How do you compare speeds of SSD to hard drive?

[drealm]

I'm a tech newb and I'm trying to compare SSD and Hard drive speeds on new egg.

It seems Hard Drives are measures by:

- RPM (5400, 5900, 7200, 10000, 15000)
- Averager Seek Time (2.58ms, 3.0ms, 3.6ms ect)
- Averager Write Time (3.9ms ect)
- Latency (2ms ect)

Whild SSD's are measured by:

- Sequential Access - Write (600mb/s ect)
- Read: (Up to 870mb/s ect)
- Write: (Up to 780mb/s ect)

I don't get how to compare them. Hard drive is measured in MS, while SSD is measured in MB? Is there a common category to compare anyways? Bottom line I just wanna see which is faster. Thanks.

 

[RetiredChief]

SSD's are WAAAYYY faster.
What you need to look at for the operating system/program boot disk is the 4 K random read/writes. The link I provided (pg 22) has a chart - NOTE machanical HDDs can not even compete. Best SSD is like 40 times faster with the poorer ones around 13x faster!! For Storage of large files (ie Video (dot vobs ect and large jpeg files Pictures) Size is more important from a cost standpoint. also the difference for seq read/writes is not as great as the 4k random.

Good read
http://www.anandtech.com/storage/showdoc.aspx?i=3631&p=22

The main thing is the access time; SSd's around 0.1 mSec while HDDs are from 9 to 12 mSec. This is why the 4K random read/writes is so much faster.

Bottem Line: For a Boot disk you want a SSD (For Operating system and programs) for performance, coupled with a mechanical HDD for storage for your files.

 

[drealm]

Slow down cowboy! My pee sized brain is absorbing all that information!

Ok I suspected SSD was faster than Hard Drive, bravo. But how the hell do you compare them? Is there a common spec sheet? Or do they go by two totally different speed measurements? I mean just from looking at newegg's listed specs it doesn't look like there's common numbers to compare? I just want something easy.

 

[drealm]

The main thing is the access time; SSd's around 0.1 mSec while HDDs are from 9 to 12 mSec. This is why the 4K random read/writes is so much faster.

So is Sequential Access - Read and Sequential Access - Write on a SSD

The same as: Average Seek Time and Average Write Time on a Hard Drive?

---

Still seems confusing because SSD is measured in mb/s

While Hard Disk is measured in ms?

Just trying to find a common denominator.

 

[RetiredChief]

The spec as provided on say newegg, or even going to the manuf website is not very good to compare. Manuf tend to only emphase the Numbers that make their product look good. When comparing two diff products is is best to look for reviews that provide benchmarks and that provide a side-by-side comparision.

For example SSDs most offten only "advertise" their Seq numbers and access times - But there is a big differnce between them based on the controller used. Currently the Intel controller is best followed by the indilinx controller. This is why I look at articals like the one I pointed to. - It shows the difference between the SSD's, The BOTTOM HDDs are just there to show the dramatic imrpovement over HDDs. BUT when it comes to storage space per cost, HDDs are way more cost effective.

 

[cjl]

So is Sequential Access - Read and Sequential Access - Write on a SSD

The same as: Average Seek Time and Average Write Time on a Hard Drive?

---

Still seems confusing because SSD is measured in mb/s

While Hard Disk is measured in ms?

Just trying to find a common denominator.

Both SSDs and hard drives are measured in both MB/s and ms.

Typically, SSDs are around 200MB/s read, and 100-150MB/s write. Modern hard drives are around 120MB/s for both. This tells you how quickly it can read or write a file once it has started.

Access times on an SSD are around 0.05-0.5 ms. Hard drives range from 5-20ms (most 7200rpm desktop drives are around 12-14ms). This tells you how long it takes to find a file. This is where SSDs have a huge advantage.

 

[drealm]

The spec as provided on say newegg, or even going to the manuf website is not very good to compare. Manuf tend to only emphase the Numbers that make their product look good. When comparing two diff products is is best to look for reviews that provide benchmarks and that provide a side-by-side comparision.

For example SSDs most offten only "advertise" their Seq numbers and access times - But there is a big differnce between them based on the controller used. Currently the Intel controller is best followed by the indilinx controller. This is why I look at articals like the one I pointed to. - It shows the difference between the SSD's, The BOTTOM HDDs are just there to show the dramatic imrpovement over HDDs. BUT when it comes to storage space per cost, HDDs are way more cost effective.

Ok I gotcha. So basically newegg, ect, have lousy spec sheets. But on top of that there's other parts of the equation that influence the final specs.

Both SSDs and hard drives are measured in both MB/s and ms.

Typically, SSDs are around 200MB/s read, and 100-150MB/s write. Modern hard drives are around 120MB/s for both. This tells you how quickly it can read or write a file once it has started.

Access times on an SSD are around 0.05-0.5 ms. Hard drives range from 5-20ms (most 7200rpm desktop drives are around 12-14ms). This tells you how long it takes to find a file. This is where SSDs have a huge advantage.

I guess newegg for some odd reason just chooses to list specs by MB/s and ms instead of deciding on one listing format. For a newb this is confusing. Sounds like I'd have to dig deeper for finding common MB/s and ms specs if they aren't listed.

What I take away from this is SSD are better and faster in every way, except price. I take it hard drives will no longer be produced in five years and replaced with SSD? Perhaps even less time? It's an interesting trend to watch.

Thanks cheif and cjl.

 

[sminlal]

Have a look at the datasheet links on this Intel web page: http://www.intel.com/design/flash/nand/mainstream/technicaldocuments.htm

On page 8 of the datasheet for the 34nm products (that's the current, "G2" generation of Intel's SSDs) the latency (also known as "Access Time") is listed as 65 usec for reads - that's 0.065 milliseconds, well over 100X faster than a typical hard drive.

The downside of SSDs are price and capacity. SSDs are getting bigger with each generation, but mechanical hard drives are, too. Hard drives will continue to be produced for the foreseeable future because they're unsurpassed for bulk storage. For example, collections of audio and video recordings don't need anything special in terms of performance but do require a lot of space.