Intel RAID Questions & Troubleshooting

Hi, I’m currently using Intel RST RAID 0 with 2 hard drives. I have some questions and issues that I’m unable to find elsewhere hence I’m posting this here. Hopefully someone will be able to answer them.

In Intel RST app, I get the option to choose different types of cache:

Screenshot _502__013135.png


-Was previously using “Write Back” with write cache buffer flushing disabled-
So here are my questions:
1. Where is this cache stored and shat handles those cache? The Intel RST driver in Windows or in the BIOS?
A: The RAM.
2. When I disable write cache buffer flushing, does it disable buffer flushing on the RAID cache or the drives’ cache?
3. Is the any way to enable write only cache? (in the help page it say Write Back and Write Through includes read cache).
4. Why does enabling any sort of cache on the RAID array cause in game stutters, or ~100 ms freezes on the entire system when the game tries to load textures? The issue is mostly gone if I set the cache mode to “Off” and is entirely gone if I transfer the game files to my SSD.

Screenshot _127__014249.png


-Copying files from SSD to RAID 0 Volume-
5. Why does using the RAID array (writing at ~300 MB/s) cause one CPU Core to max out its usage (by a process “System”)?
6. Why does both the RAID array and SSD perform below specs when I’m using them simultaneously or when copying files from one to the other?
SSD: 165 MB/s
RAID: 200 MB/s
Both ~1000 ms average response time

Usually:
SSD: 530 MB/s
RAID: 300 MB/s
Under 10 ms response time

Specs:
Intel i7-9700 (8c/8t @ 4.7 Ghz)
Asus H370-F
Samsung 860 Evo SATA SSD (Pass through/non-raid)
RAID 0: 2x Western Digital Blue 7200 RPM 1 TB (CMR)
Both SATA 6 Gbps
64KB Strip size
Intel RST 17.5.0.1017 (Windows)
Intel RST 17.2.0.3790 (BIOS)
Windows 10 Pro 21H1

Edit by Fernando: Inserted pictures resized (can be enlarged by clicking onto them)

@Knight_Raider Welcome to the Win-RAID Forum and thanks for your interesting contribution!

Because I haven’t had an Intel RAID0 array consisting of 2 SATA connected HDDs for many years, I can’t answer your questions off the top of my head, but you may find some information within the start post of >this< aready existing thread.
On the other hand the Intel RAID users may be very grateful for a separate thread, whose start post contains easy to understand answers to your questions. Since I don’t have the required time to do it, what about you?
Regarding the “RAID Caching Policies” you can find >here<, >here<, >here< and >here< interesting sources.

Good luck and enjoy the Forum!
Dieter (alias Fernando)

Thanks for the info. I did check that post out before I posted but unfortunately it doesn’t my questions, hence why I started a new thread (maybe I should have commented there instead?).

I guess most of the cache should function the same with SSDs as well, perhaps you can share some info on that? Do you experience any sort of bottleneck with the driver? Does RAID 0 require that much CPU cycles in most systems?

@Knight_Raider

The choice of the “best” matching Intel RST RAID driver version is very important. According to my own benchmark comparison tests the differences may be really noticeable while working. My tip: Find out the best Intel RST driver for your specific configuration and - if needed - customize the RAID module of your MB’s BIOS.

A RAID0 configuration stresses the CPU. That is why I do not recommend any CPU overclocking.