New SSD confusion!

Fightsback

OGR,

your avatar is a dead ringer for Richard Stallman



[IMG]https://encrypted-tbn2.gstatic.com/images?q=tbn<img src=http://static.moneysavingexpert.com/images/forum_smilies/angel-smiley-002.gif border=0 alt= title=You are wonderful smilieid=16 class=inlineimg>Nd9GcQlMqHUsK0r42Nz9XR3WypKecu6rxMexmZ5Yt0l3blOcapfcJHM[/IMG]

londonTiger

OGR wrote: »

OK I'm gonna explain this quick as I'm on my phone and its not great for long explainations.

SATA has a maximum throuput of 6Gb/s, this ends up around 560MB/sec as SATA has more overheads than PCI-E. SSDs already satursate this and get held back.

One lane of PCI-E has a throughout of 8Gb/s, a single lane can hit nearly 1000MB/s. You can throw 2 or 4 lanes at a PCI-E ssd and so a 2x SSD will have 16Gb/s at its disposal. PCI-E SSDs off the top for my head are easily hitting 1300-1500 MB/s and thats on new NVMe tech which is yet to mature.

SATA is dead and isn't going to be developed any more. AHCI + SATA = old, PCI-E(M.2) + NVMe = the future. As time goes by more and more devices will move to PCI-E or M.2, especially because of space saving on small form factors.

What coulld the average home user possible need more than 560MBps for? The whole OS probably only takes up 3GB and sata3 could get load all OS files into RAM in under 6 seconds. That is still pretty shockingly fast.

It's not all about speed, it's about accesibility and how widely adopted a standard is. Sata is cheap to make and easy to work witth. Mobo can have 8-10 sata interfaces (plus couple of external ones). Mobs can add additional sata capacity by installing a PCIE expansion card.

PCIE slots on motoherboards are restricted, they take up a lot more room and are fat. Above all the speeds just aren't needed for home computing. In video editing for a television studio working with a 60GB video footage? yes.. home computing? No.

Lets not geek out about these things, I see it on the overclocking forums guys doing benchmark tests on their SSD drives and comparing performance. Oh x drive is better because it has 2% more read write operations per second. Big deal, in the real world it doesn't matter.

esuhl

Fightsback wrote: »

Ew, that's messy. I prefer to keep 'nix and windows on separate drives as windows has a nasty habit of doing evil things to grub or whatever other boot loader you use.

It's not that bad when you get your head round it. When I installed Windows 7, I set the PC to boot from a data drive so that the MBR on the OS disk wasn't overwritten. Once installed, I changed the boot settings back, so it was just a case of chainloading the Windows 7 boot manager in GRUB.

I overwrote the MBR once, but it was easy enough to restore by booting from the Live/installation CD, chrooting into the Linux installation, and then setting up GRUB again.

Fightsback wrote: »

Oh PS if not already aware, you'll need to sort the UUIDs when you clone the linux partitions.

Ahhh... what do I need to do to sort out? With GRUB Legacy I used partition labels, but I think (new) GRUB refers to UUIDs again... I'm not really familiar with that side of things.. :-/

londonTiger wrote: »

it would be more cost effective to put 2 sata drives in RAID striped than buy a PCIE ssd.

What kind of RAID implementation? Last time I tried to use a fakeraid implementation I found that dmraid wouldn't support the controller, so I was unable to boot into Linux. Maybe there's better support now?

Alternatively, if I use mdadm to create a software implementation of RAID, presumably I wouldn't be able to put Windows or OS-independent partitions on the same drive...?

To be honest, RAID has always seemed a massive pain in the (bottle)neck on home PCs that don't have proper hardware RAID controllers!

londonTiger wrote: »

It would be overkill to get a PCIE SSD just for boot speed.

I'm not desperately concerned with boot speed. It's more the speed and responsiveness of the system that I'm concerned with. I'll be getting an extra 6GB RAM too.

OGR wrote: »

I didn't see it mentioned here in a quick scan but if you go the PCI-E route you have to make sure it is AHCI and not NVMe if you are planning to keep those legacy OS. Only windows 8.1 and Windows 10 have NVMe support. I did see you asked the question about whether you could use PCI-E due to AHCI, you can get AHCI PCI-E based SSDs.

Ah... So I'd need an AHCI PCIe card to maintain compatibility. Thanks for the tip! That's the kind of thing I need to know!

Something like this is looking good, although it is a bit expensive:
http://www.scan.co.uk/products/240gb-kingston-hyperx-predator-m2-aic-ssd-hhhl-pcie-20-%28x4%29-read-1400mb-s-write-600mb-s-160k-119k-io

londonTiger wrote: »

What coulld the average home user possible need more than 560MBps for? The whole OS probably only takes up 3GB and sata3 could get load all OS files into RAM in under 6 seconds. That is still pretty shockingly fast.

Well, I'm not an average home user! And I don't have a SATA3 controller on my PC, anyway.

londonTiger wrote: »

It's not all about speed, it's about accesibility and how widely adopted a standard is. Sata is cheap to make and easy to work witth. Mobo can have 8-10 sata interfaces (plus couple of external ones). Mobs can add additional sata capacity by installing a PCIE expansion card.

PCIE slots on motoherboards are restricted, they take up a lot more room and are fat.

I only have four SATA ports on my PC and all are used, in addition to the two IDE ports. On the other hand, I have a capacious BTX case with plenty of room for another PCIe x4 or x16 card.

So, for me, using a PCIe port would be a distinct advantage over SATA, all other things being equal.

Robisere wrote: »

Try this with your current board:
http://www.sandisk.co.uk/products/ssd/sata/readycache/

Available from Amazon, not nearly as expensive as what you are considering. It is a cache drive, basically that means it learns to hold information every time you boot and after a few boots, it gets quicker and quicker. This will give you the faster boot you need until you can afford a new system. And after all, why spend more of the money now, when you can save for something totally better, with a more modern, faster board, later? That will have USB 3.1, faster memory, processor, etc. Get the boot speed you want now, at less cost.

Interesting... although it's not the boot speed that I care about.

It's not that I can't afford a new system yet; I just don't think it would be cost-effective upgrade when the PC still performs really well. It may be 6 years old, but it's still a really fast machine.

But anyway, I was also hoping to free up a bit of disk space by getting a ~300GB SSD... If I got a 32GB caching drive I'd also have to get a mechanical drive for extra storage... Hmmm...

Thanks everyone -- lots to think about! :T

Cycrow

[QUOTE=londonTiger;68882280
PCIE slots on motoherboards are restricted, they take up a lot more room and are fat. Above all the speeds just aren't needed for home computing. In video editing for a television studio working with a 60GB video footage? yes.. home computing? No.
[/QUOTE]

You dont actually need PCIE slots for PCIE SSD's. The slots are just one way to access them. Thats where M.2 comes in. These slots are much smaller, and the M.2 ssd's are much smaller as well.

the main limit on PCI-E is not the number of slots, but the number of lanes available. And these are increasing with every generation

poppellerant

Some conflicting advice in this thread which I can't force myself to agree with.

The main reason SSD drives are faster than harddrives is because their access time is close to zero. The access time is how quickly the drive can access a file.

Imagine a record player and that's pretty much how harddrives find their data - by moving the arm to the correct location and waiting for the data to arrive on the moving disc. This all takes time. With an SSD drive, there are no moving parts at all. The data is there as fast as the controller can electronically locate and transfer it.

I don't quite agree that cheap SSD drives will give you a blazing fast PC. These cheap drives often come with a gotcha - in my own experience with cheaper drives on different machines, it tends to be conflicts with the chipset. Sometimes this can be worked aroiund with different or updated drivers - but not always. I've also found that the cheaper drives don't have as many write cycles than say a drive which is £10-20 more, so bear this in mind while looking around.

If I was buying an SSD drive today, it'd be a Samsung 850 Pro if I could afford one. Obviously these come with a steep price tag, but with good reason - reliability. But to be honest, I'd be almost as happy with a Samsung 850 Evo drive. Just remember that the Pro can be written to many more times than the Evo.

Fightsback

poppellerant wrote: »

If I was buying an SSD drive today, it'd be a Samsung 850 Pro if I could afford one. Obviously these come with a steep price tag, but with good reason - reliability. But to be honest, I'd be almost as happy with a Samsung 850 Evo drive. Just remember that the Pro can be written to many more times than the Evo.

SSD's in general are more durable and reliable than HDDs, you want to see the reliability rate of Seagate's 3TB offerings, quite shocking and shades of the old IBM deskstar GXP models.

http://techreport.com/news/27697/latest-backblaze-reliability-data-shows-carnage-for-3tb-seagate-drives

Fightsback

esuhl wrote: »

Ahhh... what do I need to do to sort out? With GRUB Legacy I used partition labels, but I think (new) GRUB refers to UUIDs again... I'm not really familiar with that side of things.. :-/

Esuhl,

Here's an arch wiki

https://wiki.archlinux.org/index.php/Disk_cloning