HDD vs SSD vs RAM

Recently I wanted a machine that would be added to a cluster that does some heavy lifting with Wikipedia. CPU consumption is not much, but the I/O bandwidth is pretty much peaked out in all our cluster nodes.

All our cluster nodes have large amounts of RAM, in excess of 8GB, although now it does not sound like much. About 6 GB of this RAM is converted into RAM disks using freely available software like, Dataram RAMDisk.

HDD and SSD comparison are available all over the internet and I just used this as reference. The results of these test can be summarized as follows:

Disk Drive	Avg Read rate (MB/Sec)	Avg Write rate (MB/Sec)
HDD	98	87
SSD	196	85

Now I thought that was very impressive for SSD's compared to HDD. But RAM is so much faster and if you can fit all your disk intensive data onto the RAM, then you wont need a fast HDD or SSD or RAID 0 SSD, etc.

Here are the results of the benchmark that ran on the RAM disk.

Disk Drive	Avg Read rate (MB/Sec)	Avg Write rate (MB/Sec)
RAM disk	787	785

Now that is fast. I have decided not to buy any SSD's as all my data can fit into RAM itself. I hope this article can help others decide on expensive SSD's and even RAID 0 with SSD's.

But one thing that I have to mention here is that you can have the OS run on an SSD, but not the RAM disk setup that I have mentioned here. So if you want speed boost prior to the OS boot, then try out an SSD. Personally I feel they are still not worth the buck, unless you use it in a RAID.

Remember, if your data fits in the RAM, then you can see blazing speeds. If a Photoshop user reads this, then they can definitely try it on a RAM disk or RAM+SSD. I will be doing this for my Dad(professional photographer) sometime soon.