Why would FW800 connection speed be the same as USB?

[md63]

Since I had a number of spare Sata laptop drives sitting around I decided to purchase an external enclosure to make use of them. After testing 3 enclosures with USB, FW400, FW800 and eSata on my MBP and 2009 Mini, I'm not seeing any increase in data throughput between Firewire vs. USB. The drive I'm using in the enclosure is a 120gb 5,400 rpm Hitachi drive that was OEM in from my 2009 Mini. I replaced that drive with a 500gb 5,400 Hitachi in the Mini and my SR MBP has a 320gb Scorpio Black Drive. Both of these drives should be faster than the drive than I'm testing.

First I bought an Eagle USB/esata enclosure (EAGLE ET-CS2XMESU2-BK). This is a nice enclosure with a very simple eject system. I was using the BC338 card and was getting many kernel panics so I knew eSata wasn't a long term solution. I was able to run a few tests and the eSata connection appeared to be about 50% faster than USB in transferring data.

Next I tried the Macally PHR-250cc which has many fine reviews. Several tests were showing the USB to be as fast or slightly faster than the FW400 connection to my MBP. I transfer both a 6gb folder as well as a 2gb xvid file. This was counter to everything that I had read about the superiority of FW vs. USB. Since the Macally was only FW400 I decided to get a FW800 enclosure since that would surely be faster.

I purchased a Mapower MAP-KC21 FW800/USB enclosure. After testing the same drive I had the following results on my MBP and Mini for writing a 6gb folder to the external.

MBP

FW800 3:53
USB 3:54

Mac Mini

FW800 3:42
USB 3:44

Can anyone explain why my FW800 connection appears to be no faster than plain old USB? My first guess was that the 120gb drive in the enclosure was the bottleneck, however, when I was using an eSata enclosure I was seeing faster transfer speeds. I don't know enough about the relative speeds of the various components of the system to know what could be causing the throughput to be the same. Based on my testing it seems I could save myself some money and purchase a plain old USB enclosure since I'm not seeing any benefit from FW. Any thoughts would be appreciated.

Thanks.

 

[kraftzwerg]

interesting - maybe the advantage of firewire only comes to play when transferring many small files?

 

[macrumorsMaster]

Not sure why that is happening, maybe need bigger files to see a difference.

Main difference I know btwn FW and USB is FW can SUSTAIN the thoroughput while USB can have spurts. That's why video editors use FW and not USB drives.

 

[savar]

I think you mean USB2, right? Not USB1?

USB2 is actually spec'ed slightly faster than FW400 (in terms of max throughput).

One big difference between the standards is that USB relies on the host CPU do perform a lot of logic, whereas with FW there is a dedicated FW controller onboard which offloads some of that work. The result is that when the CPU is loaded, FW throughput will reduce load on the CPU and hopefully be faster.

As somebody else pointed out, FW should have better sustained throughput, too, whereas USB's speed can be burstable depending on other devices on the USB network.

 

[nufanec]

Probably just that the read/write speed of the hard drive is about USB2 speed. Which is quite possible given that it's a low density 5400RPM drive.

 

[md63]

Thanks for your replies. My confusion has more to do with why FW800 is running no faster than USB while it should run almost 2x speed of USB. The fact that when eSata didn't crash my MBP it seemed to run significantly faster than USB. This makes me think that the drive isn't the limitation. Just to Summarize

Case 1 eSata >> USB (50% faster than USB)
Case 2 FW400 = USB
Case 3 FW800 = USB

 

[Consultant]

Hint: 120gb 5,400 rpm Hitachi drive = slow

Look at barefeats.com and see what tools they use to benchmark

 

[sammich]

I guess no one reads posts correctly anymore...the OP did acknowledge that the old, low density drive could be the slow part BUT that eSATA 'appeared' to produce faster xfer times.

md63, can you post how fast the transfer was happening? (in Activity Monitor, Disk Usage tab at the bottom).

 

[md63]

md63, can you post how fast the transfer was happening? (in Activity Monitor, Disk Usage tab at the bottom).

Thanks for your responses. I did a few more tests and found the following from the activity monitor.

Mapower enclosure with Hitachi 120gb drive.

USB 27 MB/s
FW800 27MB/s

I also have a Lacie d2 drive with FW800 and tested that with the same 6gb folder transfer.

USB 25MB/s
FW800 45MB/s

The Lacie drive exhibits the behavior that I would have expected although I can't explain why the USB transfer is slightly slower than the Mapower enclosure with the inferior drive. I also can't explain why my testing with eSata with this Hitachi drive appeared to show faster transfers than USB and since I no longer have the enclosure I can not retest.

It appears the drive (or the enclosure) is the limiting factor and my guess is its the drive.

What would you recommend for a fast 500+gb drive that would be fast enough so that there would be a benefit to using FW800 over USB?

Thanks for your advice.

 

[HBOC]

isn't it just cheaper to buy an external HDD, rather than having to buy an enclosure and a 3.5mm? I have seen the WD 1TB with firewire 800 at Best Buy for $99, and that is regular price. I have "tried" to price an internal HD with an enclosure, and it seems that buying an external is cheaper...

As far as which HD to get, is it internal or external? I have heard great things about the Seagate 500GB 7200 drive for internal. I have a LaCie D2 Quattra that i bought at Apple, and I am very happy with its' performance. It has every interface except for eSate and USB3. But i see that you have one as well

 

[Eddyisgreat]

FW800 is faster than any single rotating disk is able to achieve.

7200 RPM Drives will likely achieve only the 45 MBps you've described. Actually that seems a bit on the high side but it should be doable with higher platter density.

Anyway to max out the FW800 bus with rotational drives you'll need multiple disk I.E. a raid 1/0 configuration.

If you want to max out every bus (USBI/II/1394A/B) and reach the upper limits of the SATA/eSATA bus you'll need an enclosure with eSATA as well as a premium SSD like the Intel X25-M or any SLC based SSD. You'll probably want to call an ambulance as well cause it'll cost $$$$$$$$$$

 

[ymarker]

FW800 can be saturated (rather easily actually) with a 7200 rpm hdd, esp the newer HDD. See here.

Actually even a newer 3.5" 5400rpm HDD will run slow with the old FW800 link. 800 megabits/s = 100 megabytes/s. As you can see from the chart the above 5400rpm/7200rpm hit that ceiling easily. Moreover, I'm not certain the entire 800Mb/s is available for raw data. The actual b/w seen will be < than 800Mb/s.