405 MB/s Transfer Rate!

[wheezy]

So just for fun I decided to make 2 RAMDISKS on my MacPro and see how fast I could move a file between them. Picked a HB'd movie of Seabiscuit (1.16GB) and moved it over from my Hard Drive to ramdisk1, took 5 seconds, squeezed out just shy of 200MB/s with my RAID0 (2 Samsung F1).

Using the new screen record of Quicktime X I decided to record just how fast I could move the file from ramdisk 1 to ramdisk 2... 405MB/s, took 2.5 seconds to move the file.

YouTube HD

Even though it's HD, it's still hard to see since my original is a 1680x1050 Screen Capture. If you'd like to download the original QT file, Click Here.

So, what does all this mean? Well, seeing as a RAMDISK will be erased the second the power goes off on the machine or you eject the drive, it doesn't mean a whooole lot. It was just a lot of fun. Other than setting them up for a scratch disk for PS, I don't know what you could really do that would make a effective use of that speed.

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If you'd like to give this a whirl yourself, just enter this code into Terminal:

diskutil erasevolume HFS+ "ramdisk" `hdiutil attach -nomount ram://1165430`

1165430 = 550MB
2330860 = 1.18GB

To make a few of them, just give each one a different name.

 

[Infrared]

Using the new screen record of Quicktime X I decided to record just how fast I could move the file from ramdisk 1 to ramdisk 2... 405MB/s, took 2.5 seconds to move the file.

I'm surprised it's not faster. These guys get 2GB/s from an SSD RAID:

http://www.youtube.com/watch?v=YmjJqJV1Wsk

Surely memory transfers would be faster than that?

 

[alphaod]

Sorry to say this, but it looks like you need faster RAM

 

[wheezy]

Sorry to say this, but it looks like you need faster RAM

That's a yummy number, were you moving a file or does it just test it's own info?

I can't really put in any faster RAM seeing as well... it's the spec it was made for.

 

[wheezy]

Well, I just found that AJA App and hit 1843.5 / 931.6, but the numbers are all over the place.

 

[wheezy]

I'm surprised it's not faster. These guys get 2GB/s from an SSD RAID:

http://www.youtube.com/watch?v=YmjJqJV1Wsk

Surely memory transfers would be faster than that?

I think if it were possible to span out the image over all the ram instead of 1 stick it would increase quite a lot. They're getting that cause of how many drives their using. If I were to make a 4GB image maybe it would speed up, I'm not sure how it writes the info - if it would do it like a RAID or not and spread the data out.

 

[Tesselator]

Data in memory IS interleaved. In dual channel mode across 2. In triple channel mode across 3 and in quad-channel mode across 4 but that's not available on Mac Pro's for now.

 

[Tesselator]

Sorry to say this, but it looks like you need faster RAM

Sorry to say this, but it looks like you need faster RAM

 

[nanofrog]

Data in memory IS interleaved. In dual channel mode across 2. In triple channel mode across 3 and in quad-channel mode across 4 but that's not available on Mac Pro's for now.

That blows. What gives?

BTW, on the bench data.... You're evil!! Makes my measly 1.39GB/s (mechanical disk) appear to drag @ss.