SSD slower than HDD slower than 3 GB/s S-ATA II ?

[alan-0000]

Does anything seem to be wrong with my system ?

Windows does boot much faster since an SSD was added and C:\ was installed on the SSD instead of the HDD
but Disk Performance shows the SSD as being slower than the HDD.

HDS Disk Performance shows :-

OCZ SSD 55.9GB :-
Transfer Rate Information
Average Transfer Rate,10 KB/s
Maximum Transfer Rate,"125,355 KB/s"
Average Disk Activity,0.00 %
[178x DVD Write Speed]"

Samsung HDD 931.5 GB
Transfer Rate Information
Average Transfer Rate,94 KB/s
Maximum Transfer Rate,"160,288 KB/s"
Average Disk Activity,0.01 %
Estimated Max. Transfer Rate,"172,353 KB/s [149x DVD Write Speed]"

I would expect the 3 GB/s SATA channels to handle up to 384000 KBytes per second,
so the HDD is using only half the SATA capability, and the SSD is coasting at one third of the SATA capability

I am puzzled by the SSD.

What is "Maximum Transfer Rate,"125,355 KB/s" - is it the largest rate that was observed during normal useage today ?
What is "Estimated Max. Transfer Rate,"205,500 KB/s " - is it your best guess based upon specific HDS tests ?
Why is the SSD slower than the HDD - is it because the Browser cache transfers on the HDD have a higher throughput potential than the thousands of C:\ system file re-writes that Windows is always busy with ?

I use Zentimo xStorage Manager for safe removal of Flash Drives. It includes speed tests which show me

OCZ-VERTEX2 ATA Device
C_OCZ_System (C:), 55.8 GB "NTFS"
Type of file Speed of reading Speed of writing
Small files (32.0 KB): 20.31 MB/s 15.27 MB/s
Medium files (3.0 MB): 116.27 MB/s 61.65 MB/s
Large files (100.0 MB): 160.26 MB/s 58.96 MB/s

SAMSUNG HD103SJ ATA Device
E_SAM_E (E:), 26.8 GB "NTFS"
Type of file Speed of reading Speed of writing
Small files (32.0 KB): 26.05 MB/s 15.50 MB/s
Medium files (3.0 MB): 78.29 MB/s 137.14 MB/s
Large files (100.0 MB): 108.32 MB/s 110.08 MB/s

Does all the above appear reasonable, or is some large bottleneck apparent ?

Regards
Alan

[hdsentinel]

Hi Alan,

I can confirm that the SSD is not slower than the hard disk.
The values you see are based on the current usage of the drives, by measuring the current performance occured during any file operations performed by the computer.

> What is "Maximum Transfer Rate,"125,355 KB/s" - is it the largest rate that was observed during normal useage today ?

Yes, exactly as you wrote: during any file operation, the highest measured speed today was 125,355 KB/s.
If any software (or the OS) only used smaller files, then this can be lower and with high disk activity, meaning that the bandwidth is "wasted". But if you begin performing a command with high disk activity (for example using Disk -> Surface test -> Read test in Hard Disk Sentinel or copy a file) then you'd immediately get the actual higher performance of the SSD.

> What is "Estimated Max. Transfer Rate,"205,500 KB/s " - is it your best guess based upon specific HDS tests ?

No. It is calculated by using the above line (the measured highest transfer rate) and the actual disk activity % measured during that disk operation.
The disk activity % shows how the drive is used during the actual file operations, just like as you can check CPU usage in Windows Task Manager.

For example, if the disk activity shows 33%, it means that the disk can perform 3 x faster (when the disk activity % would be 100%).

So (just an example) if you see "Maximum transfer rate = 100000 KB/s" and during that, the drive had 50% activity, then the est. max. transfer rate is 200000 KB/s.

These indicators can be used exactly to reveal bottlenecks in your system. For example, start copying a big file from the SSD to your hard disk. Then you'd immediately see that
- both devices will have almost same actual disk performance (just one is reading and one is writing)
- one of the devices will have 100% disk activity (which means its bandwidth is fully used, it can't really perform faster)
- the other device will have lower disk activity %, indicating that it can be faster (if the other device could perform faster as well)

> Why is the SSD slower than the HDD - is it because the Browser cache transfers on the HDD have a
> higher throughput potential than the thousands of C:\ system file re-writes that Windows is always busy with ?

According the measured transfer values (which yes, may be indicated that Windows is busy by reading/writing small files only) you may think so.
But please do not forget that because seek time is almost zero on the SSD, exactly reading/writing these small files can be much faster.

Please check the Help (press F1 when the Performance page opened) for further information.

[alan-0000]

Many thanks.
Now that I understand I am happy that everything is fine.

Regards
Alan