sampledi

I feel like it is 2007/2008 again .... I'm struggling with this almost whole week:
Supermicro X8DAE
Xeon 5530 x 2
Nvidia GTX 570
24GB RAM
SSD for OS

- Installation went smoothly, like many times before with different configurations (however this is my first dual Xeon build)
- After restart I see that I can barely interact with UI. Terrible lag and completely unresponsive. Ok .... looks like GPU issue, although that is very strange because the same GPU works W/O issues on X58A-UD3R and Z77X-UP5TH (GraphicsEnabler=yes).
- Safe mode (-x), boots fine, both CPUs are there, RAM ..... good.
- For troubleshooting I deleted GeForce.kext, reboot. System boots fine (of course with crippled graphics), but there is no lag and freezing. Definitely looks like GPU issue.
- Edited AGPM.kext (device ID and threshold), than fakesmc.kext to match Mac Pro 5.1 system definition. Installed GeForce.kext back, reboot. Result - just a bit less lag and freezing, but far, far from normal.
- Again safe boot, system boots fine, no lag.
- OK, maybe I'm going mad .... pulled out GTX 570, installed GTX 285 (also from other working system), edited AGPM.kext accordingly. Result - same lag and freezing.
- Back in with GTX 570. I installed Windows (just to check that there are no hardware issues with MB). Everything works great.
- Formated drive (to avoid temptation of the dark side )
- Reinstalled OS X with Mac Pro 3.1 definition this time (to avoid AGPM). Result - even more freezing.
- Back to Mac Pro 5.1, GraphicsEnabler=no, GPU injection via DSDT .... no luck.
- Various tests with different BIOS options,.... nothing

What ever I try, with any GPU, I always have lag and freezing. Safe boot and booting without GeForce.kext are fine. I have read countless threads trying to find solution, but W/O success.

I'm probably overlooking something obvious .... but WHAT?
Any help would be much appreciated.

Kext used:
fakesmc
hnak's e1000 (for intel network adapters)

DSDT attached

After many successful Gigabyte and Assus based builds,  I decided to go with dual Xeon hack:
2x Xeon E5530
Supermicro X8DAE
Nvidia GTX 570 (GraphicsEnabler=Yes)
24GB Ram
SSD for OS and couple other drives

Installation went smoothly (as many times before with my other hacks). However, after reboot, as soon as I get to country selection, system slows down to a crawl, with spinning beach ball appearing every couple of seconds. For example if I click on "show all countries" it will take about minute or more to show the list.
If I boot with -x (safe boot), I can finish the installation, create account and everything works as it should. Without safe boot, I get to the login screen, and again same story ..... dead slow, beach-ball.
This shouldn't be GPU issue because same card is working with graphic enabler on two other builds.

I'm using only fakesmc and kext for Intel network adapters.

If somebody that have Supermicro X8DAE working with Mountain Lion, can post the following files, that would be great! : DSDT,
org.chameleon.Boot.plist,
SMBios.plist
and kext used

Situation:
Intel CT Desktop Adapter EXPI9301CT (82574L) installed on multiple hacks (Z77X-UP5TH, X58A_UD3R, AsusP5Q). Adapters are working fine either with Hnak AppleIntelE1000e or edited Intel82574L kext. They are on separate network, W/O internet access, connected to NAS, delivering 110 Mb/s write & 111 Mb/s read ..... and that's great.
However, from specific reason, I would like to have jumbo frames enabled:
- MTU set to 9000, after 30 seconds connection drops off. In system preferences it says that adapter is connected and working, but it is not and I can not access any shares.
- MTU set to 4000. Connection stays on, according to Blackmagic Disk Speed Test I have 115 Mb/s write but 0 read.
In order to rule out errors in other network equipement I have tried:
- Connecting through managed switch to 4 port link aggregated NAS (4 port Intel server adapter on Debian Linux)
- Connecting directly to one port on NAS
- Connecting two hacks with Intel CT Desktop Adapter directly

Results are always the same as described above, so conclusion is that error is somewhere in OSX driver or some specific settings. According to older threads it looks like that some users actually have jumbo frames enabled, without any issues?
Any help would be greatly appreciated!