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How it is possible



 
 
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  #1  
Old March 7th 21, 09:12 PM posted to alt.comp.os.windows-10,alt.comp.hardware
micky
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Posts: 28
Default How it is possible

How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.


In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true. Only the PNY is so fast, and for less money. Does PNY
know something the others don't know.
  #2  
Old March 7th 21, 09:39 PM posted to alt.comp.os.windows-10,alt.comp.hardware
Jeff Barnett
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Posts: 6
Default How it is possible

On 3/7/2021 2:12 PM, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.


In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true. Only the PNY is so fast, and for less money. Does PNY
know something the others don't know.


I have two suggestions: 1) follow the two URLs you provided and read
carefully - there is little difference between the two advertised read
speeds and 2) note that MB and Mb are different by a factor of eight as
are GB and Gb.

Confusion between the latter two has many proud computer scientist
bragging about their Gigabyte LAN; it's really Gigabit and that's quite
different.
--
Jeff Barnett
  #3  
Old March 7th 21, 10:39 PM posted to alt.comp.os.windows-10,alt.comp.hardware
David W. Hodgins
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Posts: 147
Default How it is possible

On Sun, 07 Mar 2021 16:12:25 -0500, micky wrote:

How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.


The first drive has a read speed of 500 Megabytes Per Second. The second 535, so
only slightly faster.

A sata iii Hardware Interface works with a sata iii controller that supports a max
bus speed of 6 Gb. See https://en.wikipedia.org/wiki/Serial_ATA

The first drive is actually a sata ii drive, the second sata iii.

The term "Style" has no technical meaning. It's just a marketing term. The hardware
interface speed tells you whether it's sata, sata ii, or sata iii.

Newer drives are often lower in price per MB than older ones.

Regards, Dave Hodgins

--
Change to for
email replies.
  #4  
Old March 7th 21, 11:30 PM posted to alt.comp.os.windows-10,alt.comp.hardware
J. P. Gilliver (John)[_3_]
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Posts: 24
Default How it is possible

On Sun, 7 Mar 2021 at 16:12:25, micky wrote (my
responses usually follow points raised):
How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

[]
In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true. Only the PNY is so fast, and for less money. Does PNY
know something the others don't know.


Even leaving aside Jeff's point about bits versus bytes, speed isn't the
only important parameter for and SSD: there are probably many, but the
one that bugs me is the tolerated number of writes - which for the same
size SSD in the same machine/use, more or less maps to lifetime. You
also need to know how they behave when they reach their end of life: do
they continue trying to work (I don't think any), switch to read-only,
or just become a brick (at least one make/range does).
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)[email protected]+H+Sh0!:`)DNAf

A leader who keeps his ear to the ground allows his rear end to become a
target. - Angie Papadakis
  #5  
Old March 7th 21, 11:53 PM posted to alt.comp.os.windows-10,alt.comp.hardware
nospam
external usenet poster
 
Posts: 160
Default How it is possible

In article , J. P. Gilliver (John)
wrote:

Even leaving aside Jeff's point about bits versus bytes, speed isn't the
only important parameter for and SSD: there are probably many, but the
one that bugs me is the tolerated number of writes - which for the same
size SSD in the same machine/use, more or less maps to lifetime.


an ssd will very likely outlast the computer it's in, certainly a lot
longer than a spinning hard drive would have, and with a lot less noise
and heat.

You
also need to know how they behave when they reach their end of life: do
they continue trying to work (I don't think any), switch to read-only,


many do.

or just become a brick (at least one make/range does).


that's what backups are for.

drive failure is not unique to ssd. hard drives crashed, often without
warning.
  #6  
Old March 8th 21, 06:37 AM posted to alt.comp.os.windows-10,alt.comp.hardware
VanguardLH[_2_]
external usenet poster
 
Posts: 1,453
Default How it is possible

micky wrote:

How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.

In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true. Only the PNY is so fast, and for less money. Does PNY
know something the others don't know.


Do you know the difference between a bit and a byte? The first SSD says
its read spead is 500 MB/s (not 350 Mb/s). Multiply 500 MB/s by 8 to
get Mb/s second, and what do you get? 4 Gb/s which is not far from the
rating for the other SSD. In addition, the read spec for the PNY SSD is
not the 6 Gb/s you stated, but 535 MB/s as stated by the Amazon ad, so
its read speed would be 8 x 535 MB/s = 4.3 Gb/s.

You also need to consider the brand of the SSD. You are comparing
Kingston to PNY. PNY is okay, but has higher fail rates (from my
personal experience) than for Kingston. This is brand, not by whomever
is the actual manufacturer on which a brand slaps on its sticker.
Brands can contract specs with the manufacturer: the same maker can
produce different quality products based on what the customer specifies.

Is it your custom to compare normal retail price against sale price?
The PNY is on sale. It's non-sale price is $40 which is higher than the
Kingston product. Sales come and go. Compare apples to apples. Even
you know your grocery store has sales, but that's not the normal price.

Next time, drink a cup of coffee an hour before researching SSD prices
and specs. Don't compare MB/s to GB/s unless you convert. Don't
compare sale with non-sale price. Today, for you, was one those "Oops"
days.
  #7  
Old March 8th 21, 02:51 PM posted to alt.comp.os.windows-10,alt.comp.hardware
Chris
external usenet poster
 
Posts: 22
Default How it is possible

On 07/03/2021 21:12, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.


I'm not sure how you're reading them differently, but the 6Gbps is the
*interface* speed for SATA3 and is not the *device* speed. In terms of
device performance the PNY and Kingston are both ~500 Mbps so I don't
see where you get the 350 Mbps from?


In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.


Again, you're being spectacularly vague. With sites like Amazon it is
almost impossible to know what someone sees as it dependent on their
history, country of origin, what device they're viewing it on, time of
day, etc. so I'm not seeing what you're seeing.

On the Kingston page I see the comparison of four different models: A400
SATA 3 2.5", A400 M.2 SATA 3, A2000 NVMe, HyperX Fury RGB SSD. In terms
of read/write speed they're all fairly similar (450-550 Mbps) except the
'A2000 NVme which is 'upto 2000 Mbps'. Which is unsurprising given that
it uses the NVMe interface which is spectacularly fast.

In choosing an SSD you need make sure you get one which matches both the
form factor (2.5" internal, 2.5" external, M.2) and interface (USB,
eSATA, SATA, M.2, NVMe) that you need. Only then do you look at price.
  #8  
Old March 8th 21, 04:34 PM posted to alt.comp.os.windows-10,alt.comp.hardware
Paul[_28_]
external usenet poster
 
Posts: 1,467
Default How it is possible

micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.


In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true. Only the PNY is so fast, and for less money. Does PNY
know something the others don't know.


Wire speed of interface:

6 gbit/sec * 8/10 * 1/8 = 600MB/sec (goodput rate)

8B10B bits per bytes
encode
DC Balance

The SATA connector with the seven pins, uses packets. The packets
are like "request" and "acknowledge". There are time gaps between
packets.

Using tagged queueing, more than one transfer can be in motion
at once. This makes it easier for the link to find something
to do.

But the usable rate with the packets, is about 500MB/sec or
somewhere in that ballpark. No packet protocol goes
exactly at 100.0% of link speed. There's always gaps of
various sizes. Ethernet packets have pretty small gaps between
them, but other things are quite bad at that, like USB2
(60MB/sec) runs mass storage protocol at 35MB/sec max.

There are a few SATA controller chips (add-ons) that don't
actually run at full speed either. There's a Marvell chip
with SATA III interface, where it can only send the packets
at ~300MB/sec. But things like Intel or AMD Southbridge SATA III
aren't like that, and they're not likely to be the bottleneck.
All of the hardware in those cases, can be capable of 500MB/sec
of packets.

*******

The Flash can only read and write, so fast. There is the page size
and the number of Flash channels. Modern drives have relatively
low chip counts. A small drive only has a couple flash chips plus
a nice controller. This compares to a USB stick which has a couple
flash chips and a crappy controller. (The SSD has ARM processor
cores inside its controller. The USB2 chip has an 8085 in it.
Comparatively speaking.)

The quality metric is write speed. Maybe a drive reads at 535MB/sec
(according to the label), but writes at 300MB/sec. If the drive
uses TLC or QLC based flash, it may have a section of Flash
that functions as a small cache (20GB perhaps). Any sustained
transfer, runs at the cache speed. But if a sustained transfer
(a Macrium backup .mrimg file maybe) exceeds 20GB in size, the
drive slows down on writes a bit.

A Samsung with "MLC-like" 3DNAND, the old ones really were MLC-like
and the drive did not use a cache, and had uniform speed from end
to end. Some of this years Samsung drives claim to be MLC-like
but they're not. They're using Flash cache like everyone else,
and Samsung falls off its pedestal. When they're forced to do that,
that's evidence the thing is just TLC-like and not worth a dime extra.

*******

Let's take my laptop as an example of how you could easily
get carried away with this stuff.

I buy a SATA III SSD at 500MB/sec, worried about getting
shafted on a purchase. Yet, if we examine my SATA port in
the laptop, it actually runs at SATA II speed, or half that
(250MB/sec max). OK, so I buy a "300MB/sec write" SSD.
See the problem ? The SSD is actually perfectly adequate for
the job and "keeps up with the rate". Whether I ran either
the 500MB/sec write SSD or the 300MB/sec write SSD, I
can't tell the difference, because the laptop only
does 250MB/sec on the wire.

You didn't need the fancy one after all :-)

And that's how my laptop goes. Gave it a SATA III SSD.
Runs at SATA II rates. What a waste, eh ?

Well, it's not entirely a waste. The main improvement
in SSD drives, is the reduction in seek time. It takes
no time to "move the heads". It doesn't matter how
files are scattered over the SSD surface. Takes the same
time to read them, no matter where they are. This is why
we buy the SSD.

Whether it writes at 300MB/sec or 250MB/sec, there could
be times when that speed helps. But not every second the
SSD is sitting there on the desktop, does it need to run
flat out like that. Lots of SSD operation is in tiny
bursts. It's not the end of the world if the sustained
isn't "the speed of light". Sure, you notice the speed
when you bench with HDTune. But for a lot of other
uses, it's not so bad after all.

All the SSDs are better than spinning rust, because
of the seek time. You know how Windows 10 likes to
"scan stuff for fun". That's a lot of seeks. And that's
why we have SSDs for Windows 10. Speed up the boot
might be the most impressive thing it does, all day long.
Hardly noticed otherwise.

Paul
  #9  
Old March 10th 21, 07:03 AM posted to alt.comp.os.windows-10,alt.comp.hardware
T[_6_]
external usenet poster
 
Posts: 49
Default How it is possible

On 3/7/21 1:12 PM, micky wrote:
How it is possible that one SSD is 17 times as fast as another but costs
less? Both are 240G. Why would anyone buy the slower one (like I did
last summer)?

https://www.amazon.com/dp/B01N5IB20Q...t_details&th=1
350 Mb per second $35

https://www.amazon.com/PNY-CS900-240...01N5IB20Q?th=1
6 Gb per second $30 plus $6 for a bracket if you need one.


In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true. Only the PNY is so fast, and for less money. Does PNY
know something the others don't know.


Hi Micky,

You pay for what you get. If you want the least
likelihood the thing bricking on you, get a Samsung.

-T
  #10  
Old March 10th 21, 10:11 AM posted to alt.comp.os.windows-10,alt.comp.hardware
Carlos E.R.
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Posts: 8
Default How it is possible

On 08/03/2021 00.30, J. P. Gilliver (John) wrote:
On Sun, 7 Mar 2021 at 16:12:25, micky wrote (my
responses usually follow points raised):
How it is possible that one SSD is 17 times as fast as another but costs
less?** Both are 240G.** Why would anyone buy the slower one (like I did
last summer)?

[]
In the comparison list of the first one, 4 of them side by side, half
way to the bottom of the page, 2 others are the same speed as the first,
but the second one is 17 times as fast.

In a similar side-by-side comparison list on the second page, the same
thing is true.* Only the PNY is so fast, and for less money.* Does PNY
know something the others don't know.


Even leaving aside Jeff's point about bits versus bytes, speed isn't the
only important parameter for and SSD: there are probably many, but the
one that bugs me is the tolerated number of writes - which for the same
size SSD in the same machine/use, more or less maps to lifetime. You
also need to know how they behave when they reach their end of life: do
they continue trying to work (I don't think any), switch to read-only,
or just become a brick (at least one make/range does).


Which one bricks? That's important to know.

--
Cheers, Carlos.
 




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