Looking for an SSD.

[Agent]

I'd heard that SSDs don't like being over 50% capacity anyway

That is crazy talk.

[Ttaskmaster]

That is crazy talk.

Probably just a variant of "Set capacity 20GB lower than stated for avoidance of speed degradation as the drive fills up".
A lot of the reviews I read spoke of degradation occurring becoming noticible around the 50-75% range, depending on model.

Stuff like this:
"SSD's are made up of flash. Flash is made up of cells, which store 1-3 bits per cell depending on the type of flash. cells are arranged in pages which are the smallest writable area available. Pages are arranged into blocks, which are the smallest erasable area available.
SSD's can slow down long before they are completely full. They slow down when every block/page/cell of flash has been written to. At that point you run into a situation called a read/modify/write. This is when data needed to be written that is larger than the unused area available in a block. What has to happen then is the partial data is read out of all of the existing pages in a block. It then erases the block entirely. It then writes back the old data + the new data into the pages it needs in the block, leaving the rest marked as "unused." TRIM helps alleviate this by cleaning up blocks/pages/cells into this sorted out state a bit more proactively.
Most modern SSD's make good use of TRIM and garbage collection so they won't slow down past a certain point, and never slower than a traditional hdd, even when more or less entirely full.
With SSD's it's more or less how much data you turnover (write/delete), not how much you store".

[ik9000]

see this article: http://www.anandtech.com/show/6489/playing-with-op

and don't go crazy, basically on a 120GB setting capacity at 100GB should suffice.

[aidanjt]

I'd heard that SSDs don't like being over 50% capacity anyway

Folktales. Modern SSDs have excellent wear levelling and garbage collection software in the firmware.

[MrRockliffe]

I just got an SSD with my macbook pro retina, and although it's quick, I could definitely live without it. It's not noticeably faster, in the sense that chrome opens 5 times quicker etc. Programmes might open 30% faster at a push, boot up times are improved by 10 seconds, maybe 15, but when turning on my computer I prepare my desk for use anyway. I move all work out the way and set my keyboard and mouse up, which normally takes 15 seconds anyway, so it's honestly not really worth it for me. When they're 50 quid for 500gb, then I'll buy one.

[MrJim]

Folktales. Modern SSDs have excellent wear levelling and garbage collection software in the firmware.

I've read quite a few reviews whereby the speed of the SSD has reduced markedly once they're more than about 80% full. SSDs do vary quite a bit though as to how pronounced the slow-down can be; the Samsung 840 Pro known for this problem, whilst the Corsair Neutron suffers much less.

[ik9000]

see this article: http://www.anandtech.com/show/6489/playing-with-op

and don't go crazy, basically on a 120GB setting capacity at 100GB should suffice.

I've read quite a few reviews whereby the speed of the SSD has reduced markedly once they're more than about 80% full. SSDs do vary quite a bit though as to how pronounced the slow-down can be; the Samsung 840 Pro known for this problem, whilst the Corsair Neutron suffers much less.

as shown in the link I gave above.

And this is separate from wear levelling and TRIM functionality. The spheres overlap but are not the same thing.

http://www.anandtech.com/show/6489/playing-with-op
The first set of graphs shows the performance data over the entire 2000 second test period. In these charts you'll notice an early period of very high performance followed by a sharp dropoff. What you're seeing in that case is the drive alllocating new blocks from its spare area, then eventually using up all free blocks and having to perform a read-modify-write for all subsequent writes (write amplification goes up, performance goes down).

Corsair Neutron 0% OP


Samsung 840 Pro 0%OP



So with 0% OP sustained write performance over time is more erratic for the 840 pro than for the Neutron. However set aside some capacity as ring-fenced unused and things change:

Corsair Neutron 25% OP


Samsung 840 Pro 25% OP


Once you OP the drives a bit they become the same in terms of sustained write performance over time. The 840 Pro then wins with its superior speeds across the board in all benchmarks and tests.

And look at the zoomed in graphs which I won't link into here but are also on http://www.anandtech.com/show/6489/playing-with-op to see in more detail how the use of overprovisioning avoids write amplification problems and gives long-term steady state performance similar to day1 performance. Well worth it IMO to keep the drive running sweetly.

[Agent]

That article sets out to show the limitations of a SSD in specific situations.

Just think about what it's doing for a second: It's hammering the drive with 4k requests (32 depth for good measure) for 33 minutes after being filled to try and make sure the drives internal GC/TRIM can't kick in. Anand even say:

The goal was to simulate worst case IO consistency

To generate the data below I took a freshly secure erased SSD and filled it with sequential data. This ensures that all user accessible LBAs have data associated with them.

The tests are set to simulate a workload that is totally unrealistic for almost any home user. Seriously, this is in the realms of server based requests (with a bad system admin) - in which case, why the heck are you using a consumer drive?

In addition, the drop off only starts to happen consistently after say 200-ish seconds? So that's still 3 and a half minutes of this before it falls...and even then we're still seeing almost exclusively (minus a few blips) above 1000 IOPS. A 7.2K RPM drive is normally under 100 IOPS, so you're still talking ten times more IOPS in this crazy scenario.

Sure, filling a SSD is going to give you a performance hit - but look at the situation that it takes for this to even be an 'issue'. This article is more of a poster for why you should just plug in your SSD, format it and use it like a normal HDD, keeping in mind that a few % free on it will help. All this OP stuff for situations that are unlikely to ever happen is barmy.

[ik9000]

That article sets out to show the limitations of a SSD in specific situations.

Just think about what it's doing for a second: It's hammering the drive with 4k requests (32 depth for good measure) for 33 minutes after being filled to try and make sure the drives internal GC/TRIM can't kick in. Anand even say:





The tests are set to simulate a workload that is totally unrealistic for almost any home user. Seriously, this is in the realms of server based requests (with a bad system admin) - in which case, why the heck are you using a consumer drive?

In addition, the drop off only starts to happen consistently after say 200-ish seconds? So that's still 3 and a half minutes of this before it falls...and even then we're still seeing almost exclusively (minus a few blips) above 1000 IOPS. A 7.2K RPM drive is normally under 100 IOPS, so you're still talking ten times more IOPS in this crazy scenario.

Sure, filling a SSD is going to give you a performance hit - but look at the situation that it takes for this to even be an 'issue'. This article is more of a poster for why you should just plug in your SSD, format it and use it like a normal HDD, keeping in mind that a few % free on it will help. All this OP stuff for situations that are unlikely to ever happen is barmy.

Which is exactly why I suggest not going mad and not using 25% OP which the article nudges you toward but do suggest setting some space aside to help. I went for 15% IIRC. Having filled my smaller SSD 95% and seeing it degrade markedly in speed I think there is merit in leaving a bigger margin of unused space. The article explains why, technically this happens, and with worst case usage being just that I know my drive will run sweeet for the time to come.

[ma9mwah2]

I decided after my OCZ 60gb just dying on me to get a 128gb-corsair-force. seems to be a good balance between price and speed

[liammcd]

Seagate 600 Series 480GB 2.5inch SATA-III SSD is currently going for £160 as a daily deal.

Sounds a bargain to me, but I don't need one right now.

[sct454]

Oh, I forgot to keep you guys updated. I ended up going with the Corsair Force GS 128GB SSD. It was on Scan's today only deals for £55. So far I'm loving it.

[Agent]

Not sure why you'd go with that over a M500/840, but if you're happy

This stands true for any drive really, but make sure you keep backups. If a Sandforce drive dies, they really do *die*.

[Frankenfurter]

I have a Kingston SSD Now 300 120GB and it cost like, £45 in one of the sales that are on allll the time online.

Might not be the most reliable or fastest, but given that the speed difference is barely noticeable between SSDs anymore and that you can get two of the blighters for your budget (or 3 if you really wanted) and run them with redundancy, seems a pretty good shout to me to save a couple of bucks.

Anyway, mine has done me very well so far.

edit: Oh sorry - I didn't realise there was a second page and just replied to the last post on page 1. Duuh >.<
Can't find a delete button but if the mods wouldn't mind... sorry! >.<

[nniitt]

Not sure why you'd go with that over a M500/840, but if you're happy

This stands true for any drive really, but make sure you keep backups. If a Sandforce drive dies, they really do *die*.

It's so hard to suggest a SSD, Go for intel 730, mate! Nobody mentioned 730 so far, right?