Downsides of 2x 120GB non-raid vs 1x 240GB ??

Moi.

I am probably be getting a (Clevo P370EM) laptop with fixed configuration:
- single Intel 330 120GB SSD
- preinstalled Win8 (boo)
- I will need 120GB more SSD space

1. As a newb to the SSDs I would really appreciate if someone could point out the main differences of having 2x120GB vs 1x256GB.

Wondering if I should swap it to 256GB drive and do a reinstall or just buy a second 120GB SSD? All audio/video/photo is stored on a NAS storage so this laptop will have only OS/applications/games --> the intel 330 should perform fine enough for me. I suppose the 120GB would be more than enough for responsive OS & apps. Other disk could then serve as games storage.

Effective cost of swapping to 840pro ~= 145eur
Effective cost of adding Intel 330 120GB ~= 110eur
Effective cost of adding Intel 520 120GB ~= 130eur
(Effective cost of adding 840pro 128GB ~= 155eur)

2. How full can you fill up the 120GB drive without losing all its performance. What is the "effective" space on 2x120GB vs 1x256GB?

3. Any other downsides of having 2x120GB?

4. Performance difference of 840pro vs intel 330 as normal OS disk in real life?

Just wondering if swapping the SDD is really worth the work.

-sacro-

 

1) The main difference between the two options is that for the 2 SSDs, you have to pick/choose where files/programs/OS goes, whereas with one drive, that's it. Another possible issue is that you might lose more usable storage space with 2x120GB than 1x256GB, depending on what the final formatted capacities are + % of the drive(s) you leave free. Have you also considered buying a 256GB SSD and just moving the OEM-supplied 120GB SSD (assuming you buy that configuration) to the secondary HDD bay?

2) I typically keep my SSDs at lest 20% free (after formatting) to keep the performance of the drive. Though I'm expecting tiller to come by at any moment to suggest and even higher percentage

3) See 1

4) I have a 330 180GB and I'm pretty happy with the performance. Even wrote a review for it: Intel 330 Series SSD Review, Upgrading the ThinkPad W520. As for the 840 Pro, there should be a decent number of online reviews to read about it, including here on NBR.

 

1) Buying a 256GB SSD as main drive and moving 120GB OEM one the 2nd slot is not a option. I do not need this much space and would rather sell the 120GB drive then.

4) Thanks for link. I am more interested on the real life situations with 330 & OS. It is easier to ask opinions rather than finding concrete test numbers.

 

Your risk of losing data increases by a factor of two with RAID 0. Have an issue with one of the two drives and data is gone. Granted, have an issue with one drive in a one drive system your data is gone too but is usually more easily fixed or recoverable. Usually RAID 0 is a lot more sensitive to errors and corruption and the whole array will have to be rebuilt, which means a clean install.

Personally, unless you really need the added speed, of which will mainly be seen with lots of data transfers, it really won't matter. In any case I would still do a clean install regardless.

I have never overprovisioned a drive and never noticed any depreciable performance with regular tasks. Only if you do lots of data writes will it become apparent, and even then not so much. Heck I'm torture testing a Samsung 840 (not Pro) 120GB SSD right now with no OP and until it hit 100TB writes did the write performance even start to drop, and that is due to failing cells not due to no OP.

 

I don't think OP was ever planning on a RAID, but I definitely agree with you on the reasons why not to use one.

 

Yep, no RAID.

Just 2x120 vs 1x256 wondering...

-sacro-

 

Very high chance of the 1x256 having noticeably better performance than the smaller drives.

 

The way I see it, 2x120 non-RAID gives you more advantages than downsides, especially if you store everything on a NAS. Here's my breakdown (+ advantage, - disadvantage).

+ More reliability - the chances of you losing both drives are extremely small, one may fail but you'll have the second to work with while your RMA is processed;

+ More performance - using two 120GB SSDs is obviously faster, although you'd need to do something intensive to take full advantage of it. For example, having a virtual machine, games or cache/scratch disks on the second drive while your main OS and page file are on the first will be faster than with one 256GB drive;

- (Slightly) Harder to manage files (which go where - a bit of setup and thinking ahead will be required);

- Upgrading to a larger SSD in the future will require you to take out one of the 120GB drives (but you said you can sell it, so it's not a problem, plus more SSDs = better ).

As for space without losing performance, from what I learned, you can use 100 GB on the 120 drive while keeping near top performance. That's for Samsung's, but Intel's should be similar (or better since there's already 8GB over-provisioned from the factory).

Also, upgrading is not hard - HDClone the current drive to the new one and you're done...

 

Thanks for the detailed comments. Did not actually even think of cloning, so no need to actually reinstall Win8.

 

I have my doubts about the claim that 2x120 will perform better than 1x256. Typically, small SSDs have a performance hit since they fully don't take advantage if their controllers and whatnot, whereas bigger SSDs will. I don't have time rigt now to look up the stats for you, but a quick google search should show you.

 

256gb is a good spot for the samsung 840 pro (I think its the same for the ocz vertex 4) and 480gb is the one for the m500.

those 3 are the ones worth buying

and the difference in speed against 128gb to 256gb is usually felt

 

True, most drives perform better the larger they are - but 2 smaller drives should still outperform a large one. Say you run a game with highly compressed data files on the SSD - having it on the same SSD as the OS and page file will make it load slower than having it on a second separate SSD. The same for a virtual machine.
Just accessing two files at the exact same time will be (slightly) slower on one SSD, as well - we're talking ms though, so not really noticeable but still slower...

 

Samsung 840 Pro 128GB is actually close to performance of 256GB. But the standard 840 120GB is dismal (like 140MB/sec write) compared with 250GB (like 250MB/sec). I read too quickly originally thinking it was RAID but clearly it's using two 120GB or single 250GB. I all depends on your work load. I run a 256GB mSATA for my OS and apps and 512GB SATA for games, storage, and VM's. It's nice to store my drivers and stuff on there too, so I can periodically backup my documents data, wipe the 256GB drive and reinstall Windows and have my data zapped back onto my C: drive quickly.

 

jotm, have to disagree with you. A 'too small' SSD which is exactly what a 120/128GB capacity is... will never be as fast (sustained, over time) as a 240/256GB SSD that has it's nand channels fully populated and optimally interleaved - not even 2x, 3x or 4x 128GB SSD's...

If we're assuming the same % filled on each drive (no matter how many we have) and also the same % unallocated - then the SSD with the nand channels fully populated (usually 8 channels in today's SSD's) along with each channel fully/optimally interleaved (usually 4 chips per channel) will out perform the same controller with less nand - always.

This is exactly the reason that the new Crucial M500's are now only worth considering (performance-wise) at the 480GB and 960GB capacities - because with the jump to 128Gbit die - you need double the chips to fully populate the controller's channels and of course you get double the capacity.

Everything previous to the M500's is using 64Gbit die (max) - thus needing at least 32 nand chips (or more) to put the controller in a position to offer the best performance possible.

Even then; that is not guaranteed - but what is guaranteed is that the performance of the SSD will be as high as possible, will be higher than a HDD (even when the SSD is in a heavily used, or; steady state) and unlike the smaller SSD's - you have a chance to over provision (via the 'unallocated' method) to ensure that the performance stays consistently high while also giving a useable, real world capacity for your O/S, programs and some data.


Buying a 120/128GB SSD (pre M500) or a 240/256GB SSD (post M500) or smaller is like painting flames on your 4 cylinder car - sure it will look 'fast' - but the go parts are still firmly planted in moped (instead of drag race car) territory.


What is even worse than simply being 'not optimized' (re: controller channels vs. nand chips/dies) is the fact that Samsung's SSD's have a write latency that even a user would notice. The 256GB and larger capacity models do not suffer (as much) from this latency which effectively 'pauses' the user's experience while GC is taking place - in the foreground instead of the background as it's supposed to...


Although an SSD controller can be made to handle a wide variety of configurations - there is still one 'optimal' setup that is usually the one to go for. It's not like you're spending $2K more or anything like that - and it's not like you won't use the capacity either... But the performance difference is enough to keep using the SSD in the original (or future) system indefinitely vs. wondering why you spent 10x the $/GB $$$ to get similar to HDD performance in a few weeks/months.

And just because the 128GB 840 Pro is considered the best of the 'small' capacity SSD's - doesn't mean it runs with the 'real' SSD's either (sustained, over time - in real world workflows).

 

I will soon be able to refute that claim tiller. My 120GB Samsung 840 (non Pro) with no OP is showing ZERO write latency. I've been tracking time it takes from the copy call to end of write and there's been zero difference from day 1 0TB to 120TB writes so far, and with a drive dynamically ranging from 80% to 100% full. The write speeds have also not suffered one bit, although the odd thing is read speeds have diminished significantly.

 

Depends on what you doing with the additional space.
I would get a extra drive if it is for write heavy/scratch disk.
A 256 if just to hold software /game(read).

 

Made my decision and bought the 256gb 840pro.

I thought this would be simple question though still some nice discussion arose

Thanks for the comments.

-sacro-