Raid vs raptor - Page 2

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I just built a PC a month ago with 2 WD Raptor 10,000 RPM 150 GB drives and placed them in a RAID 0 configuration using an onboard Nvidia Controller on an ASUS A8N32 SLI motherboard.

I also have a WD 400 KD hard drive. I use the 400 GB drive for storage & backups, and the RAID 0 array (300 GB total) for Windows & games.

For the nay-sayers (read: RAID non-conformists), after using RAID for over a month now, I can wholeheartedly agree that RAID offers advantages in speed and latency over a single drive. If you play games, RAID is highly recommended! If you play Battlefield 2, you know what I mean when I say that load times are not a deal breaker, but are damn annoying when you want to get into a game. Don't mind waiting 60+ seconds for the game to load? You're more patient than I am.

Frankly, I can't think of a reason NOT to have RAID if you are a gamer. As long as you back up critical data, you are 100% safe if hardware crashes. You see, other components can fail too...which is another reason to back up your data. I had lightning strike my computer, so I learned that lesson...but I digress.

If you want to see actual numbers, read Maximum PC. Every month it seems, they do benchmarks on all kinds of hard drives both with and without RAID, using HD Tach and other benchmarks.

I will echo the sentiment that cost is NOT the factor for hardcore gamers like myself. We have to have the best, cost be damned. If there was room in my PC to do a SCSI RAID 0, trust me, I'd do it!

The fact is the slower rpm drive has in theory, built with the same tech, a longer life due to less heat and wear on the spindal. True the raptor has a longer warranty but more due to higher price tag. I have a 5400rpm western digital working for some 10 years now. When combined with software SSD the life of any drive will greatly increase as it acts as a much larger cache greatly decreasing number of hits to the primary drive.
Software SSD is near the fastest SSD doing about 80X that of any hard drive and the software only costs is $49.
http://www.cenatek.com/store/morei [...] N=11155387
Iram is a good SSD but only about 6X that of any hard drive but it can hold 2x, with 1 iram or 4x with 2 iram cards, of the current motherboard based software SSD. Iram's best parts is battery backup and can boot your OS for around $100 plus the RAM. Will make a great use of your old DDR once you move to DDR2 memory.
http://techreport.com/reviews/2006 [...] dex.x?pg=1
I use the 7200rpm drive and software SSD due to an equal price point to 2x 74Gb raptor raid. While a raptor primary drive would be some faster with a software SSD I would say the SSD is far more important in the build for a gamming system.

silverfrog why did you submit it twice? Raids nice but for gamming software SSD should come before the second drive.[/quote]

True but in this case were talking about a 2 to 3Gb software SSD than can hold mostly all of any game. The software drivers for the SSD wouldn't even take the time to check the HD but stop at the RAM where the software SSD has the files.

In most games thats the case but a few will come with more that 3Gb's which the fact of RAM being 80X times faster than a HD will only slow it to say 75X the fastest HD.

Yes, I would could have guessed you misunderstood. The software SSD, works off system RAM and, cannot replace the HDD and requires a primare HDD.

RAM, the type I use anyway, has a lifetime warranty and should last 12 times longer than hard drives. True, it just have 1 HDD but after boot for any give game the hard drives job is done and the SDD take over saving the hard drive from all the massive loads of the different boards. The big difference is the SDD is 80X times faster than a raptor which cuts the boards load time, from 20+ second with HDD's, to only about 1 second.

Sure you can when it extends the life of your boot drive. IRAM is different its a memory card with battery backup which can boot and connects via SATA buts much slower than a software SSD setup on system RAM.

Preloading the levels is infact what you should preload as most of the game engine code an such is already going to be in normal system RAM. True, what you dont preload must be retrieve from the HDD but the part preloaded moves at 80X will make the entire game faster than any drive raid.

SSD is Solid State Disk and is the correctly define the RAM drive. SSD's or all volatile and the only real requirement is its made of RAM. The ones with batterys are simply bootable SSD's and if they loss power they too loss there data just like system RAM.

But those drives have batteries and external PSUs, whereas a software solution can't provide that kind of extra protection.

Again we need to think about pricing here, $2/gb for a Raptor is a LOT of money (when you can get in the UK a 250gb drive @ £0.24/gb). Solid State memory is even more - £50/gb is not really a reasonable price to pay.

As for saying 8mb of hard disk cache is faster than 16mb?

Hey, I've got an old 40mb drive with about 64k disk cache, it's rocketship fast.

So true but its also near the fastest and is the cheapest.

Yet you'll be upgrading your memory on the 939 mobo. Lets face it the DDR400 1Gb memory are about as low a price as they ever will be.

Wasn't I that said it but someone did say 8mb took less time to search than say 512mb.

Its true due to its less cache to search but searching 512mb of cache is faster than searching an HD.

When the SSD doesn't boot then it will go down the line which should be your HD. You then see nothing on your SSD and say crap i'll have to buy a new batter. The SSD should only hold a copy of whats on your HD. The software for the SSD should by default only copy the data. For bootable SSD's they update by defualt on a schedule. If a bootable SSD software should note any changes in it and the HD at boot, say from a power loss, and will correct it at that time. For the software SSD I suggest you should never place a database for say counter strike's WC3 mode, save games, or rankings of any kind to it.

SSD's may not at this point be for average users but neither are raids.

The software SSD I'm suggesting uses The systems RAM. After say programs use to much of the systems RAM to make a software SSD then you could just use the extra, RAM you install for the SSD, for just system RAM. Todays Games want use all of a fully loaded 939 mobos maxed out RAM. Use the rest over what the games use as a SSD and you'll only be out the cost of the software, which is $49, to set it up.

I agree 1 raptor is the best and a software SSD which would show a tangable data access improvement.

OK, everyone, Elbert is talking about a RAM Disk. Its not a SSD like iRAM, its not really a SSD at all. Its a RAM Disk. Its kind of preselecting what you want to be in system RAM.

@ silverfrog,
No, I'm not talking about searching 512MB on a HDD platter either... Besides, you don't search on a HDD platter - you know the address where it is, so you just drive there. Its a big picture of performance. There is a point where too much cache is more costly than than less cache.

Say the CPU requests data. First the system checks system RAM for it, right? (I assume the CPU wouldn't request data if it was in the CPU's caches). Secondly, if it doesn't find it in system RAM, it asks for it from the HDD.
So first, the HDD searches its cache for the data, right? That's why the cache is there. But if it doesn't find the data, you've lost time searching the cache when you could have been retrieving data.
So:
(average time to get data) = (% of cache hits)*(time to access cache) + (% of cache misses)*(time to retrieve data from disk)

So when the cache does not contain the data, you lose (% of cache hits)*(time to access cache) amount of time. The bigger the cache, the bigger the (time to access cache) is. Once the (time to access cache) = (time to retrieve data from disk), what's the point of having cache? So there is some point where having too much cache is detrimental to performance. Do you see my point?

Its more applicable in the CPU cache/memory subsystems than the HDD, but in principle its similar. Ask why don't we have a 2GB L3 cache? Because to search that 2GB of L3 cache is probably more costly than just going to the system RAM to get the data.

Why don't you think they can have more than 16MB of cache on a HDD now? I'm sure they could throw on 128MB w/o any problems... Perhaps the law of diminishing returns? And if they're just "holding out" on everyone, why aren't 32MB+ caches popping up in mainstream HDDs?

Its practically for all intents and purposes a RAM Disk. You preload it w/ whatever you want. Its using the system RAM... It might not fit the exact description of a RAM Disk, but its pretty much doing the same thing.

I know your not and I said its true that searching 16mb of cache is faster than 512mb cache but its faster to search 512mb of cache than 16mb of cache plus 496mb or hard drive space. Searching cache is timed in the nanosecond and searching HD's are timed in the millisecond thus cache is searched faster.

Again, you do not search HDDs... The head moves to the address given by the master table and you just read from there. I said it before, I'm saying it again. HDD's are done in ms because that is the seek time. Seek time is not search time. Your HDD does 1 seek to drive to a point on the HDD that contains the data. Thats it. It doesn't search the entire drive for your data.

More cost but not quicker. Cache on the CPU has faster access time than RAM but its a trade of the more cache the less room for other parts of the CPU like ALU. 2Gb of cache would take up alot of the CPU.

That was a rhetorical question... Besides, they can make the CPU as big as they want. (yeah yeah, yields, etc etc, i know.) I was using some exaggeration to make a point. I was giving an example to show my point.

Your correct in they can have more cache than 16Mb but the band width of the SATA limits its worth. The Iram uses the SATA and its the slowest being only about 6 times faster while software SSD is 80 times faster than any HD. The more cache the greater the cost of the HD, really the only thing hard drives have over SSD's is price, thus increasing the worth of SSD's and sales as you add cache.
Why does SATA bandwidth limit its worth? Since SATA has versions from 150MB/s to 300MB/s, the burst from the cache could be greater than it is now. Please explain how you got that?

Cost? We're talking about going from 16MB to 32MB of cache... Sure, I can see the cost going up if it was like 512MB or 1GB, but an extra 16MB?? Maybe an extra 20 bucks?
Here's 2 seagates. One's 8MB $94 and the other 16MB $114. $20 difference. Assuming linearity, people will pay an extra $40 if you say it has 32MB of cache.

http://www.newegg.com/Product/Prod [...] 6822154413
http://www.newegg.com/Product/Prod [...] 6822154414

Good posts overall! I hope I'm making a good point.. or two.

Actually, there is a reason why manufacturers don't include more cache into devices. That reason is cost. 2 GB is L3 cache would be out of everyone's price range. DDR3 RAM or faster is what video card memory is made of and look how much it costs for an extra 256 MB. Hundreds of dollars difference. And, that is cheap compared to cache memory!

L3 Cache memory for a processor is very expensive to add in large quantities. It has nothing to do with diminishing returns. Same goes for Hard drive cache memory. To go from 16 MB to 32 MB is more costly than you think. Like I said, CACHE memory is not your standard DDR400 Ram that you can pick up for $100 for 1 GB sticks.

Secondly, the time it takes to "search" RAM is infinitesimally small compared to how long it takes to access a hard drive platter. The seek time is about 3-5 ms on a hard drive and that's just to find the data, right? Then you have to transfer the data from the disc to cache and finally to system memory. 3-5 millisecond seek time combined with a throughput of roughly 70 MB/sec is incredibly slow compared to the access rate of cache memory, which operates at 400 Mhz+, giving you a speed of 1-2 Gigabytes per second! That is a huge difference. Thus, the whole process goes quicker the more cache memory you have.

Bottom line is:

There are no diminishing returns with cache memory made for hard drives, just like there are no diminshing returns by having more system memory. Memory has address locations which the processor can directly access. There is no "searching". The data is accessed directly and then transferred directly to it's destination, usually to the processor.

The "best" solution is dependent on your perspective. 1 WD Raptor is not the "best" for everyone. People like me who do not CARE about data loss regard 2 or more hard drives in a RAID array as "best". Or, better yet, a solid state hard drive, such as the PCI express RAM card with battery backup. To me, that is "best" because speed is all I care about.

My point was that there is a point where more cache is worse than less cache.

As for the 2GB L2/L3 cache, it was an example to exaggerate my point. I tried to explain that in my previous post. My diminishing returns question was about HDD caches, not L2/L3's...

Yes, I know its more expensive. I know its not system RAM, just like you said. Therefore you cannot compare them like you did:

You must search your cache. Things change in the cache, therefore you either have to have a LUT (look up table) for what is in the cache, or you must search the cache for the data that is requested. Either way is a search. If you want address X, you must search the cache to see if X is there. There is no way to magically know that X is there or not. This is done in hardware so its super fast.
So there are diminishing returns, but only after and beyond you reach a certain cache size.

I know for a HDD it'd take alot of cache to finally bring it to a point where the cache is detrimental to the system. This is what I think you're driving at, and you are correct.

We've kind of highjacked the thread, sorry to the OP.
BTW, I agree w/

Too that point your wrong. The more you have the less you have to depend on a slower media.

Im wanting a 2GB cache L2 or L3 makes no differnce to me.

The cache can hold the LUT and much more. The larger the cache size is faster HD and the only diminishing return is on the cost of the HD. The price goes up as the 74Gb raptor shows us and the performance goes up as well due in part to its larger cache.

No, if you can have more cache your HD will just become all cache or SSD if it cache could ever get that large.

True but with 496mb less cache you have to get all that extra data from the HD.

Yes they can but no one could buy it the price would be so high. Your point is wrong for as you step up to faster data storing device, be it a HD the lowest, RAM, or cache the fastest, its always better to have more of the faster storage device.

As you get more and more cache to come closer to the max possible band width. Iram is a perfect example it holds 4Gb's and so how long does it take the Iram to push all 4Gb's throw SATA? System RAM can do it in less than a second and thus my suggest is much faster than IRAM's and a RAID.

PCI-express would solve the problem but the reason they dont use it or even the PCI bus the card's pluged into is patent rights. Licensing the rights to run SSD on any PCI, AGP, or PCI Express slot would be high. There is a a SSD PCI card but its cost is high heres the link.
http://www.cenatek.com/product_rocketdrive.cfm

$1600 for a 2Gb SSD is highway robbery.

IRAM is comming with a better solution a SATAII, 300Mb per second, 8Gb SSD but I'm not sure if how much faster than the old IRAM it will be. It could reach 20X speed and may be the best consumer solution. I would want a Drive of system memory due to speed anyway with upwards of 80X that of a HD for my games.