Sign in to follow this  
cppguru

Deteriorating Hard Drive Access Times

Recommended Posts

I am not sure if anyone has noticed but there is an usual trend that seems to follow generally speaking with newer hard drives. A lot of websites give editor's choice award (or make similar recommendation) for newer 500 gb, 1 tb hard drives from Major vendors like WD, Hitachi, Seagate etc claiming robust speeds. The problem is that when I buy those "recommended" drives, they feel slower compared to the older hard drives I have in boot times and general workstation workload. So in order to find the root cause, I threw HD Tune tests and found out that 4K random read performance suffers in newer drives across the same RPM speeds (7200 in this case). Has anyone noticed this trend? It seems manufacturers are optimizing their firmware more for sequential speeds but random seek time suffers. I will be posting HD Tune screenshots to backup my claim.

Edited by cppguru

Share this post


Link to post
Share on other sites
o in order to find the root cause, I threw HD Tune tests and found out that 4K random read performance suffers in newer drives across the same RPM speeds (7200 in this case).
Generally head technology lags behind platter areal density, so seek times slow down until manufacturers put better heads into production and seek times then recover.

IIRC that was one of the major advantages of the WD Black when they were introduced, an improved head was used (relative to the WD Blue line) for better seek performance.

Of course the WD Black and WD Blue lines have languished for the past 2+ years... <_<

Share this post


Link to post
Share on other sites

If your OS is not Windows 7 you might suffer from performance issues with the 4k sectors that newer hard drive use. You might need to run an alignment utility or change some HDD jumpers.

Share this post


Link to post
Share on other sites

Generally head technology lags behind platter areal density, so seek times slow down until manufacturers put better heads into production and seek times then recover.

IIRC that was one of the major advantages of the WD Black when they were introduced, an improved head was used (relative to the WD Blue line) for better seek performance.

Of course the WD Black and WD Blue lines have languished for the past 2+ years... <_<

Honestly I don't think it has anything to do with the head technology. And I'm specifically referring to WD Blacks (I have their 250 GB, 320 GB version both perform very differently but employ the same head technology) compared to my aging 7200.11 500 GB from seagate, their 4K Random Times are much slower compared to my Seagate 7200.11 500 GB. Both drives spin at 7200 RPM.

Afterall if you think about it, the head's job is to read the smallest unit on the platters (I.e. a sector) - byte addressable, it is the control arm and the firmware that actually positions the head. I strongly believe that this is purely optimization problem in the software (firmware) - where Manufacturer's are readily increasing sequential speeds (good) but with increased random access times as a tradeoff. As promised, here are HD Tune - anyone interested please note the Random, 4K Random and Butterfly seek times.

If your OS is not Windows 7 you might suffer from performance issues with the 4k sectors that newer hard drive use. You might need to run an alignment utility or change some HDD jumpers.

All drives were formatted using Windows 7. Benchmark is done under Windows 7 64 bit as well.

The screenshots are attached.

1st Screenshot: My 4 year old Seagate 7200.11 500 GB

2nd Screenshot: The all new Hitachi Z7K500 7200 RPM 500 GB (compare the Random 49 IOPS to Seagate's 82 IOPS - that's almost twice as slow!!! for a 7200 RPM HD !!!)

3rd Screenshot: WD Black 250 GB

4th Screenshot: WD Black 320 GB (Notice the Random access time is much higher compared to the same generation WD Black 250 GB mentioned above which discredits the argument about different head technology. Both WD Black drives employ the same head technology because they are the same generation drives. Also noticed how much faster 320 GB Black is in Sequential speed compared to 250 GB Black).

post-78335-0-21578800-1340410000_thumb.p

post-78335-0-55389400-1340410009_thumb.p

post-78335-0-72914200-1340410016_thumb.p

post-78335-0-34574400-1340410103_thumb.p

Edited by cppguru

Share this post


Link to post
Share on other sites

Head positioning becomes trickier as the TPI goes up. It's dependent on a combination of mechanics and servo, whereas BPI improvements are more related to head technology. Obviously, there are design tradeoffs for which gets increased more to achieve a particular areal density.

I think what you're seeing is a combination of the inherent technical difficulties of keeping fast random access at higher TPI, plus the recent price increases in raw magnet materials (cost limitations). If most customers don't really care as much about random access as compared to sequential (particularly, with more enthusiast users opting for SSD), then it behooves the manufacturers to optimize for sequential performance, both from a design and cost standpoint.

Share this post


Link to post
Share on other sites

Head positioning becomes trickier as the TPI goes up. It's dependent on a combination of mechanics and servo, whereas BPI improvements are more related to head technology. Obviously, there are design tradeoffs for which gets increased more to achieve a particular areal density.

I think what you're seeing is a combination of the inherent technical difficulties of keeping fast random access at higher TPI, plus the recent price increases in raw magnet materials (cost limitations). If most customers don't really care as much about random access as compared to sequential (particularly, with more enthusiast users opting for SSD), then it behooves the manufacturers to optimize for sequential performance, both from a design and cost standpoint.

Well said. So now the question is for my hunt of a hard drive (prefer mechanical) in 2.5" form factor and 9.5mm height for laptop. I'm noticing there isn't a single 10,000 RPM hard drive because seeing the benchmarks - I see a velociraptor particularly interesting as it's access time is very low and sequential speed is still very high but they are not available for laptop. Any alternatives (Besides SSD ofcourse) ? What is the single most fastest 2.5" mechanic drive out there? Clearly the 320 GB Scorpio black is slower than it's 250 GB version and I prefer to stay away from hybrid drives because my usage does not involve frequently used data.

Edited by cppguru

Share this post


Link to post
Share on other sites

Probably pick whichever 7200 rpm 2.5" drive strikes your fancy. I doubt there will be huge differences between models, as customers that really want the higher performance either opt for SSD or hybrid drives and everyone else is going to be more cost-sensitive.

Share this post


Link to post
Share on other sites
What is the single most fastest 2.5" mechanic drive out there?
Click above a bit, go read the reviews published right here on Storagereview. :) It may not cover every single drive, but that oughta be a good place to start.

No, a Velociraptor will never work in a laptop-- even if they weren't too big (they're 12.5mm tall as opposed to 7mm or 9.5mm for a typical laptop drive), they require +12v power (standard laptop drives only draw on +5v), and they suck too much current for a laptop to handle.

As Mickey says... aside from reading the reviews... well... SSDs now are often under $0.75/GB on sale, that would be the next route. :P

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this