Difference in computer memory?

**brettw22** · 03-12-2005 09:27 PM

To those who are savy about this stuff.....

I need to get some memory for my laptop, but what's the difference between SDRAM and SODIMM? I'm looking at a few places and see that the SODIMM is priced lower than the SDRAM.......why?

**janmike** · 03-12-2005 09:41 PM

Here is a site that will provide the definition.

Memory Terms Glossary

**brettw22** · 03-12-2005 10:58 PM

OK, but from a performance perspective, they shouldn't be different? That was ultimately my original question.

**bobman1235** · 03-13-2005 12:20 AM

Originally posted by brettw22
OK, but from a performance perspective, they shouldn't be different? That was ultimately my original question.

I'm pretty sure SODIMM refers to the form factor (as in, small, deisgned for a laptop) whereas SDRAM is a technology - as in "Synchronous... uh... something random access memory".

Chances are your SODIMMs are actually SDRAM in a SODIMM format, so comparing them... pretty much makes no sense.

I'm 90% sure that what I just said is true... :)

EDIT : the D stands for "Dynamic." Had to look taht up, it was driving me nuts.

**brettw22** · 03-13-2005 12:32 AM

Hmmmm...odd.

The only reason that I asked was Toshiba's website offers the 2 different memory types for this model laptop, with the price being $75 higher on the SDRAM vs. the SODIMM.

I called Tosh's tech support and they told me to call Kingston......blah.

I was just thinking it's a performance thing, because their website shouldn't give me standard memory options for a laptop, and the price difference between the notebook and standard memory would be MUCH greater than $75.

**PolkThug** · 03-13-2005 12:38 AM

You're thinking about this all wrong. Think of the DIMM as the chassis and the RAM (SDRAM, DDR, etc.) is what goes on the DIMM, that you slide into your computer.

Regards,
Polk "Got my first 'computer license' at age 10 in 1983" Thug

**PolkThug** · 03-13-2005 12:43 AM

Originally posted by bobman1235
EDIT : the D stands for "Dynamic." Had to look taht up, it was driving me nuts.

Actually, it stands for "Dual". Before there were DIMM's there were SIMM's. SIMM = Single Inline Memory Module, DIMM = Dual Inline Memory Module.

Regards,
PolkThug

**PolkThug** · 03-13-2005 12:46 AM

Originally posted by bobman1235
I'm pretty sure SODIMM refers to the form factor (as in, small, deisgned for a laptop)

This is true, SO = Small Outline (smaller form for laptops).

**brettw22** · 03-13-2005 12:46 AM

OK, so what's the difference between THIS and THIS?

**PolkThug** · 03-13-2005 12:52 AM

Originally posted by brettw22
OK, so what's the difference between THIS and THIS?

Ironically, the more expensive one is for a slower motherboard.

They are both 1GB DDR SDRAM SODIMM's.

One is for 2700 333 (faster front side bus), and the other is for 2100 266.

Regards,
PT

**brettw22** · 03-13-2005 01:08 AM

The 2700 and 2100 that you're talking about aren't referring to the PC2100 type, are they? (i don't see a differentiation between the two on those pages)

**PolkThug** · 03-13-2005 01:12 AM

Yep, looks like they got a typo, they say 2.1gHz bandwidth on both pages, one should say 2.7.

2100 = 2.1
2700 = 2.7

**brettw22** · 03-13-2005 01:15 AM

OK....so as long as I order PD2100 SDRAM i'll be good (in SODIMM form)

**PolkThug** · 03-13-2005 01:43 AM

Originally posted by brettw22
OK....so as long as I order PD2100 SDRAM i'll be good (in SODIMM form)

The important question is what is the front-side bus (FSB) of your laptop? (ie 266, 333, 400)

**brettw22** · 03-13-2005 01:59 AM

Just looked at the specs HERE and it appears that it's 800.......though I don't know if I'm looking at the right thing.

**PolkThug** · 03-13-2005 03:55 AM

Okay, go with the faster one (PC2700/333):

http://www.memoryx.net/ktt33111g.html

**brettw22** · 03-13-2005 04:01 AM

Wow.......the memory game I don't get........

I thought that the 2100/2700 numbers indicated some sort of size of the chipset.

I guess it can't ever hurt to give it faster memory than it would typically run (like giving a 100wpc speaker a 200wpc amp), but it just won't utilize all that the memory itself is capable of, right?

**PolkThug** · 03-13-2005 04:06 AM

The front side bus is like a highway between your RAM and your CPU and a couple other things (depending on layout).

Your highway can let cars go 400MPH, the PC2100 limits the cars to 266MPH, and the PC2700 will let them go 333MPH.

Regards,
PT

**brettw22** · 03-13-2005 04:11 AM

Where in that pdf did you see that my pc was 400 FSB?

EDIT: If my PC does have the 400FSB, wouldn't I be even better off by going with PC3200 DIMMS?

**PolkThug** · 03-13-2005 12:18 PM

Originally posted by brettw22
Where in that pdf did you see that my pc was 400 FSB?

EDIT: If my PC does have the 400FSB, wouldn't I be even better off by going with PC3200 DIMMS?

I was guestimating. On the Toshiba site, the 333 stuff comes up as compatible, so that would be the safest bet. Try to ask them if PC3200/400 is compatible with your model.

Marketing seems to have a hand in this, they advertise an "800" bus on the PSB, but fail to mention the bus speed for the RAM.

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