I dunno, I can't find a GFX string for it, and almost everyone else I've read who're using the GTX 260 are using GraphicsEnabler and it works perfect. That's what I used before on my old motherboard and it said x16. I ran nvclock and it says I'm "Current Rate: 8X, Maximum Rate: 16X". So, I think it's either my card, or it's some issue with the 10.6.4 drivers like some people have mentioned. I tried using LegacyAGPM and set up an iMac11,1 section with the GTX 260 section from the real AGPM's MacPro4,1 section, and it hasn't made a difference. It actually does seem like the card is running in power save mode all the time. If a launch a game, nvclock still says 300Mhz, when I should be at 626 right? At this point though I've just about hijacked this thread so I guess I ought to start a new one.

Edit: I did just try an EFI string instead of GE, and it still says x8. It's gotta be either my card or my motherboard. Obviously x8 is still plenty of bandwidth for the GTX 260, and everything else is fine, but I don't like that it's not working the way it's supposed to.

Slayer how is your new card? I was thinking of going the ati route, still on the fence

Power save mode actually does make sense. I did have this problem initially (lower clock but still x16 PCIe) and started to look dipper into it. But then when made all the necessary changes to my dsdt it magically disappeared so I did not look any farther. Here is my NVClock info if u'd like it for reference.
-- General info --
Card: GT200 [GeForce GTX 260]
Architecture: GT200 B1
PCI id: 0x05e2
Subvendor id: 0x19f1
GPU clock: 586.284 MHz
Bustype: PCI-Express

-- Shader info --
Clock: 1296.000 MHz
Stream units: 216 (11111110b)
ROP units: 28 (01111111b)
-- Memory info --
Amount: 896 MB
Type: 448 bit DDR3
Clock: 999.000 MHz

-- PCI-Express info --
Current Rate: 16X
Maximum rate: 16X

-- Sensor info --
Sensor: Analog Devices ADT7473
Board temperature: 37C
GPU temperature: 47C
Fanspeed: 339 RPM
Fanspeed mode: manual
PWM duty cycle: 40.0%

-- VideoBios information --
Version: 62.00.50.00.05
Signon message: NVIDIA GTX260 896MB
Performance level 0: gpu 300MHz/shader 600MHz/memory 100MHz/1.05V/100%
Performance level 1: gpu 400MHz/shader 800MHz/memory 300MHz/1.05V/100%
Performance level 2: gpu 590MHz/shader 1296MHz/memory 999MHz/1.12V/100%
VID mask: f
Voltage level 0: 1.05V, VID: b
Voltage level 1: 1.06V, VID: a
Voltage level 2: 1.12V, VID: 5
Voltage level 3: 1.18V, VID: 0

And you are right this does not have anything to do with this thread and there is already plenty of info on this subject.

Yeah looks just like my output but I have the 216 superclocked so some clocks are higher in mode 1 and 2, and it's definitely stuck on mode 0. I ran some stress tests and it didn't budge past 300Mhz. Is your DSDT just like the one on page 24 or does it have other stuff?

The dsdt file I posted on page 24 is still the latest and the one I am running right now.
PS FYI It is not just dsdt. It is a combination of dsdt and ssdt. There are tables/references in both and in some cases ssdt takes a priority. But most of the changes I've made are in the dsdt.

Interesting. I added the SSDT files (I don't fully understand the concept behind them, I guess just more of the same as DSDT) and put in dropssdt=yes, and now my gpu clock is at level 2 (626Mhz for me since I have the 260 superclocked :)), but, unfortunately I'm still at x8 lanes. Actually now it even clocked down to level 1 at 400Mhz, so that's good too, but STILL x8 lanes. I've got another week to return the board if I need to, and I just remembered my zotac ion has an x16 2.0 slot so I could test the card on that if I feel like tearing that machine apart to fit it on there.

The card works smoothly so far. the most important feature that i really needed is not supported which is CUDA. i was hoping CUDA worked, but im on a waiting game right now for new drivers from nvidia to leak out.

Gaming is pretty smooth so far. I just play starcraft 2 (Ultrasettings).
I just dual boot with windows 7 for video editing.

so far from reading the article in insanelymac, these are the problems: vsync problems, no cuda, openCL.

If ati cards are fully supported with no problems at all, i suggest getting an ati card for a smoother experience. My system is not really vanilla right now because of the drivers you have to install for the GTX480/GTX470.

Glad dsdt/ssdt files worked for you and you are getting full performance out of your video card.

Good info thanks, think its time for me to do a re-load with all of these new fixes implemented. Still running with strings on my 285 only game i play is call of duty so my system is overkill. I'll probably grab a 5870 when the funds line up

CD Drive Issue
 

I first want to thank you all for the wonderful information. This is truly exciting stuff.

I followed this guide, finally got sound working, but have 1 more thing that I need to fix.

I am unable to use my sata cdrom, it doesnt show up anywhere. Not sure where to start here so I'll just list my stuff

EVGA X58
i7 920
6 gigs ocz ram
nvidia gtx 280
samsung sata dvd-rw

I'm pretty sure that I have a custom dsdt.aml file, however I am not too sure.

Any suggestions? Thanks in advanced.