I've been having issues with the F20 cards in a Sun T4-1 server, with several incomplete write error messages being displayed. When we attempted to apply the most recent firmware update as recommended by MOS, an error message displayed indicating the .xml file did not have the T4-1 server in it, so the firmware update failed. The initial response from MOS was that it appeared the T4-1 and F20 combination wasn't supported.
I followed up, inquiring if it could be a case where the .xml file was built/published prior to the release of the T4. The response I received was:
“F20 is not supported for T4-1
Engineering states the next generation Flash Accelerator PCIe Card will be supported on T4 series,
available in July”
That being the case, if you're buying a T4 series server and thought that it'd be a real good idea to add the F20 cards for increased performance (probably one of the reasons for buying the T4 in the first place), although they will install and you can use them, you will not be able to upgrade the firmware should there be an issue, and you'll have an unsupported configuration F20/T4.