DVI > VGA Adapter // Performance Problems

On OSX 10.6.3 // AMD Based System:

I am using a DVI > VGA Dongle on my AMD System since a few months now, and always wondered why my ATI Radeon HD 4850 is performing so bad.

On Benchmarks it gives about 25-50% of the performance it should.

At first i thought it was some Problem because i just got the Radeon to run with EVOenabler.kext but yesterday i build an Intel Hackintosh with a GeForce GTX285 and had the same Problem. The GTX285 is enabled via EFI-String and fully working.

When i don't connect the DVI > VGA Dongle and the Card is connected directly to DVI it gives me full performance.

So, the Questions I have are:

- Anyone else experiencing the same issues?

- Is there some fix/workaround for this? (to get full performance with DVI>VGA Dongle)

Since my HD 4850 doesn't work at the moment without the Dongle, and i got no Display with DVI at my other home, simply connecting it via DVI wont work for me at the moment.

EDIT:

SOLVED >>

I disabled /System/Library/Extensions/AppleGraphicsPowerManagement.kext
Now everything works perfectly fast with my NVidia Cards.

I will give it a try on my Radeon 4850 System in a week or two and keep you updated.