SSD-HDD Question

On 02/10/2012 07:35, Timothy Daniels wrote:
"Yousuf Khan" shared his thoughts on SSDs:
[ ...... ]

Have you ever thought of using a small capacity SSD
for the pagefile?

Is it implicit in your discussion that you've maxed out
your RAM (which can be seen a fast pagefile)?


No, RAM cannot be seen as a "fast pagefile". A pagefile can be seen as
a slow expansion to RAM for some purposes, which is a different matter.

Small capacity SSDs are not a great idea for pagefiles, especially ones
that are heavily used - small SSDs usually have more limited controllers
and have less cells to spread the wear, and you can get wear-out effects
(or at least slowdowns) that you would not see with a larger and better
SSD. And given the price of ram these days, you are probably cheaper
with real ram than a dedicated small SSD for swap.

"David Brown" wrote:
Timothy Daniels wrote:
"Yousuf Khan" shared his thoughts on SSDs:
[ ...... ]

Have you ever thought of using a small capacity SSD
for the pagefile?

Is it implicit in your discussion that you've maxed out
your RAM (which can be seen a fast pagefile)?


No, RAM cannot be seen as a "fast pagefile". A pagefile can be seen as
a slow expansion to RAM for some purposes, which is a different matter.

Small capacity SSDs are not a great idea for pagefiles, especially ones
that are heavily used - small SSDs usually have more limited controllers
and have less cells to spread the wear, and you can get wear-out effects
(or at least slowdowns) that you would not see with a larger and better
SSD. And given the price of ram these days, you are probably cheaper
with real ram than a dedicated small SSD for swap.


OK, then what is the best medium for a pagefile once RAM has been
maxed out? With a large amount of RAM, wouldn't an SSD dedicated
to a pagefile see only infrequent usage?

*TimDaniels*

On Tue, 2 Oct 2012 10:30:58 -0700, "Timothy Daniels" wrote:

"David Brown" wrote:
Timothy Daniels wrote:
"Yousuf Khan" shared his thoughts on SSDs:
[ ...... ]

Have you ever thought of using a small capacity SSD
for the pagefile?

Is it implicit in your discussion that you've maxed out
your RAM (which can be seen a fast pagefile)?


No, RAM cannot be seen as a "fast pagefile". A pagefile can be seen as
a slow expansion to RAM for some purposes, which is a different matter.

Small capacity SSDs are not a great idea for pagefiles, especially ones
that are heavily used - small SSDs usually have more limited controllers
and have less cells to spread the wear, and you can get wear-out effects
(or at least slowdowns) that you would not see with a larger and better
SSD. And given the price of ram these days, you are probably cheaper
with real ram than a dedicated small SSD for swap.


OK, then what is the best medium for a pagefile once RAM has been
maxed out? With a large amount of RAM, wouldn't an SSD dedicated
to a pagefile see only infrequent usage?

Paging may be more frequent than you think. Using Resource Monitor
last night during first backup operation on a new Win7 x64 install on
a box with 6GB memory: Memory was fully used for buffers, 0 free at
times and paging file accessed at +100kB/s on an intermittent basis.

About 4.5GB buffer memory in use!

There was a fair bit of write activity to the C: on SSD, about 5MB/s
into hidden areas, before peak 100MB/s writes to the backup HDD.

Paging file on a different spindle than the backup HDD.

Grant.

*TimDaniels*

On 02/10/2012 19:30, Timothy Daniels wrote:
"David Brown" wrote:
Timothy Daniels wrote:
"Yousuf Khan" shared his thoughts on SSDs:
[ ...... ]

Have you ever thought of using a small capacity SSD
for the pagefile?

Is it implicit in your discussion that you've maxed out
your RAM (which can be seen a fast pagefile)?


No, RAM cannot be seen as a "fast pagefile". A pagefile can be seen
as a slow expansion to RAM for some purposes, which is a different
matter.

Small capacity SSDs are not a great idea for pagefiles, especially
ones that are heavily used - small SSDs usually have more limited
controllers and have less cells to spread the wear, and you can get
wear-out effects (or at least slowdowns) that you would not see with a
larger and better SSD. And given the price of ram these days, you are
probably cheaper with real ram than a dedicated small SSD for swap.


OK, then what is the best medium for a pagefile once RAM has been
maxed out? With a large amount of RAM, wouldn't an SSD dedicated
to a pagefile see only infrequent usage?


With a large amount of RAM, swap is usually not used much (but as Grant
says, Windows will use it a little even when there is no point in doing
so - and Linux will sometimes move old pages into swap if it feels the
ram is more useful as file cache). But you want fast access to swap.
So the best place is on an SSD for speed, on a big SSD (not a small one)
to avoid issues of wear and get the best use of the SSD's garbage
collection, and to get the fastest throughput (big SSDs are usually
faster). It is a serious waste of money to dedicate an SSD to swap -
you will almost certainly be better off spending that same money on more
ram. So put your swap file or swap partition on the same SSD(s) you
normally use.

If you don't have a big SSD with enough free space for swap, then put it
on a hard disk - in which case you want the least used fast hard disk as
your main swap.

On Tue, 2 Oct 2012 10:30:58 -0700, "Timothy Daniels"
wrote:

"David Brown" wrote:
Timothy Daniels wrote:
"Yousuf Khan" shared his thoughts on SSDs:
[ ...... ]

Have you ever thought of using a small capacity SSD
for the pagefile?

Is it implicit in your discussion that you've maxed out
your RAM (which can be seen a fast pagefile)?


No, RAM cannot be seen as a "fast pagefile". A pagefile can be seen as
a slow expansion to RAM for some purposes, which is a different matter.

Small capacity SSDs are not a great idea for pagefiles, especially ones
that are heavily used - small SSDs usually have more limited controllers
and have less cells to spread the wear, and you can get wear-out effects
(or at least slowdowns) that you would not see with a larger and better
SSD. And given the price of ram these days, you are probably cheaper
with real ram than a dedicated small SSD for swap.


OK, then what is the best medium for a pagefile once RAM has been
maxed out? With a large amount of RAM, wouldn't an SSD dedicated
to a pagefile see only infrequent usage?
Using SLC rather than MLC typically results in faster performance,
fewer "stalls", and more than 10 times longer life.

The bad news is that the cost of SLC is typically 10 or more times the
cost per bit for MLC, even though a simple analysis indicates the cost
should only be 2 or 3 times as much.

The good news is that some nominally MLC devices seem to have SLC
type performance when slightly less than 1/2 of the nominal capacity
is allocated to partitions.

One such device is OCZ Vertex 4 using firmware 1.5.

This is what Toms Hardware says:

http://www.tomshardware.com/reviews/vertex-4-firmware-benchmark,3245-8.html
Naturally firmware changes and newer versions of the hardware may
behave differently, but in the meantime it seems like the OCZ
Vertex 4 at about 1/2 capacity will work well.

Disclaimers:
1. I have no connection with OCZ or Toms Hardware.
2. I have several Vertex 4 256GB and 512GB SSDs and they behaved well
in my tests with firmware 1.4, but I haven't tried firmware 1.5 and
running at 1/5 capacity, so I am only pointing out the experiences
that others have reported on the web.

However:
1. I have been using an OCZ Vertex 3 MAXIOPS as my system drive on
one of my Windows 7 systems for more than 6 months. Paging and
hibernation are on the Vertex 3 MAXIOPS and there have been no
problems, but I don't actually do much paging or hibernation.
*TimDaniels*

"David Brown" wrote:
[ ... ]
With a large amount of RAM, swap is usually not used much (but as Grant
says, Windows will use it a little even when there is no point in doing
so - and Linux will sometimes move old pages into swap if it feels the
ram is more useful as file cache). But you want fast access to swap.
So the best place is on an SSD for speed, on a big SSD (not a small one)
to avoid issues of wear and get the best use of the SSD's garbage
collection, and to get the fastest throughput (big SSDs are usually
faster). It is a serious waste of money to dedicate an SSD to swap -
you will almost certainly be better off spending that same money on more
ram. So put your swap file or swap partition on the same SSD(s) you
normally use.

If you don't have a big SSD with enough free space for swap, then put it
on a hard disk - in which case you want the least used fast hard disk as
your main swap.


OK, for some reason, everybody misses the clause about RAM being
maxed out. So, again:

Assuming that the RAM is at the maximum amount supported by the
motherboard, and you wanted the maximum speed to process large
files (such as video files), would you used the main SSD, a dedicated
SSD, or a partition on a dedicated magnetic rotational HD partition for
the swap file?

*TimDaniels*

On Wed, 3 Oct 2012 17:32:58 -0700, "Timothy Daniels" wrote:

"David Brown" wrote:
[ ... ]
With a large amount of RAM, swap is usually not used much (but as Grant
says, Windows will use it a little even when there is no point in doing
so - and Linux will sometimes move old pages into swap if it feels the
ram is more useful as file cache). But you want fast access to swap.
So the best place is on an SSD for speed, on a big SSD (not a small one)
to avoid issues of wear and get the best use of the SSD's garbage
collection, and to get the fastest throughput (big SSDs are usually
faster). It is a serious waste of money to dedicate an SSD to swap -
you will almost certainly be better off spending that same money on more
ram. So put your swap file or swap partition on the same SSD(s) you
normally use.

If you don't have a big SSD with enough free space for swap, then put it
on a hard disk - in which case you want the least used fast hard disk as
your main swap.


OK, for some reason, everybody misses the clause about RAM being
maxed out. So, again:

I don't think we're missing the point. I described an observed
situation where a machine with 6GB and only ~1.5GB in use will use
the rest of memory for buffers, to the point of needed paging file
access.

Assuming that the RAM is at the maximum amount supported by the
motherboard, and you wanted the maximum speed to process large
files (such as video files), would you used the main SSD, a dedicated
SSD, or a partition on a dedicated magnetic rotational HD partition for
the swap file?

Use the method with least harmful impact on performance

HDD seek time will kill paging performance if there's user data
I/O happening on the same spindle. SSD doesn't have seek time
to slow it down, so then one considers wear.

Monitor performance with your own application mix.

Free memory is used for buffers, once you have enough memory for
the current OS + application's need, memory will get maxed out
for buffers and paging file will not see much activity.

If you have a machine aggressively paging (swapping), add memory.

I'm not sure there's a one size fits all solution. Still arguing
with myself

Grant.

*TimDaniels*

"Grant" replied:
[ .... ]
If you have a machine aggressively paging (swapping), add memory.


AGAIN, assume that the memory has been maxed out, i.e. the
motherboard cannot accommodate any more RAM. What would
you use if you needed more room for a pagefile - a dedicated SSD
or rotational magnetic HD(s)?

*TimDaniels*

On 04/10/2012 02:32, Timothy Daniels wrote:
"David Brown" wrote:
[ ... ]
With a large amount of RAM, swap is usually not used much (but as
Grant says, Windows will use it a little even when there is no point
in doing so - and Linux will sometimes move old pages into swap if it
feels the ram is more useful as file cache). But you want fast access
to swap. So the best place is on an SSD for speed, on a big SSD (not a
small one) to avoid issues of wear and get the best use of the SSD's
garbage collection, and to get the fastest throughput (big SSDs are
usually faster). It is a serious waste of money to dedicate an SSD to
swap - you will almost certainly be better off spending that same
money on more ram. So put your swap file or swap partition on the
same SSD(s) you normally use.

If you don't have a big SSD with enough free space for swap, then put
it on a hard disk - in which case you want the least used fast hard
disk as your main swap.


OK, for some reason, everybody misses the clause about RAM being
maxed out. So, again:

Assuming that the RAM is at the maximum amount supported by the
motherboard, and you wanted the maximum speed to process large
files (such as video files), would you used the main SSD, a dedicated
SSD, or a partition on a dedicated magnetic rotational HD partition for
the swap file?


I didn't miss the point, and the answer is the same. The only part you
can really complain about is the sentence "It is a serious waste of
money to dedicate an SSD to swap - you will almost certainly be better
off spending that same money on more ram." If you prefer, just think
of it as "It is a serious waste of money to dedicate an SSD to swap".
The same recommendations still apply - prefer swap on your main SSD, or
use space on a little-used HD if you don't have a main SSD.


To give a more elaborate answer about how to get maximal performance out
of a system that does not have enough ram (because you can't put more
ram in), the answer is that you can /never/ get decent performance.
Even at its best, swap is thousands of times slower than ram. You have
swap so that the OS can move less-used pages out of ram and make better
use of the ram - you do not have swap so that the computer can pretend
it has more memory.

So if you want to process these large files without enough memory, you
leave the machine to chew them overnight.

Alternatively, you upgrade the system in some way to allow you to put in
more memory. But any attempt at spending money to get "fast" swap is
useless - all you can get is "not quite so painfully slow" swap.

David Brown wrote:

Alternatively, you upgrade the system in some way to allow you to put in
more memory.

Maybe the original poster should say how much ram he now has.

What is the maximum amount of ram that any Windows 7 compatible
motherboard can accept? The last time I shopped for motherboards (a
few months ago), I found some that would use 32 gigs. Are there any
that can take 64 or 128 gigs?
--
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happy. The human is happy because he thinks the cat is sitting on him/her
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