Yes I noticed that also. 

"Forgot", that is cute ;), maybe the R12 will have it or you will have to wait for R13...

Well, with my new R11 - i9-10900KF - RTX3090 and 64gb/3400MHz ram. I really don't need it. This machine is a beast ! I only play DCS with a HP G2 VR headset and it's all I need. I don't think it will help any in VR too. Also using this rig with the AW3440DW I'm getting over 160fps on high settings. So, I'm not sweating it. 

Not trying to defend Dell here, but Resizable BAR is still very new and many motherboard and GPU vendors still haven't build BIOS versions to support it. Hopefully Dell releases it soon for both the motherboards and the GPUs (which AFAIK are made by MSI for Dell, so perhaps they can piggyback off the stock MSI VBIOS).

https://www.nvidia.com/en-us/geforce/news/geforce-rtx-30-series-resizable-bar-support/

In both the Aurora R11 BIOS 1.0.5 and the VBIOS updates, I do not see any mention of Resizable BAR under Fixes & Enhancements. If the Alienware platform had added Resizable BAR, they would have mentioned it there.

I also noticed that because I went ahead and updated the new Bios. Question After the restart I went to System Information and it still said Bios 1.3.0  Should it said 1.0.5 ?  

Thanks Chris. 

Boot into the BIOS. The Main screen should tell which BIOS Version is installed.

Thank you !