PCIe cards backwards compatiblity with older motherboards

[rahba]

Are newer PCI-E cards compatible with older first generation PCI-E motherboards?

I bought a new Radeon 5770 but I wanted to hold off on buying a new motherboard+cpu. I know the CPU will be the bottleneck but I wanted to at least play all the old SM 3.0 games I couldn't with my x800. Unfortunately it won't POST in my PC but will POST in my friends newer PC.

The motherboard is a Gigabyte K8NF-9 (nforce 4) with an Athlon 64 X2 4400+. The PSU is an Antec TruePower 2.0 550 Watt (TPII-550) which is listed as being certified for the 5800 series.

 

[happy medium]

yes it should work fine in that board.

Where did you buy a 5770?

Welcome to Anandtech by the way.

Make sure the card is seated properly.
Make sure you have the extra pci-e power connector connected.
Clean all Ati drivers out with driver cleaner.

 

[rahba]

Thanks for the welcome. I hate for my first post on here to be a "help me with my computer problems" but it's driving me nuts. Bought the card from http://www.canadacomputers.com , I guess they broke the street date.

To be clear when I say it won't POST, I mean, I turn on the power, the fans spin, blank screen, no beep error codes.

Things I've tried:

-using a different 6 pin power connector for the graphics card
-using the pci-e adapter and connecting to a standard molex
-using a 5750 my friend had purchased at the same time (this won't POST either, works fine in his rig)
-BIOS is updated to latest version
-reseating the card countless times
-removing the card (with the card removed I get the appropriate beep code explaining that)
-connecting my old x800 (works fine so at least I didn't break anything)
-disconnecting everything (harddrives, case fans, dvd drive) and only connecting power cables to the motherboard and the video card

If it's not the PCI-E compatibility thing, am I right to assume it's gotta be the PSU?

 

[happy medium]

I did a little google searching and it looks like with certain cards pci-e 1.0a (which I believe is what your board has) is not allways backwards compatible with the latest pci-e 2.0 cards.

Your psu is more than enough.

Sorry.

I believe pci-e 1.1 is allways compatible.
Mabe someone else can confirm this?

 

[happy medium]

Heres some evidence.

http://forums.anandtech.com/me...id=31&threadid=2156173

Seems a bios flash will help with some of these problems . Try the forums for your motherboard, I'm sure others have had this problem.


Ah....... try to update your chipset drivers.!

 

[tcsenter]

There are only a handful of particular scenarios where PCI-E 2.0 graphics card would not work on a motherboard with a PCI-E 1.0 chipset, and it was more of an interoperability issue, not a "compatibility" issue. This was almost exclusively limited to VIA chipsets and a cohort of older NForce 4 motherboards with a buggy BIOS.

There are cases involving older motherboards based on Intel 915 and ATI RS482/485 as well, but this only affects the HDMI audio controller that is integrated on newer PCI Express graphics cards (e.g. Radeon 3000 and higher, GeForce 9 and higher), not the actual graphics. IOW, the graphics work fine, just the onboard HDMI audio controller won't function.

 

[rahba]

This article says different:

http://www.techpowerup.com/rev...70_PCI-Express_Scaling

"Another important point to make is that PCI-Express is forward and backwards compatible. You can run any PCI-E 1.x card in a 2.0 slot or any 2.0 card in any 1.x slot, with reduced bandwidth of course."

Can anyone verify this? Is anyone else running a relatively new pci-e card in an older pci-e motherboard?

edit: wrote this before tcsenter's reply

 

[tcsenter]

If its not the PSU, then its either:

- Buggy motherboard BIOS
- Buggy VGA BIOS
- Some idiosyncratic glitch between the two (e.g. ATI's new PowerPlay implementation or something)

I found one GA-K8NF-9 user report successfully running HD 4770 without incident. Idiosyncratic interoperability glitches happen. These are the things that motherboard BIOS updates are for. The bigger problem is that your motherboard is no longer being supported, so you may not get a fix if either ATI or the manufacturer of your HD 5770 doesn't feel the problem is with their card or VGA BIOS.

Apparently some Radeon HD 4870 X2 boards featured a small DIP switch or jumper to force the PCI-E mode from 2.0 to 1.x. e.g.

http://www.cfd.co.jp/vga/images/radeonhd4870x2_sw1.jpg

Maybe your board has one like it. Probably not, but its worth looking. Not entirely sure which one controls the PCI-E mode, but one of them is supposed to.

 

[Vilanova]

First of all, sorry for resurrecting this old post guys... but I have a similar question related to this graphic card and another PCIe1.0a motherboard: http://www.asrock.com/mb/overview.asp?Model=ALIVEDUAL-ESATA2

I've looked through the internet and made a wide research about this mobo and its compatibility (or interoperability as tcsenter suggested) with PCIe 2nd gen cards and had no luck a part from some incomplete reports...

Is there any way (besides of buying and testing) to be 99.99 per cent sure that it will work?

I have already contacted Asrock support team for more information, and got no reponse for the moment... August may be not a suitable month for answering customer's questions...

Any help please?