Questions about DDR RAM

External Since: Oct 03, 2007 Posts: 12

Somewhere on the interweb "Igor" typed:
> On Tue, 02 Oct 2007 20:32:30 -0400, CBFalconer <cbfalconer.DeleteThis@yahoo.com>
> wrote:
>
> <snip>
>
> > But, if the MB can handle it, ensure you get ECC capable memory.
> >
>
> My motherboard's manual doesn't say anything about supporting ECC, so
> I'll assume that it doesn't.
>
> However, I plan on putting together a PC from scratch in the near
> future, so perhaps ECC support is something I should be looking for
> in a motherboard.
>
> In a nutshell, why is ECC capable memory more desirable?

http://en.wikipedia.org/wiki/ECC_memory#Error-correcting_memory

Not the best description but it will suffice.

In a nutshell, to quote from the Wiki page:

"ECC memory provides greater data accuracy and system uptime by protecting
against soft errors in computer memory."

However, it comes at a price. It depends on what you're using your PC for
really. I have two PCs with ECC RAM and the rest without. IMO for
non-mission-critical machines its' not really needed.
--
TTFN

Shaun.

External Since: Dec 17, 2005 Posts: 143

Igor wrote:
> I'm planning to add some memory to a PC. The motherboard supports "DDR
> up to 333 MHz (enhanced) memory bus."
>
> 333 MHz (PC2700) or slower DDR SDRAM isn't easy to find on today's
> market, and when you do find it, it's considerably more expensive than
> the DDR which runs at 400 MHz (PC3200). What would happen if I bought
> 400 MHz DDR RAM and installed it in a motherboard which only supports
> speeds up to 333 MHz (PC2700)? Would it work? If it did work, would it
> work as well as the slower PC2700 RAM?
>
> I've gotten conflicting answers to this question. Two computer stores
> told me that it wouldn't work. Another store and a book I consulted said
> it would.

I'll bet the boys in the first two shops were confused between DDR vs.
DDR2 DRAM. The type of memory you're getting is just DDR memory, and
therefore any memory that conforms to the DDR standard will work on your
mobo. Even slower ones, but they'll just run slower on your system, of
course.

Currently, the most popular type of memory is DDR2, so the older DDR
memories are being phased out, and likely the only stock that is left is
the fastest versions of DDR. So that's why you can't find DDR-333/PC2700
memory anymore, because now they only stock the fastest DDR-400/PC3200
memories. On the other hand, if you were interested in DDR2 memory, then
you'll have all kinds of choices such as DDR2-533/PC4200,
DDR2-667/PC5200, or DDR2-800/PC6400.

> I'd also like some opinions on which brand of RAM I should get. Kingston
> and Samsung are ubiquitous where I live, so the choice comes down to one
> of those. Both brands are about the same price, with the Samsung being
> marginally cheaper.

Brand-name doesn't matter, just make sure you buy two of exactly the
same brand at the exact same time, if you're going to be matching it up
for dual-channel operation, otherwise that'll show up as single-channel.

Dual-channel vs. single-channel is another way of increasing the speed
of Dram, with dual-channel being faster than single-channel, obviously.

> Finally, would a 128 MB stick of 266 MHz DDR RAM be able to run in the
> same computer as, say, a 512 MB stick of 400 MHz DDR RAM? If so, would
> using both at the same time degrade the performance of the faster RAM?

Yes, the faster RAM would be slowed down to the speed of the slower RAM.
So it's best to completely remove the old RAM, if you want to gain the
performance advantage of the newer RAM.

As for mail-ordering within Canada, try this site:

www.pricegrabber.ca

Personally, I prefer to do my business with bricks'n'mortar stores
rather than online.

Yousuf Khan