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Deadmeat553

RAID my RAM?

5 posts in this topic

I've been thinking a lot about RAID 0 lately, and it occured to me that in a system with at least two sticks of RAM that it might be possible to RAID 0 those sticks while in use as a RAM Disk (For those who don't know, that's what DimmDrive is). Basically my idea is as such:

 

System contains 2x8GB DDR3 1600MHz

Typically DimmDrive will use 16GB of storage at 1600MHz

With RAID 0, DimmDrive will use 2x8GB at 1600MHz

 

While this may not sound faster, the difference is that the data is being split between each stick of RAM instead of being shared by them, so you would have a Y: Drive and a Z: Drive while using DimmDrive with Raid 0. This means that the actual speed is 1600MHz, but because you are processing the data 2x faster because you are dividing it among two different drives, it is more like 3200MHz.

 

Sorry if DimmDrive is already creating some sort of micro-drive internal to the drive it creates and is already doing this.

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Hey there,

 

I was thinking about this and I think the limitation is more so with the RAM bus bandwidth than each individual chip.  The reason is this bus speed has a fixed rate and not a cumulative rate.  Meaning, 16x pieces of RAM "raided" together in 1GB chunks is not 16x the speed of 1x 16GB chunk.  Each chip does NOT have it's own bus to the CPU.  It all shares the same bus path to the CPU.

 

So no, I don't think it would be an increase at all.  I believe it would be a decrease in speed simply due to the parity split calculation required for double read/double write between the 2 for the RAID0.  While a super fast CPU would help with this, we are talking extremely fast and extremely large numbers for a ramdisk, and even a mega ultra yellow megaman CPU would be bogged by this.  

 

Interesting question though!  I allowed multiple ramdisks with an older version of Dimmdrive (though this had issues with real-time file syncing).  I might try this out on my mega 64GB overclocked beast just for giggles.

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My MSI mobo can detect each stick of RAM individually, despite behind wired together like you said. With that, I don't see why it shouldn't be possible to make each stick into seperate drives and then RAID 0 them for improved speed.

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Yup, regardless of how each stick is detected, it still goes off of your RAM bus to the CPU.  So everything mentioned above really does ring true. 

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