Sata vs Gigabit Speeds - Video Editing

n64man120

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I've got an older Mac Pro that I use for video editing with 2x500GB Sata drives in it. I would like to get a second Mac Pro, and be able to share the content between the two of them, so either machine can be edited on, or both at the same time on different projects.

I'm looking for advice on the best way to go about this, without getting painfully expensive. If I get a gigabit NAS enclosure and drop a terabyte or two into it, how will my transfer speeds hold up compared to the sata link I currently have? Any better ideas for having a central content server between the two machines?

Thanks
 
Gigabit ethernet is slower than either SATA1 or SATA2. But still faster than a harddrive can keep up with.. You'll likely lose some burst speed capability, gain some access latency, but doing video encoding, I don't imagine it would limit you significantly if at all doing video encoding though. Once a stream starts it's probably more about the average transfer rate than burst or random access.

But why not just have the harddrives in one computer, and network share them with the other. Would remove the external enclosure cost.
 
The speeds will be similar, depending on the hard drives you have and the setup.

Expect average transfer speeds of 40-60MB over GigE. SATA transfers can go anywhere from 40-75, but probably around 50-60 for the most part.

Direct SATA in the machine will probably be faster, but you might not be losing much. You could just share the drives from the system, that way you don't have to buy a NAS.
 
Good call on the network share, as always the most obvious solution is overlooked!
 
On my recent Nas box purchase, I found this site Small Net Builder to offer the best reviews and advice for the home networker.

For some easy comparison shopping, he has a great Charts section here. SNB NAS Charts

This is kind of interesting from there.
NOTE: As a reference, the maximum raw data rate for 100Mbps Ethernet is 12.5 MBytes/sec and 125 MBytes/sec for gigabit Ethernet. Throughput above these values is generally due to OS caching.

But most of the Nas boxes that they have reviewed transfer data under 30 MB/sec. Much slower than SATA, but probably fast enough for your needs.

I went with a 1 TB Hammer Myshare that I have running in Raid 1. The only problem I have had with it in 3 months was it dropped offline last week while I was out of town and I had to talk my wife through power cycling it over the phone. I am very happy with it otherwise.:)

Don
 
If both your Mac Pro's have the dual GigE connections you could even go with a direct connect between them.

Hrm, I believe they do. On that thought, what about firewire 800. I don't have much experience with it, but can't it network two hosts in similar fashion?
 
Hrm, I believe they do. On that thought, what about firewire 800. I don't have much experience with it, but can't it network two hosts in similar fashion?
gigabit = gigabit
firewire 800 = 800 megabit

But that's fine, as mentioned, harddrives have avg transfer speeds of around 40-70 MB/s depending on the drive. 800mbps is still 100MB/s. Eeven account for some overhead loss, should still be able to get most drive performance.
 
Well, gigabit and firewire speeds between pc's don't always max out. It all depends on the bus of these network cards. I don't know much about Mac's, but if they're on standard PCI bus you will have a speed limit at around 20MB/s regardless of the theoretical speeds.

You need a higher bandwidth bus like PCI Express in order to achieve higher speeds.

I tested with both Gigabit and Firewire 400 between two pc's (one with PCI based cards, one with PCI Express cards) and in both cases the speed maxed out at 20-22MB/s.
 
Well, gigabit and firewire speeds between pc's don't always max out. It all depends on the bus of these network cards. I don't know much about Mac's, but if they're on standard PCI bus you will have a speed limit at around 20MB/s regardless of the theoretical speeds.

You need a higher bandwidth bus like PCI Express in order to achieve higher speeds.

I tested with both Gigabit and Firewire 400 between two pc's (one with PCI based cards, one with PCI Express cards) and in both cases the speed maxed out at 20-22MB/s.
On intel based systems, the gigabit has it's own direct path to northbridge... not southbridge PCI/PCIe bus.

Using both mine and my dad's onboard NICS, can sustain 50MB/s through his switch doing ISO's no sweat.
 
That depends on the MB manufacturer, some choose not to use that feature.
I have an older 865PE MB (Asus P4P800 Deluxe) and it has a 3COM Gigabit controller on the PCI bus.

On intel based systems, the gigabit has it's own direct path to northbridge... not southbridge PCI/PCIe bus.

Using both mine and my dad's onboard NICS, can sustain 50MB/s through his switch doing ISO's no sweat.
 
I don't know much about Mac's, but if they're on standard PCI bus you will have a speed limit at around 20MB/s regardless of the theoretical speeds.

You need a higher bandwidth bus like PCI Express in order to achieve higher speeds.

Not true. 32 bit PCI supports up to 133 MB/s. It doesn't have any problems supplying SCSI cards with 60MB/s.

Regardless Mac Pros use PCIe exclusively.
 
Not true. 32 bit PCI supports up to 133 MB/s. It doesn't have any problems supplying SCSI cards with 60MB/s.

Regardless Mac Pros use PCIe exclusively.

Yes, in theory 32-bit PCI bus has up to 133MB/s but that is shared bandwidth and there are various factors contributing to the bottleneck (protocol overhead, other devices like your SCSI card). There are numerous reviews and tests all over the internet besides my real life tests confirming this.
 
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