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Modding a PCI-E 16x card to work in a 1x slot AND in a 16x slot |
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Practice, Conclusions
The Practice
First up, the victim:
A dirt cheap 16mb 6200TC. A surprisingly good card considering it’s more crippled than a Williamette Celeron. In BF2 it was able to maintain a quite respectable 60+ frame rate in low detail, 800x600. 1024 wasn’t totally horrible either.
The test rig will be my current system. An A8NSLI-Deluxe, 2gb of decent ram, A64 3000+, a 6800GT and various other specs.
Initially, I test it in the top 16x slot, with the SLI board set to single card. Yep, it starts off working.
Nothing suprising there. I haven’t butchered it yet. Then I wondered, does it work at 8x? So I switched the SLI card.
And 8x in the second slot.
Now to test the theory. The SLI board was returned to “single card” and the 6200 taped up. Lane 2 was covered and the card inserted. There’s no pictures because the tape was transparent and the camera not that great.
15x doesn’t work. It seems that either the card, chipset or bios have a limitation that they will ONLY run with lanes next to each other starting from 1x. Personally, I suspect it’s a bios limitation. The PCI-E standard is quite flexible. It should have automagically negotiated for 15 lanes and continued as normal.
But it does at least work. The rest of the lanes were taped up (3-16) and the computer booted. No display.
After a bit of head scratching, I turned to the pcie pinouts. Pin 81B “Hot plug present detect” caught my attention. The tape was removed, allowing 81B and both 82 pins to make contact. It worked. Still at 1x, but nonetheless, it worked. At this point, I suspect the card itself will not power on until 81B is connected.
Anyhow, there’s nothing left for me to do. Time to hack it up.
It looks good. Lane 2 is totally removed and all visible trace wires were avoided.
And it fits nicely.
Unfortunately, that’s it. The card no longer works. After testing in both 1x and 16x slots, I have come to the conclusion that I must have cut an internal trace wire.
RIP 16mb 6200TC.
Conclusion
Ever since reading about the dual slot 1 Celeron mod, I’ve wanted to create an insane hardware mod. Well, I’ve done it. It doesn’t work, but I’m convinced that it should work and that I screwed up the cut. While my individual card failed, I hope that my failure could perhaps promote stock 15x cards, correct PCI-E auto-negotiation to allow non-contiguous lane usage, just plain 1x cards or even half height cards with optional 16x to 1x adaptors.
Feel free to discuss this article in this thread.
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