Sunday, July 8, 2012

SSDs and what they bring from the table

These days if you go to a reputed computer hardware dealer in S.P.Road, Bangalore and ask either for an enterprise drive (64 MB cache, SATA III, 7200 RPM) or a 10000 RPM Velociraptor, they will almost frown at your request and immediately ask you that why you don't go for an SSD ? 

As their were confusing choices in the HDD area ( I like 3.5" drives from Western Digital, as they haven't died on me, some even after 6 years), there are in SSD. WD itself has Caviar greens, blues and blacks, apart from Velociraptor and Enterprise.In SSDs there are tons of choices from OCZ, Corsair, Crucial, Intel, Samsung, etc. To begin with let me make some recommendation of WD HDDs

(1) Caviar Green -- Very good drive for NAS, where you network connection and processor will be the bottleneck and not the transfer speeds of the drive. They run cooler and make less noise
(2) Caviar Blue -- Your regular Computer user.
(3) Caviar Black -- Power user who needs a fast drive for reads, not so much for writes and does not care too much about reliability
(4) RE4 enterprise -- RAID, most reliable and for servers or users who do a lot of disk writes (uploading/downloading torrents for eg.). I recommend this sa workstation drive too, though WD does not list it that way.
(5) Velociraptor -- At the low capacity end (250 GB) I do not recommend it, as its pricey, does not offer enough storage and you should seriously look at SSD as your boot drive + applications and mate with one of the above 4 for data. the SSD wil be much much faster as a boot drive.

Coming back to the core topic, lets see what per common choices that will influence a buyer's decision

(1) Cost -> One metric is cost per GB. Even with falling SSD prices and inflated HDD prices due to flooding in Thailand's HDD manufacturing units, SSD do not fare well in this metric compared to HDD. Except of-course the 250 GB 10000 RPM raptor drives. If some one has an idea of using a raptor as a boot drive, drop that idea right away and look at SSD for that and supplement it with an additional HDD for data. In simple words, SSD make no sense for storage.
(2) Performance --> SSDs are miles ahead of HDDs (even the WD velociraptor) in performance (read/write). They have bigger caches ( I have 1 GB cache in my OCZ Vertex 4 compared to 64 MB in WD RE4). My windows & ultimate installation with tons of Apps and un-optimized services at start-up boots in 15-20 seconds flat after BIOS loads the MBR (would give it a minute in HDD). Apps start in a zap (like office, photoshop, Corel, etc) 
(2) Noise -> SSDs are flash based and have no mechanical parts. Therefore they are silent while even the best HDDS are fairly audible., the blacks, enterprises and raptors being much more louder.
(4) Durability -> A not so important concern for desktops, but the crown will go to SSDs. We don't throw Desktops around, do we ?
(5) Reliability -> This is where things get tricky. SSDs have a technology limitation, that the number of writes on any sector (if we compare it with an HDD terminology) is limited. In simple words we can say that the same area on SSD can be written only a finite number of times (it is almost infinite in case of HDDs). Manufacturers are very picky about this and DO NOT mention this *finite* number in their product specifications and instead talk about performance only. So in general SSDs can seem to be less reliable than HDDS are not suitable for applications, features which constantly have a very high number of writes during their usage lifetime. And that's why we do not recommend SSDs to be used for data. I will cover this point in detail in a subsequent post as to how to manage this to extend SSD reliability and get the performance and reduced noise benefits.
(6) Power Consumption -> SSDs win here too by a wide margin, however their cost per GB limits limits their usage in Media Players and NAS. I would have recommended this for car audio, but pen-drives are cheaper and have lesser footprint for this applications 

So for now, the best combination is 
(a) SSD for OS + Applications --> The OS and application have to be tuned to work best on SSDs
(b) HDD for data --> Your multimedia files, Development projects, Email databases, browser caches, torrent data and temporary files, etc ...

I will shortly post in detail on how to do this for Windows 7 and linux later.

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