tags:

views:

389

answers:

4

IDE,SCSI,SSD,SATA or all of those.

+1  A: 

How deep is the ocean?

(Memory is many orders of magnitude faster.)

Brian
For the record, I didn't downvote you.
OMG Ponies
I think you did
lubos hasko
There, I upvoted you, so now you're at zero heckavotes.
John Lockwood
Why does the StackOverflow audit trail show a down vote by rexem?
Alex
+5  A: 

Random Access Memory (RAM) takes nanoseconds to read from or write to, while hard drive (IDE, SCSI, SATA that I'm aware of) access speed is measured in milliseconds.

OMG Ponies
thank you, rexem.
lovespring
@lovesprin: You're welcome.
OMG Ponies
+1  A: 

Hecka-lot faster.*

[ Measured using the Hecka-lot scale. :) ]

John Lockwood
i c, thanks,john :)
lovespring
I use this scale on a day-to-day basis. It's really quite impressive, it can be used on distance, speed, weight, mass, volume, and even intangible concepts such as love and other emotions.
Carson Myers
thanks for the laymans translation
Joshua
+6  A: 

I'm surprised: Figure 3 in the middle of http://queue.acm.org/detail.cfm?id=1563874 says that memory is only about 6 times faster when you're doing sequential access (350 Mvalues/sec for memory compared with 58 Mvalues/sec for disk); but it's about 100,000 times faster when you're doing random access.

ChrisW
Which is one reason that Vista introduced ReadyBoost... even though sequential access on a flash drive is much slower than a hard drive, there are no mechanical, moving parts on the flash drive so random access is just as fast as sequential access.
Eric J.
The link I cited said their test was using a freshly-booted machine, to avoid measuring any O/S caching.
ChrisW
sounds about right!
Domenic
"on the flash drive random access is just as fast as sequential access" -- the link I cited says that it's 10,000 times slower.
ChrisW
Erhm, I don't know how they tested this exactly, but RAM access in my system is in excess of 26 GB/s, 19 times faster than mentioned here. Also, the tested disks are not exactly a typical setup, unless we're talking servers specifically.
Thorarin
http://www.tomshardware.com/picturestory/511-4-memory-scaling-ddr3.html says about 100 GB/sec for DDR3 memory. That ACM article was measuring on a server with 64 GB RAM (so I suppose possibly not the fastest/most expensive type of RAM).
ChrisW
I don't know about 100 GB/s... I have 1800 MHz DDR3 after all. Still, it's a huge difference. To be fair, my sequential disk access is slightly faster than these figures as well, but only by a small amount (270 MB/s or so)
Thorarin