hard drive benchmarks vs real time transfers question

my usb 3 external is showing around average 100 mb/s transfer read rates on benchmarks through HD tune and crystaldisk mark tests. But in reality when i transfer a file either large or small i get around 50 mb/s sometimes slower! the drive in my computer is 5400 rpm while the drive in the external is 7200 rpm.

I am aware of bottleneck issues, but surely a 7200 rpm sata II external connected through usb 3 to an internal 5400 HDD should yield speeds of at LEAST 60mb/sec (double that of usb 2).

(I would like to point out to those familiar with crystal diskmark software, that when testing the 512K test, i generally get the speeds i would be getting in real time transfers, but under sequential test, the speeds are 100+ mb/sec, what does 512k mean anyway?)

Why are my benchmarks good but my real life transfers suck so bad? anybody?

 

If you had a non-system (O/S) partition to copy from, it would make a difference.

With GB-Lan, I can achieve 80-90MB/s sustained transfers between two notebook systems. Copying the same files from the O/S (C drive, the transfers do slow down to almost your speeds (I have 7200 RPM drives).

Real world 'tests' always trump benchmarks - while benchmarks can indicate what is better, it's predictions don't always turn out accurate.

You may also want to try disabling any A/V software (the only real test though is to completely un-install it...) to get your actual throughput more closely aligned with the benchmarks.

Keep in mind that it also depends on the type of file(s) you're transferring and the size of those files too. One big file (2GB) will take less time to transfer than the same (total, 2GB) size of 10,000 little files.

Is your HDD defragged? (I recommend PD11 Pro for this task).

Are you running the latest AHCI driver for your system?

Finally, you can't simply state an arbitrary '... speeds of at LEAST 60mb/sec...' 'score' you want to achieve.

You must temper that with the real speeds your slowest HDD (the 5400 RPM one) can achieve on the inner (slowest) part of the platters.

Hope I have given you something to think about (and optimize/fix too).

Good luck.

 

wow thanks for the elaborate answer that was good. While i understand what youre saying, my laptop is relatively new, meaning that the hard drive and the included usb 3 port should be yielding speeds close to what other people online have demonstrated. If i am transfering files to my hard drive at 40-50 mb/sec average, with a 7200 rpm external drive at usb 3.0, most people would agree that its a little on the slow side. (some saying the really slow side)

Im inclined to believe that its my external case that sucks, and because i did have the pleasure to try out a different usb 3 drive about a month before i purchased my external usb 3 drive, I can safely say the speeds between the two are dramatically different. while i faintly remember my exact speeds for the first USB 3 drive I remember it being alot faster and 'impressive' if you will.

the hdd is not defragged but doesnt need to be because it was formatted yesterday and is brand new, i checked my drivers they are the newest for my usb 3 port. and my internal drive is relatively fast, in hd tune it achieved an average of 80 mb/sec transfer rates.

Im going to return my enclosure and get a new one, thanks for the help again!

 

Unless you're transferring a single large file, your speeds are pretty much normal. You probably will want to look at the entire thread, but this specific post lists speeds pretty much on par with yours. Also check the post 2 posts below it.