I'm in the process of installing Server 2012R2 on my T20 and after getting the OS setup on my RocketRaid 2720 (due to the fact the T20 only supports 2 SATA 6gbs devices), I enabled Intel Raid in bios and upon reboot, the Intel Raid bios comes up, I can configure the drives plugged into the onboard SATA ports, however the bios for the 2720 no longer comes up.
In the bios I cannot find any settings for changes to allow an addin card's bios to function. So I popped the 2720 in my supermicro server and enabled the on-board Raid and both raid controller bios come up and allow configuration.
I assume all we need is a bios update, so..... lets go Dell!!
I know this is an old post, but I have a couple of comments:
1. My PowerEdge T20 (per Intel RST) shows that the 3 SSDs I have connected to the first 3 SATA ports are running at 6 Gbps. I was a bit surprised to see this given what's been written and what is specified. Has there been a hardware update? FYI, the 4th port, connected to an older HDD (WD RE4 512 GB) shows 3 Gbps.
2. I have been running a HighPoint 2720SGL controller in a Dell Precision T5500 for about 3 years now. At the time I initially set things up as I recall I had to disable the on-motherboard RAID in order to get the 2720 BIOS extension to be seen. More recently I've see that the ordering of how the BIOS extensions appear to be loaded seems to have changed, though I have not had occasion to try to turn on the Intel RAID again.