Hi,
 
i used the OC Guide with my SLI Board and it runs fine at 4,3 Ghz (3820 CPU).
 
As recommended i disabled these features:

• C1E, C3, C6 and C7 set to Disable - These are powersaving features.

• EIST set to Disable. This is Intel Speedstep Technology.

• DO NOT DISABLE TURBO MODE! This essentially allows your CPU to OC at all!

What should i do or enable again to get lower Core Speed when the PC is in idle Mode. At the moment it runs permanently at 4,3 Ghz and i set the Turbo Mode manually to a x12 multiplier with the E-Leet Tool if i am just surfing etc.
 
Thx for help !

At 4.3 you could use a bclock of 100 at multi of 43 - so you might be able to leave those settings enabled.  That said there are some reports of instability with the C-States enabled - some random freezing issues.  I'd leave them off until EVGA has a chance to look at it.  (You could give it a shot and see what happens.)
 
I believe those states are rendered useless with a bclock of 125 - so anything past 4.3 GHZ they are shut off automatically.

Make sure in Power Options (Windows 7) that the OS is covering for the loss of C-states power saving features.

Power Options -> Change Plan Settings -> Change Advanced Power Settings -> Processor Power Management -> Minimum Processor State = 30%

This will let the processor run at a 12 multiplier with low voltage through software instead of on a hardware level that the C-states would have offered.