Flash 2 - CPU utilisation excessively high on Citrix server

we have an e-learning LMS system that is accessed by means of a link in IE from a windows 2008 published desktop. we initially were using a server with 2 x vCPU ( single core) with 24GB ram, this configuration performed really badly with hisses and pops on the audio and choppy video performance. on investigation we could see that the CPU utilization was consistently in the 95-100% range, We added another 2 x vCPU giving us 4 CPU and this helped considerably with the playback. However the CPU utilization is now about 70% for a single user and when we launch a second session the cpu utilisation jumps right up again and we are back at square 1 with poor playback. It is not an option to keep adding CPU's and we should not have to.

Adobe do not offer phone support on Flash. Very poor support for a product that is required by many websites.

I have so far trialled version 18, 20 and 21 of the active x plugin for IE and they all do the same thing. I have configured the flash controls to use a cache / not to use a cache, I have enabled / disabled Hardware acceleration in the flash video with no effect.

The Citrix side of things is configured  to provide server based flash rendering as the endpoint devices do not support Flash redirection. I have also opened a support case with Citrix who maintain the position that apart from when using Flash the HDX driver used for sound and video is functioning perfectly so it is an Adobe issue.

The documentation on Flash is poor and I am now looking for any hints that might help in terms of registry keys , verified versions etc.

We have never had these issues with previous versions ( 9, 10) but since 11 nothing but issues. I have also looked at the enterprise versions but only see 18 or 21 as downloads.

This is holding up a large deployment and will probably end up costing a fortune to redevelop the content as HTML5 if Adobe can provide no answers.

I have checked the forums ( Citrix and Adobe) exhaustively and there seems to be a known issue with resource consumption by Flash. There does not seem to be any acknowledgement of this by Adobe but then again the last interaction I had with adobe was for  Reader (9.x) not being compatible with roaming profiles which they also did not fess up to as an issue. I usually give Citrix a hard time for not testing their products extensively enough but in fairness they are quick to provide fixes so I am hoping that someone from Adobe can jump in here and confirm:

1) this is a known issue

2) that all products are tested in a terminal services environment

3) that Xenapp 6.5 and Xendesktop 7.x are listed as supported platforms

4) that there is a better support method than forums  for enterprises ( and how to find and access it)

5) considerations have been made for resource utilisation in a multi-user shared environment.

6) which logs and diagnostics are required to progress this issue and then what the procedure will be and how long it should take.

I am willing to work with Adobe remotely if contacted. This is a P1 issue for my organisation.