My next Workstation

Ken kmmos1 at verizon.net
Sat Jul 10 16:16:55 UTC 2010


On Thursday 08 July 2010 10:11:15 Billie Walsh wrote:

<[snip]>

> In my experience with computers memory is always going to be faster than
> mechanical hard drives.

Yes, pretty much by definition. The average access time of a rotating hard 
drive is on the order of magnitude of milliseconds, and the average access 
time of RAM is on the order of magnitude of nanoseconds. The difference is 
six orders of magnitude, or, stated another way, RAM is a million times 
faster than hard drives.

> Back in the dark ages I had an old 8088 computer that I installed what was  
> called a "Rampat" board with 100meg of memory on it.

Really? I don't remember those 16-bit ISA cards holding more than 16 MB of RAM 
on them. Were memory boards marketed to the general public in those days of 
640 KB MS-DOS addressability capable of recognizing 100 MB of RAM? Remember, 
we're writing about rows of discrete, spidery-legged DIP chips, not today's 
snap-in memory modules.  And back then, what would a 100 MB board, if it had 
existed, have cost?

<[snip]>

> Something else. Never skimp on memory. Use as much as possible or until
> your dipping into the kids college fund, whichever comes first. Best
> investment in computer performance.

Thanks for the Saturday morning laugh. Yes, RAM is the best performance 
investment for PCs, but there are a couple of considerations. One is that RAM 
prices are relative to their time. I can remember buying a new Pentium 
machine to run the then brand-new Windows 95 when RAM prices were $40 per 
megabyte, and 64 MB of EDO RAM would cut into the kid's college fund -- or 
mine, for that matter. Today's memory prices, per megabyte, are two orders of 
magnitude lower than fifteen years ago, and really are a performance bargain.

(I was too young to participate, but I've heard a 1960's era IBM mainframe RAM 
upgrade of 32 kilobytes was about a quarter of a million dollars.)

The second consideration is a physical one. If one installs multiple gigabytes 
of unused RAM, the machine still takes time to manage all of the installed 
RAM all of the time, as opposed to just accessing hard drive memory locations 
when specific locations are needed. Even though RAM is a million times faster 
than rotating platters, it still takes machine time even to manage RAM the 
operating system and applications are not using. The result may be measurable 
performance lags, not to mention power usage and heat generation, from system 
boards over-packed with RAM that is not actually needed.


Ken




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