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Very slow copy speed, but good benchmark?!

Last response: in Storage
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March 8, 2012 9:37:32 AM

Hi everybody,

It was time for an upgrade, so I upgraded every component of my pc with one exception: my sata HDD. And guess what's causing problems now? :ange: 

The problem: When I copy something (like a folder of say...3 gb) from C: to D: (both are partitions from the same HDD) the copy speed starts at ~40 mbps and drops to 10-15 mbps in 5-10 seconds!
Now the weird part: When I do a benchmark with HDtune, I get 50-70 mbps! (Which should be okay)

My setup:
Samsung sp2504c sata HDD (250 gb) (approx. 3 years old)
AMD Phenom II X4 960T BE
Asrock 970 Extreme4
4 gb DDR3 RAM
Windows 7 32bit

Causes I've ruled out (I think):
- did an Error Scan and checked S.M.A.R.T. with HDtune, nothing out of the ordinary
- I discovered that a possible cause for slow speed could be a change from DMA to PIO mode. I checked the device manager and it says "UltraDMA6" for my HDD, so I ruled it out. Also the benchmark should be worse if this was the case.

Causes I've not ruled out completely:
- The drivers. I'm not quite sure if I installed the right drivers. I installed all drivers from the CD included with my motherboard (only one relevant to this seems to be the "AMD all in one" driver). Does this suffice? I searched for a more specific chipset driver on AMD's homepage but couldnt find any (AMD seems to be more interested in graphics these days...)
- Old age => hardware defect. The simplest explanation. This explains why I had the same bad copy rates (but also good benchmark) before my upgrade. But I'm hesitant to accept this when there's no apparent defect or sign in SMART.

Summary:Slow (15mbps) copy speed, good (60 mbps) benchmark, no apparent cause, why? :D 

Thank you in advance!
March 8, 2012 9:56:51 AM

Drive performance will degrade over time. You also have to take IO into consideration. A physical disk is only able to do so much at one time, haven't looked at the exact numbers of your drive. You are reading and writing to the same disk so that is using your IO for that device. This explains why your benchmark is so much higher.
March 8, 2012 10:00:42 AM

Copying from one partition of a hard drive to another partition on the same harddrive will always be slow.
The drive has to read, move heads ,write, move head, read, move head, write etc. etc,
The drive is constantly swapping from read and write operations
Try copying from one harddrive to another harddrive, transfers should improve dramatically.
March 9, 2012 4:53:52 PM

Well now I feel kind of stupid.

Thank you two!

Out of frustration I ordered a SSD ;D
!