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v-i-c-

macrumors member
Original poster
Sep 18, 2004
79
3
I hope this posting and the movie will help some people who (like me) always wondered how an SSD might perform on FireWire 400. (I don't want to open the iMac if it is not really necessary)

Getting better access and seek times is the goal. The throughput of ATA/66 or ATA/100 isn't much faster anyway so FireWire might be a valid option to get at least one of the benefits of an SSD.

I've made this test on a Mac Mini 2011 to get pure FireWire performance without possible limitations of the FireWire controller in some older Macs (if there are any). The system on the external SSD is identical to the system on my internal SSD so you can get a rough idea how much of the performance is lost. The drive is the cheapest 128GB SSD that I could get (an Intenso 3812430 SSD for just 50,– EUR) - the FW case is from a Lacie D2 Quadra.

Keep in mind that this is Yosemite, Leopard is much more lightweight and should boot much faster.

I'll post another video how it performs as the external drive via FW400 on an iMac G4 800 once it arrived there (the drive is currently on its way to my mother in another city.


XBench FireWire 800 results:

SSD_FW_800_results.png


I forgot to measure the drive with FW400 before I shipped it :-/ I'll post another screenshot comparing the performance of the SSD @FW400 ves internal iMac drive in some days.
 
ATA/66 is about twice as fast as FireWire 400 at maximum throughput of 66 MB/sec compared to FireWire 400's 400 MB/sec. There are no performance gains to using a FireWire bus over the ATA bus in a Mac. In the Macs that have FireWire 800, they have an ATA/100 bus. In the Macs that have an ATA/33 bus, the FireWire 400 is limited by the internal shared PCI bus to be about 33 MB/sec.
 
Yes but it's not about a gain in performance over ATA. It's about using a SSD without the need to open the Mac first. (I doubt that my mum can install a SSD in her iMac G4. She is 71. – And other people just might not want to open their machines)

The original drive is slow, I hope the slower firewire bus shouldn't be a bottleneck compared to the speed of the original drive. So you should get same throughput performance but faster access and seek times on top. But I hopefully can benchmark it in some hours when the drive arrives there (remote desktop).

ATA/66 is about twice as fast as FireWire 400 at maximum throughput of 66 MB/sec compared to FireWire 400's 400 MB/sec.

400 MBit/s = 50 MB/s, the throughput of FW400 is 75% of ATA/66
 
Benchmarks are as expected. :) Sometimes a bit slower but random access is faster (sometimes dramatically).

Original iMac G4 drive (ATA/66) which is a 60GB Seagate Barracuda ST360015A:

iMac_original_HD.png


Intenso 128GB SSD (3812430 SSD) on iMac G4 via FireWire 400:

iMac_G4_FW400_SSD.png


Overall: 2.32x faster
Sequential uncached Write (4k): 1.27x faster

Sequential uncached Write (256k): 1.07x slower
Sequential uncached Read (4k): 1.58x slower
Sequential uncached Read (256k): 1.03x slower

Random uncached Write (4k): 11.65x faster
Random uncached Write (256k): 1.88x faster
Random uncached Read (4k): 13.01x faster
Random uncached Read (256k): 1.82x faster
 
400 MBit/s = 50 MB/s, the throughput of FW400 is 75% of ATA/66

Minor typo in my first post. It should have read "...compared to FireWire 400's ~40MB/sec." Still, I've never had a FireWire 400 drive go faster than 38 MB/sec whereas I've had an ATA/66 device reach and hold 64 MB/sec for extended writes.
 
Still, I've never had a FireWire 400 drive go faster than 38 MB/sec whereas I've had an ATA/66 device reach and hold 64 MB/sec for extended writes.

But that's still a difference of 1.68x and not 2x. ;-)
As you can see on the screenshots the FW400 in the iMac (or in the Lacie case) can't handle the full speed of 400 MBit/s (50MB/s). But anyway that is not the point of this thread.

The point of the thread is: I don't want to open the iMac. Does it make sense to try to run my system from a FW400 SSD attached to my vintage iMac or will I end with a performance worse compared to the original internal drive?

Everybody knows that FW400 is slower than ATA/66 and 15x slower that SATA III. But how does that affect the improved access and seek times? Is it still worth to do it because you will get faster seek times? I would clearly say yes. Here is the video with the drive finally attached to the iMac:

 
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