DDR/SDRAM???

[Zed Rafi]

Hello NG,

I'm confused.
I want to buy an extra 512 Meg of RAM for my girlfriend's computer.

I ran AIDA32 to check whicg type of RAM compatible with the MOBO. It tells
me that i have PC2100 DDR SDRAM. It also seems that memory speed is 266MHz.
If anyone would please like to double-check this info, the MOBO is a
Gigabyte GA-7VM400M.

Don't know much about memory, but i thought SDRAM and DDR were different
types of RAM... can anyone explain the difference to me?

Also, if the mobo takes various types of RAM, can i install different types
of RAM in the computer or is it preferable to stick to same type of RAM?

what do you guys think of "Generic RAM"? Must i absolutely avoid it? What's
a reliable brand for value RAM?

Also, i want to buy a 200 gig IDE hard drive. Any brands you think i should
avoid? I've had a bad experience with Maxtor drives (back in the days when a
16 Gig hard drive was considered to be super slick)

thank you very much

 

[John Fryatt]

Hello NG,

I'm confused.
I want to buy an extra 512 Meg of RAM for my girlfriend's computer.

I ran AIDA32 to check whicg type of RAM compatible with the MOBO. It tells
me that i have PC2100 DDR SDRAM. It also seems that memory speed is 266MHz.
If anyone would please like to double-check this info, the MOBO is a
Gigabyte GA-7VM400M.

Don't know much about memory, but i thought SDRAM and DDR were different
types of RAM... can anyone explain the difference to me?

Also, if the mobo takes various types of RAM, can i install different types
of RAM in the computer or is it preferable to stick to same type of RAM?

what do you guys think of "Generic RAM"? Must i absolutely avoid it? What's
a reliable brand for value RAM?

Also, i want to buy a 200 gig IDE hard drive. Any brands you think i should
avoid? I've had a bad experience with Maxtor drives (back in the days when a
16 Gig hard drive was considered to be super slick)

There's manual for your motherboard here:
http://europe.giga-byte.com/MotherBoard/FileList/Manual/manual_7vm400m(f)_e.pdf
That's revision 1. There's one for revision 2 as well.

Apparently you have two 184-pin DDR RAM sockets, and the motherboard
supports DDR333, DDR266 and DDR200 memory.

This article explains RAM designations:
http://en.wikipedia.org/wiki/SDRAM

Basically DDR memory is properly called DDR SDRAM. SDRAM designates the
basc design of the memory. 'Normal' SDRAM could, I suppose, be
reprospectively called SDR SDRAM, meaning Single Data Rate. DDR is the
same basic design but the memory is read/written twice in a clock cycle,
hence Double Data Rate.

If your motherboard accepts various speeds of memory, as your does, and
you mix them, it will either not work or set itself to the speed of the
slowest component*. So, it's not worth mixing unless you happen to have
ended up with a mixture. If you are buying new, either get more to match
what you already have or ditch the existing and get all new faster memory.
(* - some BIOSes might have a means of forcing the RAM to run at a
certain speed. If you do this and make a component to run at a faster
speed than it's rated at it might or might not work - not worth it in my
opinion.)

Speed-wise there are two ways of expressing it. DDRnnnn and DDRnnn. For
example DDR2100 is the same as DDR266.
The data bus for memory is 64 bits wide so 64/8 = 8 bytes are read in
each cycle. If the FSB runs at 266MHz that is 266,000,000 * 8 bytes per
second = 2128MB, rounded to 2100 (because it sounds snappier I
suppose). Hence DDR266 (FSB speed_) = DDR2100 (max. data rate).

Note that you don't get any benefit by simply putting 'faster' RAM into
your system, The FSB has to be set to an appropriate speed to take
advantage of the faster RAMs capability. Often, as in your case I think,
the BIOS will do that automatically.

Re. brands, I feel happier using some recognised brand, like Micron. You
might get away with 'generic', just depends how you feel about it I
think. Do you like to feel safe(r) or are you more of a risk taker? ;-)

Re. hard disks, I have Western Digital, Seagate, Maxtor, and Fujitsu in
PCs here, and they all seem fine. In fact, I've never had a hard disk
fail at all. Others with more experience in this area might have some
thoughts though.

 

[DaveW]

DDR is an advanced type of SDRAM. Your computer, as it says, needs PC2100
DDR RAM. I would stay away from real cheap RAM; it will undoubtedly give
you headaches using it.
As for the 200 GB harddrive, if you are intending to put it in this computer
I doubt, based on the speed of RAM used, that the motherboard's BIOS can
recognize any harddrive larger than 137 GB. It is undoubtedly an older
BIOS.

 

[Zed Rafi]

As for the 200 GB harddrive, if you are intending to put it in this
computer
I doubt, based on the speed of RAM used, that the motherboard's BIOS can
recognize any harddrive larger than 137 GB. It is undoubtedly an older
BIOS.

how can i check if the MOBO's bios supports drives larger than 137 Gb?

can this limitation be fixed by loading in the latest BIOS version?

 

[kony]

Hello NG,

I'm confused.
I want to buy an extra 512 Meg of RAM for my girlfriend's computer.

I ran AIDA32 to check whicg type of RAM compatible with the MOBO. It tells
me that i have PC2100 DDR SDRAM. It also seems that memory speed is 266MHz.
If anyone would please like to double-check this info, the MOBO is a
Gigabyte GA-7VM400M.

Forget about what AIDA tells you, your board chipset
dictates what it can use and for that board you should get
PC3200 memory, even if your memory bus speed is currently
lower than 200MHz/DDR400, because PC3200 is not just
"backwards compatible", it is actually the same memory as
lesser PCxxxx grades except guaranteed to be able to run
faster too, giving it more stability margin and more
potential to reuse it later. It also doesn't hurt that it's
about the same price as lesser memory.

Also, if the mobo takes various types of RAM, can i install different types
of RAM in the computer or is it preferable to stick to same type of RAM?

You can mix n match and even if you tried to buy *same*
memory you had, after time has passed you'd still
essentially be mixing and matching memory because (by any
reasonable odds) it wouldn't have the same lot of chips on
it as your current one does. If the memory isn't stable
it's same situation as always, return it to reseller or try
to make bios memory timing adjustments.
Run memtest86+ to check stability before ever booting
windows or other operating system after any memory changes.

what do you guys think of "Generic RAM"? Must i absolutely avoid it? What's
a reliable brand for value RAM?

yes it's best to avoid generic, the gamble is hardly worth
the minor price difference between generic and on-sale
value-grade name brand memory. Plus, if you had a dozen
systems and the generic didn't work in one there might be a
chance to swap some memory around so all systems are happy,
but when targeting one system alone it is more prudent to
have greatest odds of success, since the merely cost or time
of returning a product can easily exceed a price difference.

Also, i want to buy a 200 gig IDE hard drive. Any brands you think i should
avoid? I've had a bad experience with Maxtor drives (back in the days when a
16 Gig hard drive was considered to be super slick)

There is no reason to avoid current makes or models based on
failure of a different model. All manufacturers have minor
issue from time to time, and random failures. What
happened to a 16GB drive would have no bearing on today's
maxtors. Even so, without reason to choose a specific drive
you might consider a Seagate as their 5 year warranty on
their basic drives is longer than other similar brand
offerings.