DDR PC 2100 vs DDR PC 3200

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Gary

What's the difference between DDR PC 2100 and DDR PC 3200 ? I think
even DDR PC 3200 acually operates at 400 MHz so why the numbers up
front ? Excuse my lack of knowledge, it's been 4 or 5 yeats since I've
put together my current system using PC 100 memory that operated at
the same speed as the PCI bus.

Thanks in advance.

Gary
 
Gary said:
What's the difference between DDR PC 2100 and DDR PC 3200 ? I think
even DDR PC 3200 acually operates at 400 MHz so why the numbers up
front ? Excuse my lack of knowledge, it's been 4 or 5 yeats since I've
put together my current system using PC 100 memory that operated at
the same speed as the PCI bus.

Thanks in advance.

Gary
Click to expand...

2100 = 266
2700 = 333
3200 = 400

I dont know who dreamed up the numbers on the left!

Now if the price difference is small its usually better to get the fastest
one available. It may whether an upgrade or two and has higher resale
value.
 
tghe numbers dreamed up on the left are bandwidth numbers (in theroy). ie.
PC 2100 has a bandwidth of 2.1G/sec and operates at 266Mhz. PC 3200 has a
bandwidth of 3.2G/sec and operates at 400Mhz. All in theroy though. to
get the effective bandwidth your FSB has to match.I run PC3200 with a
XP2100+ which only has a FSB of 266 so I am runnign the ram at 133x2 (dual
channel) which gives me 2.1G/sec. I got the PC3200 RAM ready for my upgrade
to a faster CPU which hasn't happened yet.
 
DDR means double data rate. The 400Mhz you see is 200Mhz DDR. PC3200 is the
theoretical bandwith that it provides at that clock rate. PC 100 does not
operate at the speed of the pci bus, the pci bus runs at 33Mhz.
 
Gary said:
What's the difference between DDR PC 2100 and DDR PC 3200 ? I think
even DDR PC 3200 acually operates at 400 MHz so why the numbers up
front ? Excuse my lack of knowledge, it's been 4 or 5 yeats since I've
put together my current system using PC 100 memory that operated at
the same speed as the PCI bus.

Thanks in advance.

Gary
Click to expand...

The 2100, 3200 are a relative description of potential bandwidth of the RAM.
DDR400 actually operates at 200MHz. (dual data rate, or ~400MHz)

Generally, DDR400 (aka PC3200) is what you want, if your motherboard
supports it. PC2700 will only work with certain processors and PC2100 will
work with even fewer processors. For example, if you have PC2100 RAM, most
motherboards won't allow you to use a 800FSB processor, such as an Intel P4
Prescott 800FSB. With PC2100 (DDR266) you CAN use a 400FSB or 533FSB
processor. With PC2700 (DDR333), you can use 400FSB, 533FSB or 800FSB CPU.
But, if you use a 800FSB processor, your RAM will be underclocked to
clock-doubled 160MHz (essentially making it DDR320, if there was such a
thing).

There are other types of RAM such as DDR2 (just coming out, you will know if
your motherboard requires it) and PC3500 and PC4000 (not official, just a
marketing gimmick, implying that you can overclock this DDR400/PC3200 RAM so
that it has higher bandwidth) -Dave
 
cowboyz said:
tghe numbers dreamed up on the left are bandwidth numbers (in
theroy). ie. PC 2100 has a bandwidth of 2.1G/sec and operates at
266Mhz. PC 3200 has a bandwidth of 3.2G/sec and operates at 400Mhz.
All in theroy though. to get the effective bandwidth your FSB has to
match.I run PC3200 with a XP2100+ which only has a FSB of 266 so I am
runnign the ram at 133x2 (dual channel) which gives me 2.1G/sec. I
got the PC3200 RAM ready for my upgrade to a faster CPU which hasn't
happened yet.
Click to expand...

So what should my 2100 be running at? 133? If this is changed does it make a
difference to the PC's efficiency?
 
So what should my 2100 be running at? 133? If this is changed does it make
a difference to the PC's efficiency?
Click to expand...


Yes, and yes. But you won't notice a significant difference, unless you
overclock it past the point where it becomes massively unstable. -Dave
 
tghe numbers dreamed up on the left are bandwidth numbers (in theroy). ie.
PC 2100 has a bandwidth of 2.1G/sec and operates at 266Mhz. PC 3200 has a
bandwidth of 3.2G/sec and operates at 400Mhz. All in theroy though. to
get the effective bandwidth your FSB has to match.I run PC3200 with a
XP2100+ which only has a FSB of 266 so I am runnign the ram at 133x2 (dual
channel) which gives me 2.1G/sec. I got the PC3200 RAM ready for my upgrade
to a faster CPU which hasn't happened yet.
Click to expand...
I am curious about the opposite situation. I currently run a AMD 1.4
GHz T-Bird in a Asus A7M266 motherboard using PC2100 memory.
I am thinking about building a new system with an AMD 64 cpu. I
realize it won't run at maximum speed if I do this, but is it possible
to use the PC2100 memory in the new mobo to test it? I would buy the
system piece by piece as money allows and wish to test the various
parts while they can still be returned. I would buy the new mobo and
cpu at the same time and install this memory until money permits
upgrading to the proper type. If it's possible, wouldn't I have to set
some custom values in the BIOS memory section?
 
Dave C. said:
Yes, and yes. But you won't notice a significant difference, unless you
overclock it past the point where it becomes massively unstable. -Dave
Click to expand...

Had some PC 2100 running 380Mhz stable some time ago.
Made ? Don´t remember.
Give it a try..
G.
 
Capman said:
I am curious about the opposite situation. I currently run a AMD 1.4
GHz T-Bird in a Asus A7M266 motherboard using PC2100 memory.
I am thinking about building a new system with an AMD 64 cpu. I
realize it won't run at maximum speed if I do this, but is it possible
to use the PC2100 memory in the new mobo to test it? I would buy the
system piece by piece as money allows and wish to test the various
parts while they can still be returned. I would buy the new mobo and
cpu at the same time and install this memory until money permits
upgrading to the proper type. If it's possible, wouldn't I have to set
some custom values in the BIOS memory section?
Click to expand...

As long as the board you buy lets you run the memory async then youll be
fine. so you can run your cpu fsb at 166 (x2=333) (or whatever the AMD64 is
at these days. I haven't kept up with it) and your ram at 133 (x2=266). You
will still get a boost in performance over the 1.4 CPU but the RAM will
still be holding back the AMD64
 
So what should my 2100 be running at? 133? If this is changed does it
make a difference to the PC's efficiency?
Click to expand...

yes. 133x2 = 266. PC effiency. You can overclock it as much as you want
but no point in having your RAM at 200 and your CPU at 133. YMMV
 
Howdy!

Gary said:
What's the difference between DDR PC 2100 and DDR PC 3200 ? I think
even DDR PC 3200 acually operates at 400 MHz so why the numbers up
front ? Excuse my lack of knowledge, it's been 4 or 5 yeats since I've
put together my current system using PC 100 memory that operated at
the same speed as the PCI bus.
Click to expand...

3,200 million bytes per second ... that's 400MHz x 8 bytes per
transfer (being 64 bits wide).

PC 2100 is actually 2,128 million bytes per second, but it's easier
to say PC2100 than PC2128 B)

RwP
 
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