, as the only workaround mentionned seems to be to reflash the videocard BIOS, thus voiding the warranty.

Do you have experience with installing a PCI-E videocard on a mobo only supporting PCI-E 1.0 or 1.0a?

Thanks

 

[Auric]

PCIe 1.0 is dead. Just upgrade... to AGP.

 

[BernardP]

Originally posted by: Auric
PCIe 1.0 is dead. Just upgrade... to AGP.

Of course it's dead. A bit frustrating as my motherboard was a newly-launched product just 2 years ago. I am planning on keeping it for a couple more years. Only trying to determine if I should get a PCI-E 1.1 card while I still can.

 

[Auric]

Originally posted by: BernardP



Of course it's dead. A bit frustrating as my motherboard was a newly-launched product just 2 years ago. I am planning on keeping it for a couple more years. Only trying to determine if I should get a PCI-E 1.1 card while I still can.

Odd, my mobo is five years old and has never suffered a compatability issue despite being continually upgraded with various parts including HDDs, ODDs, sound cards, and of course video cards.

If the mobo and chipset are from reputable companies I would have faith that a BIOS update will overcome the issue (if not from the graphics co.). It would indeed be rather frustrating otherwise. Good luck getting it worked out and hope that if it does, that it won't be necessary again with any future upgrade 'cause at some point these co.'s will simply deny liability and support.

 

[ajaidevsingh]

Originally posted by: BernardP
I have a motherboard with integrated graphics and an empty PCI Express 16X slot. It conforms to the PCI-E 1.0a standard. I am planning on adding a discrete videocard soon. As all the new cards are now PCI-E 2.0 and this is supposedly compatible with earlier versions of PCI-E, I had assumed that a new videocard would be compatible with my motherboard. However, I found out that things are not so simple.

First, I accidentally found this on the Wikipedia NVidia 8 Series page:

Shortly after the release, an incompatibility issue with older PCI Express 1.0a motherboards was unmasked. When using the PCI Express 2.0 compliant 8800GT in motherboards with PCI Express 1.0a slots, the card would not produce any display image, but the computer would often boot (with the fan spinning at a constant 100%).(...) In relation to this compatibility issue, the high numbers of DOA (Dead On Arrival - cards that are broken out of the box) (As much as 13-15%) were believed to be inaccurate. When it was revealed that the G92 8800GT and 8800GTS 512Mb were going to be designed with PCI Express 2.0 connections, NVIDIA claimed that all cards would have full Backwards-Compatibility, but they completely failed to mention that this was only true for PCI Express 1.1 motherboards.

Looking for confirmation, I found more info on XBit Labs:

First, in their review of the 8800GT:

Although PCI Express 2.0 cards are compatible only with mainboards with PCI Express 1.1 and higher, our GeForce 8800 GT worked on an ASUS A8R32-MVP Deluxe (ATI CrossFire Xpress 3200) which only supports PCI Express 1.0a

So they noted an exception to the incompatibility issue.

Then , they touch the subject again in their review of the 3850 and 3870:

Like with Nvidia GeForce 8800 GT, we can expect some incompatibility with certain mainboards supporting PCI Express 1.0/1.0a. The lack of such problems is guaranteed for PCI Express 1.1 mainboard only.

When they reviewed the more recent 9600GT though, X Bit Labs didn't mention this potential issue.


I would like to know if some of you have found more info about this issue, as the only workaround mentionned seems to be to reflash the videocard BIOS, thus voiding the warranty.

Do you have experience with installing a PCI-E videocard on a mobo only supporting PCI-E 1.0 or 1.0a?

Thanks

My friend is is useing a 3870 X2 with his old ATI m/b with a single 16X PCIE slot that is 1.0 (Not even 1.0a), We did note there was a slight performance drop.

 

[BernardP]

Originally posted by: ajaidevsingh

My friend is is useing a 3870 X2 with his old ATI m/b with a single 16X PCIE slot that is 1.0 (Not even 1.0a), We did note there was a slight performance drop.

So it's working. Great! I am trying to see if the incompatibility problem is systemic, or just an occasional occurence. Looks like a crapshoot.

 

[Auric]

Originally posted by: BernardP

Originally posted by: ajaidevsingh

My friend is is useing a 3870 X2 with his old ATI m/b with a single 16X PCIE slot that is 1.0 (Not even 1.0a), We did note there was a slight performance drop.

So it's working. Great! I am trying to see if the incompatibility problem is systemic, or just an occasional occurence. Looks like a crapshoot.

Well, the issue seems to be with Nvidia, not AMD/ATI cards. The latter reportedly start in 1.0 mode and then switch to 2.0 as available. ATI likewise has a neat solution to dodgy AGP implementations with SmartGart which automatically tests for compliance and drops back if necessary.

 

[Encke]

I have a Gigabyte GA-M61P-S3 mobo (1.0a slot) here and the 8800gt I bought (Zotac) works fine. I am pretty sure it is running at its rated speed with no dropoff but this is the only computer I have so I can't compare it to a different one with newer hardware to be sure. That being said depending on the situation I guess the card should run fine even on a 1.0a (at least.. not sure about 1.0) since I'm pretty sure none of the current cards need nor use all the extra bandwidth 2.0 provides. Also my memory is bad so forgive me if I make a mistake (not uncommon for me) but I believe the issue with 2.0 gpu's and 1.0 slots was mainly happening to people with 8x slots instead of 16x and possibly to people who had more than one PCI-E slot but different versions (a 1.1 slot and a 1.0/1.0a slot). Either that or 1 of the slots was 8x and the other full speed which caused issues in SLI mode (and maybe with just 1 card).. it was something like that though. I know I read about an issue like that somewhere but I'm too lazy too look it up again now. Anyway if you are still concerned about it you could try asking the manufacturer of your mobo about it and see what they say. Thats what I did when I got tired of looking for information on it and not knowing what to believe. They ended up telling me it should work fine though it was broken english and kinda hard to understand at first.

 

[darckhart]

I have an abit ip35pro and this was a hit or miss problem between v1.0 and v1.1 mobos and different mnfrs' implementation of the pcie compatibility on 8800gt cards. Some boards had 1.0 and 1.1 support. Others had 1.0 and 1.0a support etc. Some cards played well and some didn't. You really need to check with your mnfr tech support or support forums to be sure.

You can check out the abit thread here if you're interested: http://forum.uabit.com/showthread.php?t=131643&page=1

 

[driftwood07]

i have a 8800gt pcie 2.0 card and an asus a8v-e deluxe pci-e 1.0 board . i was dissapointed to find out that the two are incompatable and the card shows no picture .this was after being told that pci2.0 cards were compatable with 1.0 boards, and for the most part they are , i just got unlucky with mine , so my 8800gt sits in a box till i upgrade my entire system \ :

 

[Auric]

Originally posted by: driftwood07
i have a 8800gt pcie 2.0 card and an asus a8v-e deluxe pci-e 1.0 board . i was dissapointed to find out that the two are incompatable and the card shows no picture .this was after being told that pci2.0 cards were compatable with 1.0 boards, and for the most part they are , i just got unlucky with mine , so my 8800gt sits in a box till i upgrade my entire system \ :

Why not return it for a refund then or at least sell it rather than suffer devaluation while not even getting any use out of it?

 

[Martimus]

I have a HD 3850 (which is PCI-e 2.0) running on my ECS KN1 Extreme, which has PCI-e 1.0, and it works fine.

 

[BernardP]

Reading comments here and the Abit forum link from darckhart, it seems to be hit or miss, but mostly hit. Here is something interesting from the Abit forum:

Cut and Paste from ASUS FAQ's

?This motherboard comes with the support of different PCI express specification on different PCI express slots. The PCIEX16_1 slot has been designed based on PCI express 1.1 specification, while PCIEX16_2 slots adopts PCI express 1.0/1.0a specification. As PCI express 1.0/1.0a standard is not compatible with PCI express 2.0 specification, installing PCI express 2.0 cards onto PCIEX16_2 slot will result in system fail to detect expension cards installed on both PCIEX16_1 and PCIEX16_2 slot.

Hmmm... It seems that 2.0 cards are not compatible with 1.0/1.0a slots, but they might work anyway. But if they don't work, it is normal, as they are not compatible :roll:

 

[PCTC2]

check my sig. 680i w/ 8800 GTS 512 MB. Works perfectly

 

[andylawcc]

my Biostar Nforce 570SLI mobo should be PCI-E 1.0 and a 9600GT worked just fine.

 

[Auric]

Originally posted by: BernardP
Cut and Paste from ASUS FAQ's
...

Why the fark would they make a board with a 1.1 primary slot and 1.0 secondary? Did that somehow save five cents? For shame ASUS.

 

[thestain]

Ok.. all previous cards until just new manufactured ones have worked well in my systems, but I just posted about my new MSI GeForce 8600 GT that looks different from pic on newegg, that now no longer shows pic and on its site does black screens in windows and the new EVGA 8800 GS black screens as well.. this is on the MSI K8NGM2-FID and will test on other boards, but... these cards work fine in bios, dos and linux. So could this be something other than motherboard compatibility.. windows xp pro sp 2 and black screen.. sp2 black screens on my Asus A8N-SLI Premium, but my Asus A8R-32 MVP board with SP1 displays things ok.. so could this be more than meets the eye?

Has anyone else tested in linux, because these newer pci-e 2.0 cards work fine for me in linux regardless of motherboard, while they black screen in windows XP.

The Stain

 

[BernardP]

Originally posted by: thestain
Ok.. all previous cards until just new manufactured ones have worked well in my systems, but I just posted about my new MSI GeForce 8600 GT that looks different from pic on newegg, that now no longer shows pic and on its site does black screens in windows and the new EVGA 8800 GS black screens as well.. this is on the MSI K8NGM2-FID and will test on other boards, but... these cards work fine in bios, dos and linux. So could this be something other than motherboard compatibility.. windows xp pro sp 2 and black screen.. sp2 black screens on my Asus A8N-SLI Premium, but my Asus A8R-32 MVP board with SP1 displays things ok.. so could this be more than meets the eye?

Has anyone else tested in linux, because these newer pci-e 2.0 cards work fine for me in linux regardless of motherboard, while they black screen in windows XP.

Hey thestain, you have the same motherboard as I. Did the 8600GT and 8800GS work correctly in Windows previously? 8600GT and 8800GS (AFAIK) are PCI-E 1.1 and not 2.0. So you problem should not be related to PCI-E 2.0 backward compatibility.

 

[Engineer]

NVidia has released reference BIOS 62.92.24.xx.xx (or newer by now) for the 8800GT series that resolves some of the incompatiblilties between the card and the PCIe slot. Not sure if all have been resolved, but many work fine with that BIOS or better. This is especially a problem with some of the VIA chipset boards (that's why I'm waiting on MSI tech support to send me an updated BIOS for my 8800GT OC card to work with my Asrock 775Dual-VSTA board).

Lots of information here (long thread).

 

[humanure]

My 3870 runs fine on my ab9 quad gt, 1.0a slot

 

[BernardP]

I think I might have finally gone to the bottom of this. PCI-SIG or Peripheral Component Interconnect Special Interest Group is the industry consortium responsible for the PCI and PCI Express specifications.

Digging on their web site, I found some information on the PCI Express® 2.0 FAQ's Page

There are specific statements about backwards compatibility:

The PCIe Base 2.0 specification supports both 2.5GT/s and 5GT/s signaling rates, in order to retain backward compatibility with existing PCIe 1.0 and 1.1

The PCIe Base 2.0 specification supports both the 2.5GT/s and 5GT/s signaling technologies. A device designed to the PCIe Base 2.0 specification may support 2.5GT/s, 5GT/s or both. However, a device designed to operate specifically at 5GT/s must also support 2.5GT/s signaling

I don't see how this can leave room for PCI-E 2.0 not to be compatible with PCI-E 1.0 if the specifications are adhered to.

So it appears that if some PCI-E 2.0 videocards are incompatible with some PCI-E 1.0 motherboards, it's because of an incorrect/incomplete implementation of the PCI-E 2.0 specification in the videocard, or a motherboard that doesn't fully conform to the PCI-E 1.0 specification.