2x NVMe M.2 SSD Raid0 (PCIe Gen.3 x4 + PCIe Gen.3 x2) question

insolito

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Hello, I just bought a AMD x470 motherboard (ROG STRIX X470-F GAMING) and I'm thinking of doing a raid0 of 2x NVMe M.2 SSD.

But from what I understood from the manual, i have two m.2 slots, one at PCIe Gen.3 x4 speed and another at PCIe Gen.3 x2 speed.

So, i have two doubts, (considering 2x equal PCIe Gen.3 NVMe SSD to mount a raid0):

#1: If i do a raid0 with these two SSD, they both will run at PCIe x2 speed?
#2: Even if it runs at "x4 + x2" or "x2 + x2", i will have a big performance loss compared to a raid0 "x4+x4"?

Thanks in advance!
 

bmockeg

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There is absolutely zero reason to attempt a RAID with m.2 devices. It will hinder performance rather than help. To answer your question, yes one drive will run slower, should have gotten a board with 2 x4 slots.
 

insolito

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I will use it for games, and coding. So, i was expecting for better loadings
 

insolito

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Even for better loadings? I know, Almost always one bigger drive is better than two smaller drives, but i cant afford for the bigger one right now, my plan was buy just one right now, and another from 2018 BF to make the raid0.
 
RAIDing SSDs looks good in synthetic benchmarks for sequential read/write (often with high queue depth). You're never going to see those values in real life. A lot of regular consumer use is random I/O at low queue depth, which can actually be reduced with the SSDs in RAID0. So basically you're unlikely to see any performance improvement, possibly a tiny performance penalty, and you've now doubled the chance of losing all the data in the volume (if either of the SSDs fails).

I wouldn't recommend it.
 

bmockeg

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IF, big IF, you get RAID working with 2 m.2 drives(good luck!), you will likely have DECREASED performance rather than increased. You won't find anyone on this forum that knows what they are talking about that will recommend doing a RAID for m.2 drives.
 

insolito

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Even if i dont mind about lose my data? (i can always download my games again, and i git my code, so, no data lost)

Last question:

Internet says: PCI Express 3.0's 8 GT/s bit rate effectively delivers 985 MB/s per lane, so maximum 1970MB/S at PCIe 3.0 x2 speed or maximum 3940MB/s (2x raid0) at PCIe 3.0 x2 speed , right?

I was aiming for 2x Corsair MP500 120GB, apparently they achieve 3000MB/s read and 2400MB/s write at max sequential read/write

This combined with my impossibility of buy a single 240GB SSD right now, maybe it is better to buy one now, and another on the BF to do this raid? Even at x2+x2, this raid technically is better than a single one drive, 3940MB/s vs ~3000MB/s
 

bmockeg

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My opinion is wait till black Friday and buy ONE drive and be done. You apparently aren't understanding. Chances are you won't even get RAID to work in the first place. If You do, IT WILL BE SLOWER THAN USING A SINGLE DRIVE. There is NO BENEFIT
 

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