@eddy02350:
When hard-modding, you have to check in the BIOS and make sure that the UEFI header strap doesn't override anything (i.e. the AND strap ID bits should all be 1, and OR strap ID bits should all be 0). It is possible that your hard-strap works fine, but your soft-strap is locked so modding the hard-strap won't touch (some of) the low 5 bits. Same goes for the straps in the BIOS part (as opposed to UEFI header part).
@mrkrad:
The driver has been scrambled ever since somebody modified them to make SLI work on non-Nvidia motherboards. Nvidia's reponse was to encrypt the drivers. Intel's response was to not give Nvidia a QPI licence so they couldn't make motherboard chipsets for Core i and later CPUs. Just deserts and good riddance - doubly so since Nvidia motherboard chipsets were eyewateringly buggy and unreliable. But the scrambled drivers, unfortunately, stuck.
@opoeta:
Kudos for putting adjustable resistors on there.
@Mikhail80:
Nobody has yet been able to restore the missing GL primitives on GeForce cards. Cross-flashing the BIOS, in the one case where it actually works (Q2000 BIOS onto a GTS450), doesn't seem to achieve anything obviously useful in this regard; then again, Q2000 and GTS450 are very, very similar, much more so than other GeForces are to their equivalent Quadros, with maybe the exception of a K5000/GTX680 4GB variants - in that they have the same amount of VRAM. I haven't tried flashing a full strap-adjusted K5000 BIOS onto my GTX680 yet - it is on my ever-growing TODO list.
In case of the GF106 GPUs (GTS450/Q2000) I suspect the missing functionality is cut out of the GPUs before packaging, and if that is the case, the chances of restoring this are non-existant.
Note, however, that modifying a GTS450 into a Quadro 2000 does produce
some performance benefits - Maya scores, although still far behind a real Quadro 2000, go up by around 40% after modifying the card. In case of the GTX470/Q5000 and GTX480/Q6000 mods, there are also other performance improvements, to be gained, such as enabling the second DMA channel (DMA transfers become bidirectional rather than unidirectional), which can significantly boost DMA transfers to/from the GPU, depending on the workload you are throwing at it.
Unfortunately, the same improvements do not hold in case of GTX580/Q7000 mod - all results remain exactly the same on that. Other people have reported similarly unchanged results on later GPUs. There also appear to be no bidirectional DMA capabilities on the newer GPUs.
General update:
I have just spent a few hours messing about with a GTX470/Q5000 BIOS modding, and one thing that seems quite certain at the moment is that a GTX470 will not work with a strap-modded Q5000 BIOS. The machine boots, but graphical output is corrupted when not in text mode (at least in Windows), and as far as I can make out GPU-Z isn't showing the card's capabilities properly (e.g. 0MB of RAM). I suspect a major part of this is down to the fact that a Q5000 has 2x the RAM of a GTX470, but I have not been able to establish where the memory size is stored in the BIOS by looking at things like very similar GTX580 cards that have the same BIOS version number but different RAM size (e.g. MSI produced GTX580s with 1.5 and 3GB of RAM which have the same BIOS version numbers). I narrowed the BIOS differences down to 5 possible locations (I think) by excluding things like the board, boot string, and checksum related differences, but it is not at all obvious whether the memory size is even encoded in the BIOS, let alone how.
If anyone cares or is interested in investigating further, the full hex diff between the 1.5 and 3 GB card variants is here:
$ diff <(xxd MSI.GTX580.1536.110715.rom) <(xxd MSI.GTX580.3072.110504.rom)
4c4
< 0000030: 0100 0000 c000 8d4e 3037 2f31 352f 3131 .......N07/15/11
---
> 0000030: 0100 0000 c000 8d4e 3035 2f30 342f 3131 .......N05/04/11
6c6
< 0000050: e986 2a00 6214 6025 ffff ffff 0000 0000 ..*.b.`%........
---
> 0000050: e986 2a00 6214 6225 ffff ffff 0000 0000 ..*.b.b%........
12c12
< 00000b0: 3136 3100 0000 0000 0000 0000 0000 0000 161.............
---
> 00000b0: 3133 3000 0000 0000 0000 0000 0000 0000 130.............
1189c1189
< 0004a40: 0000 1f01 0000 0023 6220 0300 3313 2003 .......#b ..3. .
---
> 0004a40: 0000 1f01 0000 0023 6230 0300 3313 2003 .......#b0..3. .
1191,1192c1191,1192
< 0004a60: 7f07 0000 008f 0000 0000 9f01 0000 00af ................
< 0004a70: 0200 0000 bf03 0000 00cf 0400 0000 df05 ................
---
> 0004a60: 7f07 0000 008f 0000 0000 9f01 0000 00a3 ................
> 0004a70: 6230 0300 bf03 0000 00cf 0400 0000 df05 b0..............
1622,1623c1622,1623
< 0006550: 0c19 0000 0c06 0e26 003e 001b 000c 0c0a .......&.>......
< 0006560: 0a0a 0100 0000 0200 160a 0500 0405 0407 ................
---
> 0006550: 0c19 0000 1006 0e30 0078 0020 0010 100e .......0.x. ....
> 0006560: 070b 0100 0000 0200 170b 0500 0405 0407 ................
1646,1647c1646,1647
< 00066d0: 0000 0000 0014 730f 0064 3610 0020 8169 ......s..d6.. .i
< 00066e0: 0050 2200 00ac 53ff ff14 730f 0064 3610 .P"...S...s..d6.
---
> 00066d0: 0000 0000 0014 730f 0038 6710 0020 8169 ......s..8g.. .i
> 00066e0: 0050 2200 00ac 53ff ff14 730f 0038 6710 .P"...S...s..8g.
1660c1660
< 00067b0: 1001 0111 750d 714c 0000 c409 0010 0000 ....u.qL........
---
> 00067b0: 1001 0111 840d 824c 0000 c409 0010 0000 .......L........
2008c2008
< 0007d70: 0090 4402 0090 4401 0090 4402 0090 4402 ..D...D...D...D.
---
> 0007d70: 0090 4402 0090 4401 0090 5502 0090 4402 ..D...D...U...D.
3648c3648
< 000e3f0: ffff ffff ffff ffff ffff ffff ffff ff35 ...............5
---
> 000e3f0: ffff ffff ffff ffff ffff ffff ffff ff10 ................
I'm reasonably confident that the 1st, 3rd and last blocks of the diff are not relevant (last is the checksum, the the 1st and 3rd are board IDs).
Since differences between the GTX480/Q6000 and GTX470/Q5000 are negligible, I rather doubt that a Q6000 BIOS will work on a GTX480. I will double-check that when my faux-Q6000 is available for experimentation again.
Regarding the Quadrified/Gridifed GTX680's bizzare problem of refusing to work with DL-DVI outputs (at least in XP64, not tried on Windows 7 yet), I ordered an active DP->DL-DVI adapter. DP works quite differently to DVI, so there is a reasonable chance that this will handle the DL output signal. If it turns out to work, although not a proper solution, at least it will be a very good workaround.
Update: As a random factoid, Fermi Bios Editor doesn't actually understand how to parse a genuine Quadro 5000 BIOS (but parses a standard or modified GTX470/480 BIOS just fine).