Need some help about UEFI Trim Raid

I have 5 questions about the Win 8.1 64 bits UEFI installation on Rampage IV Black edition - Intel Core i7-4960X - 2 x Raid 0 Samsung SSD 840 PRO 256 Go - SLI 2x ASUS GTX770-DC2OC-2GD5. I didn’t yet buy the computer and I’d like to have some answers before to not spend money.
I understand that I have to install the OS in UEFI Mode to have Trim enabled with Raid 0 on the Mobo Rampage IV Black edition and that I have to use the Intel RST v.
I read a Win 8.1 UEFI installation guide for Raid users which explains that I have to set Secure Boot on “other OS” and CSM as disabled.

1- But I read some issues with CSM disabled and SLI 2x ASUS GTX770 or other GTX 7… Impossible to set CSM disabled with SLI enabled. The ASUS GTX770 bios is UEFI GOP (unless I do a mistake), so I don’t understand why it is impossible to set CSM disabled when SLI is enabled? Do you know this issue? I try to understand before buying my computer. If the CSM is enabled (because of issue with SLI), will the UEFI installation OK to have trim on Raid 0?
I’d like to know if CSM enabled is not a problem for trim raid 0 on my Mobo and if the UEFI installation would be good even if CSM is enabled.
Perhaps someone can tell me that SLI 2x ASUS GTX770 enabled is compatible with CSM disabled?

2- I ‘d like to know also if Blue-ray LG BH16NS40 shows UEFI prefix to install Win 8.1 from the DVD? If not, could you give me advices about some models which allow the UEFI prefix to install Win 8.1 from the DVD?

3- I read that some people could not use the Intel RST drivers with Samsung SSD 840 Pro but I’m in doubt. Could you confirm me that there’ s no issue to install Intel RST drivers on Raid 0 2x Samsung SSD 840 Pro?

4- To install the Intel RST drivers for Raid 0, what’s the best choice: F6 drivers or Intel software in OS?

5- I read the Fernando post about “Detection of SSDs by Win8/8.1 and the use of the Optimizer”: Both Windows 8.1 versions (Preview and
RTM) have a severe bug: The OS doesn’t detect RAIDed SSDs and sees them as HDDs. Then there was a workaround to solve the problem. Is it yet a problem with actual Win 8.1 or is it solved now?

I thank you all in advance for the help.


You should install Win8.1 by booting off an USB flash drive formatted with FAT32 (the installation is much faster and you save the money for a DVD). The best tool to get a bootable Win8.1 image for an UEFI mode installation is Rufus.

I never had a problem to install any v12 Intel RST driver for my 2x256 GB Samsung 840 PRO RAID0 system.

Usually loading of an F6 driver is not needed, because Win8.1 has Intel RAID drivers v12 on-board. Once the OS is up, you can install the Intel RST Driver & Software Set you like.

This problem has been solved by Microsoft latest with the Spring Update. Nevertheless you should check, if your SSDs are detected as SSDs, before you are going to run the "Optimizer".

I thank you very much for your quick help!