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SSD raid & secondary SSD page file drive

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September 28, 2009 5:31:43 PM

Anyone have some advice on the below setup?

I'm planning on building a new gamer system built around the EVGA X58 SLI #132-BL-E758-A1.

I'm considering using 2x Crucial CT128M225 2.5" 128GB SATA II MLC Internal Solid state disks in raid 0 for the OS boot and applications. Possibly partitioned into C: and D: drives for OS/application separation.

Additionally, I'd like to put the page file onto a separate Crucial CT64M225 2.5" 64GB SATA II MLC Internal Solid state disk.

Memory will be 12GBs of: CORSAIR DOMINATOR 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit Desktop Memory Model TR3X6G1600C8D

OS: Win 7 64bit

Now, here is where I'm wondering how to squeeze out the best performance from a system like this.

Should I use the on-board raid controller from the MB? Or would a third party raid controller be better?

My logic for using a separate SSD drive for the page file is the heavy use it will endure from games paging to the drive. I'm thinking this will spare the main raid 0 drives from excessive read/writes, thereby extending the optimum operating life of the primary drives.

The page drive could be replaced periodically as its performance degrades (if applicable).

I welcome constructive criticism.

Thank you.
September 28, 2009 6:02:34 PM

I dont think you can do this - page file has to be withing the windows partition (may be wrong, no expert)

Also remember reading that having page file off when using SSD helps as their wright speed is not thel ightning fast part.
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a c 415 G Storage
September 28, 2009 11:44:49 PM

SSDs themselves will give you a huge performance boost for booting and loading your programs, so you probably don't really need RAID unless the point is to get a larger OS volume to hold all the apps you plan to install.

With 12GB of memory I strongly doubt that your pagefile will be very busy at all, so I'd either just disable it altogether or leave it on the system drive. BUT - I could be wrong about this if you're using very large 32-bit games that can't take advantage of memory beyond 2 or 3GB.

It IS possible to move the pagefile to a different disk via (the following is for Windows 7):

Start -> Right-click on Computer -> Properties -> Advanced System Settings-> "Advanced" Tab -> Performance "Settings..." button -> "Advanced" tab -> Virtual Memory "Change..." button.
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September 29, 2009 3:26:56 AM

After some reading on the page file topic. There are a full range of choices to be had about virtual memory (page file) settings and how to get the most out of Windows. Some are based on ideal technical principles. While others are based on real world experimentation and implementation.

On one side of the range: If you have a huge amount of memory, disable the page file.

Standing in the middle of the fence are those who say let windows manage the page file at it's default 1:1.5 value. As many programs are engineered to gobble up huge amounts of virtual memory (Adobe Photoshop comes to mind - which I use). These types of programs, when no page file is present, will consume and dedicate many gigabytes of RAM. In many cases, these programs don't actually use the memory but reserve virtual memory just in case it's needed. This would definitely impact multi-tasking if large amounts of RAM are reserved for one program.

I also use virtualization of various operating systems which themselves reserve and share memory.

To the far end of the other side of the page file spectrum are the those who say modern versions of Windows benefit from using a secondary hard drive dedicated to virtual memory.

I've built many systems from scratch having many different outcomes. I've personally found Windows to generally behave a bit better when there is a page file present. Additionally, I've noticed when using RAID 0, partitioning the RAID volume and then dropping the page file onto a logical partition, the system does indeed appear to be snappier and stable - stability being the main issue for me personally.

I'm also looking into the Corsair SSDs.

Another possible SSD configuration: 2x Corsair Extreme Series CMFSSD-32D1 2.5" 32GB SATA II MLC Internal Solid state disk - 1 for the OS and 1 for the page file. And 1 Corsair Extreme Series CMFSSD-128D1 2.5" 128GB SATA II MLC Internal Solid state disk for applications.

I generally use an external NAS device to store music and video files. So I don't require much beyond 150 GBs of hard drive space for a PC.

Since it appears RAID 0 wouldn't give much of a performance boost for these drives, this modular type of arrangement might work nicely. If I need more space for applications, simply add another drive.

Also, I'm hesitant buying larger SSD drives due to the higher failure rates the larger drives seem to experience at this point in time.

From and old school stand point, RAID 0 seems very logical to me. But from a technology stand point, RAID 0 might not be the best option for a SSD based system. It's counter intuitive to the platter drive world of RAID but this is part of learning to accept new things and how they impact real world scenarios.

If anyone has some real world experience on these SSD RAID issues, please post here. I'd like to know how your SSD build(s) turned out.
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September 29, 2009 3:56:46 AM

This is a comment from a page file article.

Quote:
Do not put the pagefile on a different partition than Windows if it is on the same physical drive. Doing as the author suggests would improve the data transfer rate to the pagefile. But this is rarely a major factor in performance. The biggest factor is seek time, and to minimize this the pagefile must be as near as possible to the other files. Microsoft recommends putting the pagefile on the most active partition of the least busy disk.

The biggest myth is that the initial amd maximum size must be the same for optimum performance. This is simply not true. If the initial size is large enough to avoid virtual memory warnings there will be NO pagefile resizing and no fragmentation. For practical purposes you will have a fixed pagefile. But set the maximum at least twice this value. This gives all the advantages of a fixed pagefile, yet it is able to grow to meet unusual needs. After a reboot (or sooner) the pagefile will revert to it's initial size. At no time set the maximm larger than 4GB as 32 bit Windows can use no more. Incidentally, fragmentation in the pagefile is rarely a performance issue except in extreme cases.

A maximum value that is too small can severely impair performance. Also, do not disable the pagefile. In some cases this may improve performance but usually the reverse is true.

Larry Miller
Microsoft MCSA


According to Microsoft, assigning the page file to a separate disk is ideal. "Microsoft recommends putting the pagefile on the most active partition of the least busy disk."

The least busy disk my case would be the dedicated SSD. File fragmentation should be minimal in a modular drive scenario. This might be worth giving a try.

Generally, I use virtual PCs to run potential OS altering applications (which is almost everything). Nothing worse than installing some bloated program that throws files everywhere on the OS.
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a c 127 G Storage
September 29, 2009 11:52:59 AM

Rather than using RAID to enhance performance of your SSD setup, why not go for a better SSD instead? Intel's X25-M G2 (with 34nm production chips) is by far the best consumer SSD right now, and it might be alot faster than two Crucial/Patriot/OCZ SSDs in RAID0 in many cases.

Sure the sequential write of the Intel SSDs is only 75MB/s, but who cares about sequential speeds for their system disk? Its IOps what counts here, and with 30.000 random read IOps and 4.000 random write IOps both with very low latency, Intel is best-in-class for serving as a system disk. To compare: the fastest mechanical disks (10k / 15k rpm) do about 100-200 random read IOps.
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October 6, 2009 2:25:35 AM

sub mesa said:
Rather than using RAID to enhance performance of your SSD setup, why not go for a better SSD instead? Intel's X25-M G2 (with 34nm production chips) is by far the best consumer SSD right now, and it might be alot faster than two Crucial/Patriot/OCZ SSDs in RAID0 in many cases.

Sure the sequential write of the Intel SSDs is only 75MB/s, but who cares about sequential speeds for their system disk? Its IOps what counts here, and with 30.000 random read IOps and 4.000 random write IOps both with very low latency, Intel is best-in-class for serving as a system disk. To compare: the fastest mechanical disks (10k / 15k rpm) do about 100-200 random read IOps.


Your absolutely correct. I've been looking into the 2nd generation of Intel SSDs and they look very promising. I'll probably hold off on building this system until the first quarter of 2010. The Prices of the Intel drives should come down a bit to more reasonable levels? Lets hope :D 

I've changed some hardware in favor on the lower energy Lynfield CPU. Also, the graphics cards were chosen for their performance as well as their cool operating temperatures. I'm shooting for performance, reliability, cool temps, virtualization, gaming (primary game would be Diablo 3 when it comes out) and longevity for future applications (3 years into the future?).

So far this is what I'm looking at:

Corsair Obsidian Series 800D CC800DW Black Aluminum / Steel ATX Full Tower Computer Case

EVGA P55 FTW SLI 132-LF-E657-KR LGA1156 Intel P55 ATX Intel Motherboard

2 each - EVGA 512-P3-N871-AR GeForce 9800 GTX+ 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card

CORSAIR CMPSU-1000HX 1000W ATX12V 2.2 / EPS12V 2.91 SLI Ready CrossFire Ready 80 PLUS Certified Modular Active PFC Compatible with Core i7 Power Supply

Intel Core i7-860 Lynnfield 2.8GHz 8MB L3 Cache LGA 1156 95W Quad-Core Processor

CORSAIR XMS3 8GB (4 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMX8GX3M4A1600C9

OS Drive - Intel X25-M SSDSA2MH080G2R5 2.5" 80GB SATA II MLC Internal Solid state disk (SSD)

Apps & Page File Drive - Intel X25-M SSDSA2MH160G2R5 2.5" 160GB SATA II MLC Internal Solid state disk (SSD)

So far, this looks like a pretty solid setup. The MB has 3x bios for easy switching between gaming OC settings, stock everyday use and trying out the latest and greatest BIOS updates before committing them to the stable BIOS configurations. Not to mention, it won't bankrupt me in the process. :sol: 

I currently have a Dell 2209WA e-IPS 22" panel.

But am considering this NEC as its successor - which uses a S-PVA 22" panel- NEC Display Solutions P221W-BK Black 22" 8ms(GTG) Widescreen LCD Monitor 300 cd/m2 1000:1

The dell is wonderful for just about everything, but not sure about the NEC as of yet.
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a b G Storage
October 6, 2009 3:42:59 AM

This is SSD we're talking about here where concurrent read/write barely affects performance, unlike HDD. What that means is moving pagefile off to another drive will not help performance like it does for HDD.

As for RAID0, depends on your budget and how you utilise SSD to their maximum advantage against HDD. While SSD in RAID0 can increase more in % performance for most usage desktop patterns compared to HDD in RAID0, say if a takes only 8s to complete while two in SSD in RAID0 takes 5s, you are not going to notice the speed difference.
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October 8, 2009 2:25:42 PM

you'd be better of getting a 16GB SLC SSD, they will not wear out as fast and are faster for your Pagefile needs
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October 8, 2009 2:28:14 PM

P.S. there is no guarantee that SSD prices will come down as quick as you'd like, in fact, they have gone up recently. I ordered a Crucial 64GB M225 yesterday.... I'm looking into getting a small SLC SSD for my pagefile needs
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October 15, 2009 2:39:21 AM

WAIT CLOUD!!! DO NOT PROCEED!!!

I am in the same boat, and we can learn together.

I have been thinking about the same possibilities.

First, I don't have that many ideas but here we go.

The new corsair SSDs are getting some pretty good reviews. Now, if I am not mistaken tom's hardware had some info where they set up like 16 SSDs (intels) on a RAID card and the speed was SICK!!! It was like 5 or 6 GBs/sec. Looking for link:

http://www.tomshardware.com/reviews/ssd-6gb-raid,2388-2...

That is actually the second type test they ran.

Now to the comment above that says a difference in 8secs and 5secs is not worth it. Well, true you will have to do a cost benefit analysis, but if you want gaming with almost no loading, if the money is on the tree we might as well pull it off. So, what if that 8secs turn into 2 or less???? Worth it? Maybe!!!

So here are a few of my thoughts:

Oh by the way, you MUST consider the 1366 instead of the 1156 CPUs. If you research the upcoming 6 core processors (i9s) from Intel, the new 6 cores will be 1366. Therefore, purchasing the correct board upfront "Should" allow for the option down the road of picking up a 6 core processor. Just thought I would mention that for there may be other reasons you went with a 1156. There seems to be some decent 1366 motherboards out there too, even one at a "reasonable" price with decent reviews. Asrock anyone? I am attempting to find the 1366 link with the 6 core i9 info. Wikipedia has it, but looking for the more user friendly site :|

Currently, I am planning on going with a i7 920. I will OC that at 3.6Ghz give or take a few. I am going with a Artic Cooling Freezer 7 Pro REv.2 92mm cooling fan. I am not a "watercool" person. Limited knowledge but working on it. You can get an i7 920 for a good price. I think it has a good speed/price point in my opinion.

Now back to SSDs. The corsairs for the new models have a 128 and 256. My thought was getting two 128s and RAID0 them. However, I am thinking another SSD for page file, but as with you I am not sure of the real world benefits. I have also thought of 4 128s in RAID0 and have everything on that drive. That option would probably still give me room for a SATAII SSD (page file) and room for a 1TB 7200 HDD (not needed for gaming, but a possibility) for other stuff. The use of 2 and 4 128s is obviously for getting faster HDD performance. And many sites are saying that faster drivers are one of the major speed improvements you can make. I guess with 2 and 4 you are increasing your risk of drive failure due to one drive affecting everything, but this will be a PC first and foremost for Gaming. I have a laptop for everything else.

Also, as far as Video cards go, for Diablo 3...it might be beneficial for a better one. However, as I type I can't remember what you mentioned about the cards...I think you had a 9800. Plus, I haven't looked at the recommended hardware for Diablo 3 but still, I am looking at either the ATI 5870 (expensive) or one of the new Nvidia's when they come out (probably mega expensive). So I will start first with the 5870. Then I have the option of Crossfire with another identical card. [Okay looked at the tentative Diablo 3 recommended specs and the 9800 appears well sufficient. Maybe not Doom 4, but Diablo seems well within the 9800s wheelhouse:

http://www.destructoid.com/rumortoid-diablo-iii-release... (again this is a guess)

Not sure what else to say right now, but hope you are still around, and we can learn from each other.

:) 

Another idea is what about seperating OS from APPs. Or will a 2 or 4 SSD setup even need that. Read some of the new Corsair reviews. It sounds good, and doesn't appear to have stutter issues. Also, Intels are supposedly nice. However, Corsairs have a better speed rating I think, but as with everything our mileage may very.

Also: Found this an interesting read:

http://www.zdnet.com.au/blogs/motherload/soa/Intel-s-34... file ssd os installed where&fr=yfp-t-158&toggle=1&cop=mss&ei=UTF-8

I am thinking that a RAID option would help his "concerns" but I have no real world evidence, so we shall see. Also, someone commented about the page file in the comments section and it appears that another person said with enough RAM page files are not needed. I am not sure, but thought I would attach this link.
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a c 415 G Storage
October 15, 2009 3:08:57 AM

Onrac said:
I am thinking another SSD for page file, but as with you I am not sure of the real world benefits.
The page file is used for program code and data that will not fit in RAM. Accessing the page file is MUCH slower than accessing RAM, even if you use an SSD raided 6 ways from Sunday. You're a lot better off spending the money to make sure you have sufficient RAM rather than trying to speed up the page file.
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October 15, 2009 3:43:27 AM

Well, maybe a 12GB system would be worth it instead of just going with less RAM. Forget about an additional SSD, or use an extra SSD in the RAID0. I am thinking 4 128GB SSDs in RAID0, one HDD storage drive, and 1 Blu-Ray drive for my 6 SATA connections. :\

It makes since, but if I lay this money down, and I get slowmo: I will cry.

:) 
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October 15, 2009 6:57:08 AM

Onrac said:
Well, maybe a 12GB system would be worth it instead of just going with less RAM. Forget about an additional SSD, or use an extra SSD in the RAID0. I am thinking 4 128GB SSDs in RAID0, one HDD storage drive, and 1 Blu-Ray drive for my 6 SATA connections. :\

It makes since, but if I lay this money down, and I get slowmo: I will cry.

:) 


Yes, it would seem we're in the same SSD boat! lol

We both seem to be looking for an ideal solution to theory and real world application. Theories are chalk board ideas that - according to sound principles - should apply to real world outcomes. But this is not always the case.

To pagefile or not to pagefile. To RAID or not to RAID SSDs. One thing is for sure, I'm not going to rush into a spending binge until I'm fairly confident the outcome will match the theory to within a decent tolerance.

As far as LGA 1366 vs the 1156. If I was wanting to 3x graphic cards with 16/16/8 lanes, the 1366 would make sense. But, I'm not planning on going beyond 2x graphics cards and the 1156 setup would be just fine for really nice 16/8 lane nvidia setup. Primarily, the i7-860 has a 90w TDP rating, with 2x 9800GTX+ cards equates to very good over clocking while still having very cool temps.

I really don't want to have to run an AC just to keep my PC cool, lol. As is the case with my current - and aging - Intel 955x board and 940 D chip (upgraded from an 830 D). I'm running a single EVGA 9800GTX+ (upgraded from a BFG 7800GT), 2 gigs of OCZ gold memory with 4x Hitachi Desk star SATA II drives in RAID 0 (Running these drives in RAID 0 hard for 3 years no problems at all). (XP is the OS)

Using this setup, nothing is over clocked due to the Intel board, my CPU Idle temps are between 33-37C, depending on the ambient temp. Load temps are usually about 10-12C hotter. The video card runs very very cool and using 2 of them in SLI will give comparable results to a single 290 series card - which will run much hotter, not to mention be more expensive.

With a nicely planned i7-860, SLI 9800GTX+ based system. For around $2,500, the results would be a balance of price, performance, and easy cooling. I would like to keep load temps below 40C at 23-24C ambient room temp. That's my theory anyway at this point.

But back on topic - SSD RAID.

One reason I'm so concerned about pagefile, SSDs and what-not is for this basic reason. Once an SSD begins rewriting to already written sectors of the drive, there is a problem. The problem being that orphan bits of data stay on the drive, degrading performance over time. Now, apply this to a heavy rewriting application such as a virtual PC - which I use often.

As far as I know, OCZ drives are the only ones available that can utilize the Samsung orphan file cleaning utility. Does Intel have anything comparable? IS this a problem on Intel drives? While all the hoopla is about how great SSDs are, I still think about the downsides of an SSD.

Hence my rational behind separating the drives. Or at least some of the rational.

One possible scenario I've been thinking about: 2x SSD 80gig Intel drives in RAID 0 for the OS and apps. A 3rd SSD 80gig for virtual hard drives and pagefile. Now, this third drive should take most of the rewrites, no? Once I build up a solid VPC hard drive image, back it up to my NAS unit. If the 3rd SSD should slow down, re-format, wa-la, back to a clean slate.

Since the primary RAID 0 SSD array will be reading most of the time, rewrites shouldn't be that much of an issue.

I don't know, there are many things to consider here. Technology is moving so fast now, its hard to keep up with it all. The i9 chips? While they will likely be compatible with current MBs, I'm pretty sure Intel will have a bigger and better carrot to dangle in our faces to buy the next gen of MBs. :sol: 

It will be the same as my current Intel 955x 940 D setup. When I bought the MB, it was basically designed for the 800 D series chips. Along comes the 900 D series, that through a BIOS update, the 955x boards accept certain 900 series chips. But then came along the 975x boards that spouts off better performance and features. I'm sure the i9 will be much the same.

In all honesty, I don't think too much about upgrading anything on a system these days. By the time most of us think about upgrading something, our PC is so outdated, it makes more sense in many instances to build a new rig.
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a c 127 G Storage
October 15, 2009 1:52:10 PM

Disable the page file and get an Intel SSD; buying any other SSD is a shame for your money because it could be spent better. There is no SSD that beats Intel; because Intel don't let their competitors use their controller chip, with some minor exceptions.
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October 15, 2009 2:01:26 PM

So for just under $1,200 I can have 4 128GB Intels in RAID0.

[Passes out]

I think I might wait for version G3 of the intels. However, I have the itch to build right now. ARRGGGHHHHH!

However, after reading more I have to agree with you Sub Mesa. Intel appears the way to go.

Also, is the cleaning system the TRIM feature? I think G2 intels have that. Also, I have read that Windows 7 deals better with SSDs. They turn off a few things that slow down SSDs....indexing and ....something else. I am at work, so can't find links now, but the pursuit continues. Hope to hear about G3s soon. Unless the itch becomes too much to bare :|
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a c 127 G Storage
October 15, 2009 2:06:14 PM

128GB? Don't you mean the 160GB ones? Generally i would get the 80GB; these are as fast as the 160GB there is little difference. But you can put them in RAID0.

So 4x 80GB = 320GB and it would cost about $250 x 4 = $1000; not that bad is it?

I agree though, it would be nice if the cost per GB would go down further. But the performance is here already; Intel SSDs don't have any particular weaknesses; other SSDs do have them especially random write.
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October 15, 2009 2:38:56 PM

Ooops! You are correct! I am still thinking the Corsairs. 80x4 instead of the 128x4 I mentioned.
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a c 415 G Storage
October 15, 2009 6:14:59 PM

Onrac said:
I think I might wait for version G3 of the intels.
Forgive me, but from your posts I'm kind of getting the impression that you'll always want something that's just out of your reach. If I were you I'd just go ahead and buy one Intel SSD right now and use it as your boot drive. If you can't fit everything you want onto it, just install the other stuff on a hard drive. You'll get a pretty big bang for your buck. No, it won't be as fast as a 4-drive RAID set, but it will be a lot better than the HDD-only system you'd be living with while waiting for an "ultimate" solution...
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a c 127 G Storage
October 15, 2009 6:21:09 PM

I agree, with just one SSD you get alot of the benefits. The tradeoff here is that not all apps/games will be fast but at least the OS is on there. So you'll get most of the benefits i'd say. And one 80GB Intel SSD is pretty affordable IMO. Especially considering many here are having Core i7-class builds.
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October 15, 2009 10:01:12 PM

Yeah, I think a lot of us are like that. I have decided to buy 1st quarter 2010. I am going to go with the 4 SSDs for OS and all games. I think with 12gbs that the page issue is moot. If I run into issues due to no page file, I can always have it on the RAID0 setup. It will be better than my current setup.
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October 16, 2009 5:12:26 PM

One thing that hasn't surfaced in this thread - do Intel SSDs have the orphan file problem from excess rewrites to the drive or drives as other SSDs do?

Does the Intel controller manage this internally or would the drives need to be formated or cleaned with an external utility?

I wouldn't mind shelling out the bucks here on Intel drives. But Intel is often very vague on things such as this.

Anyone privy to this?
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a c 415 G Storage
October 16, 2009 5:55:06 PM

Intel has stated than a firmware update to support the TRIM command will be available for their "G2" SSDs when Windows 7 is released. That update, combined with the TRIM support in Windows 7, is supposed to mark deleted files as not having to be erased in the drive, thus avoiding write performance degradation over time.
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October 16, 2009 6:11:04 PM

sub mesa said:
Rather than using RAID to enhance performance of your SSD setup, why not go for a better SSD instead? Intel's X25-M G2 (with 34nm production chips) is by far the best consumer SSD right now, and it might be alot faster than two Crucial/Patriot/OCZ SSDs in RAID0 in many cases.


Um, I think you assertion is incorrect based on most benchmarks I have seen. The Intel drives are better in some cases and worse in others, they will not outperform two SSD"s using the Samsung or Indilinx controller (the margin is not high enough to support such a conclusion) TRIM if you go to 7. (OCZ Vertex does as does the Intel, likely msot drives will).
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a c 127 G Storage
October 16, 2009 6:24:40 PM

kamel: yes they will; however you probably look at MB/s only, which is an incorrect assertion regarding I/O performance. Sequential I/O is not the bottleneck and not why you buy an SSD. If all you know is MB/s and you don't know IOps; you don't know what I/O performance in modern systems is all about.

IOps is key. For sequential access you're talking about large data storage where performance is less important and HDDs already provide decent performance with 50-150MB/s throughput. But throughput is not the same thing as I/O performance.

The real reason why you want an SSD is to go from 100 IOps to 4.000 (write) - 30.000 (read) IOps as such is the case with Intel X25-M G2.
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October 16, 2009 6:36:46 PM

sminlal said:
Intel has stated than a firmware update to support the TRIM command will be available for their "G2" SSDs when Windows 7 is released. That update, combined with the TRIM support in Windows 7, is supposed to mark deleted files as not having to be erased in the drive, thus avoiding write performance degradation over time.


TRIM (SSD command)

Quote:
The TRIM command allows an operating system to tell a solid-state drive (or "SSD") which data blocks are no longer in use, such as those left by deleted files. An OS operation such as delete generally only means the data blocks involved are flagged as not in use. TRIM allows the OS to pass this information on down to the SSD controller, which otherwise would not know it could trash those blocks.

The purpose of the instruction is to maintain the speed of the SSD throughout its lifespan, avoiding the slowdown that early models encountered once all of the cells had been written to once.[1]

Although tools were already available to "reset" some drives to a fresh state, they also delete all data on the drive which makes it impractical to use as an optimization.

The root cause of the issue is that SSD drives do not know which blocks are truly in use and which are free. While the file system on the SSD will maintain an in-use list, SSDs don't understand file systems, and cannot access this list. This causes trouble in two places:

* SSDs can write 4KB blocks at a time, but, due to hardware limitations, they must delete larger blocks (e.g., 128KB - 512KB). Since the drive does not know which 4k blocks are still in use if they have been written to previously, each write will require a much larger read-erase-modify-write cycle, assuming that no additional free blocks are available on the SSD (i.e., after all blocks are at least partially filled). The term for this phenomenon is Write Amplification

* Wear leveling allows a drive to rearrange its data so the writes are not confined to one corner of the flash chip. Flash cells tolerate only a limited number of writes before they fail, so some SSDs will move data around to exercise all of the blocks in the drive more evenly. Since the drive does not know which blocks are truly in use by its file system, each block of data written to the drive requires an additional write due to the moved block.


So as this article explains, this is more of an operating system issue rather than the drive itself. The drive can only do what is commanded from the OS.

I've used programs to clean flagged files such as Revo Uninstaller - which has an erase feature to permanently delete deleted files and then defragment the drive. I also set the pagefile to clear upon shut down. Not sure if this would accomplish the same thing? But its something I've been vaguely aware of - deleted files not being truly deleted.

This may be a blessing in disguise to rid the drives of all that unseen and hidden data lurking around?
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a c 127 G Storage
October 16, 2009 7:44:33 PM

Quote:
The drive can only do what is commanded from the OS.

Not true. :) 
The drive can do what it wants, it just needs to remember how the OS thinks the drive is layed out. In reality, SSDs swap LBAs so what your OS thinks is the beginning of the drive, may be somewhere in the middle or at some random location. This doesn't happen in factory condition, but will happen as small writes are done, which are then written to a different place without the operating system knowing. The SSD then just remembers that the new place is actually supposed to be at the place where the Operating System had put them (the LBA numbers), it keeps a list to reference these, called HBAs.

You don't absolutely need TRIM if you create a smaller partition and keep some 20% capacity unused for the small writes. But with TRIM the disk would know which sectors are free because only the Operating System (well filesystem) knows that. So TRIM it just adding an 'interface' of information exchange between OS and SSD, with the SSD being able to gain from it but can also simply discard the command and do nothing.
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October 16, 2009 8:52:43 PM

sub mesa said:
Quote:
The drive can only do what is commanded from the OS.

Not true. :) 
The drive can do what it wants, it just needs to remember how the OS thinks the drive is layed out. In reality, SSDs swap LBAs so what your OS thinks is the beginning of the drive, may be somewhere in the middle or at some random location. This doesn't happen in factory condition, but will happen as small writes are done, which are then written to a different place without the operating system knowing. The SSD then just remembers that the new place is actually supposed to be at the place where the Operating System had put them (the LBA numbers), it keeps a list to reference these, called HBAs.

You don't absolutely need TRIM if you create a smaller partition and keep some 20% capacity unused for the small writes. But with TRIM the disk would know which sectors are free because only the Operating System (well filesystem) knows that. So TRIM it just adding an 'interface' of information exchange between OS and SSD, with the SSD being able to gain from it but can also simply discard the command and do nothing.


Ok cool, thanks for the information. SSDs are a whole other beast from their predecessor HHDs.

Can you clarify what you mean by "smaller writes" being written to another partition. I'm a big fan of well planned partitioning but have not heard of this scenario before. Or perhaps I have but have overlooked it due to it being a non-issue with most HHD based systems. Would this be in line with the pagefile or is this something different?

Thanks, I'm learning a lot about SSDs on these forums. Great place to get the heads up such things.
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a c 415 G Storage
October 16, 2009 9:43:46 PM

cloudNINE said:
So as this article explains, this is more of an operating system issue rather than the drive itself. The drive can only do what is commanded from the OS.
It takes two to tango. The OS has to issue the TRIM commands, and the drive has to be able to recognize and act on them.
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Anonymous
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November 19, 2009 4:05:02 PM

I have been doing the same thing with an older system windows xp with 4gb of ram and and 8gb solidstate drive. I was given the ssd and to be honest its to small to do anything else with so I got to playing. In XP there is not a button to click on to change the location of the pagefile, but you can edit a registry key and get the same results. Running pretty good at the moment.

Only thing I would like to add is why waste the money on a 64gb ssd for the pagefile. you wouldnt want to created a 64gb page file and that would be an awful lot of wasted space.

8 or 16gb would be much less of a waste.
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