Windows Media Video (.wmv) rendering times have slowed down on Vegas Pro 11

Hi everyone.
I have been coming to this forum for about 3 years now, but only recently have I started to post. I admit that I am a Vegas Fan Boy. Anyway, I have some observations about Vegas Pro 11:
I render a lot of video to Windows Media Video .wmv
So I was eager to see if Vegas Pro 11 64 bit(using latest build update 425) could render this any faster. I was quite shocked at the results so I did some proper testing to give you some real world results.
I used a 8:30 minute 1080-25p Project with a full range of video, titles & effects included as my test subject.

*Test One - Vegas Pro 11 with GPU turned ON in Video-Preferences.
At 5:00 minute mark, 20% rendered with 19:00 min to go - Total render time took 22:38 min.
During this time my CPU was doing "yo-yo" exercises - pulsing from 50 to 75% usage - never went 100%. The GPU was doing a similar thing.

*Test Two - Vegas Pro 11 with GPU turned OFF in Video-Preferences.
At 5:00 minute mark, 30% rendered with 11:33 min to go - Total render time took 14:04 min.
During this time my CPU was utilising about 90-95% of capacity.

*Test Three - Vegas Pro 10
At 5:00 minute mark, 32% rendered with 10:15 min to go - Total render time took 12:59 min.
Using Vegas Pro 10, near 100% of my CPU is being utilized - no pulsing at all - always been very happy with this performance.

I have reported this to Sony Creative Software.
I have a fast, clean and totally new Computer System with no crapware installed. Until this is sorted out, I will be sticking to Vegas Pro 10 for any WMV rendering.

Has anybody else used WMV to render with yet on Vegas Pro 11?
It appears that there are some (dare I say it) big problems with the GPU assist re-inventing the rendering wheel for some codecs. I have faith at this stage that the software engineers will work this out.

My PC Specs:
CPU: Intel i7-2600k @ 4.6 GHz
GPU: Nvidia GTX460
RAM: 16GB Corsair Vengeance
Boot Drive: 120GB Solid State Drive
Storage: 2 x 1TB Hard Disc Drive
Sound Card: Creative Soundblaster X-Fi Titanium