Difference Between Double Sided and Single Sided Ram

[antsct]

Hello everyone.

As I posted not long ago, I'm setting up a home web server soon. It's a an old PC but sill in great condition. Specs are:

533MHZ AMD K6-2
Onboard 8mb graphics
Windows XP Pro SP2
8Gb HDD (will also more than likely add another 30gb drive)
320mb SDRAM.

OK, I know how to set everything up BUT I need help with one thing. Currently the PC has 320mb sdram. 1x 256mb Doubled Sided 133MHz memory stick and 1x 64mb Single Sided 133MHz (I think, could be 100MHz) memory stick. Now I want to upgrade it to it's max supporting, 512mb SDRAM 133MHZ. To do this I want to add another 256mb 133MHz. The thing I dont know is, does doubled sided add any preformance gains or is it needed for my PC to use 512mb ? Doubled Sided is a lot more expensive that single sided.

Thanks.

 

[antsct]

If anyone can help out then please do.

 

[JimPhelpsMI]

Hi, Not sure about the very latest, but double sided was originally a way to double the memory size using currently available chips. Thus 8 (Chips)X 2 X 128 X 1 X 128 became 256. Hope this helps a bit, Jim


Hi, I suspect that the chip count misconception comes from the fact that way back in history mem cards came as 8 chips or 9 chips. The ninth chip was for parity. A check on correct memory operation. 8 chips had no parity. As mem got more reliable the 9th chip was omitted. Jim

 

[V00D00]

I don't think it really matters. I don't think there's a difference.

I know when there are 2 sides usually they act as 2 banks. In which case you can enable bank interleaving. Bank interleaving is like the old version of dual channel. I ran some benchmarks and bank interleaving increases the memory bandwidth pretty dramatically. A PC100 stick with bank interleaving was like 10MB/sec less than PC133 without bank interleaving.

So get yourself some double siders and enable bank interleaving. How much more expensive are they??

 

[cubby1223]

Not all motherboards can work with all chip densities. In a double sided 256mb stick, each chip holds 128mbits. In a single sided 256mb stick, each chip holds 256mbits.

In your situation with an older motherboard like you have, it likely will not accept single sided 256mb ram, but should take double sided 256mb ram.

 

[Blain]

Double sided adds no performance vs. single sided. It's all about motherboard compatibility.
The price difference you're seeing is probably due to one module being "Low Density" and the other "High Density".

 

[V00D00]

Here's a link I found in another thread that's supposed to explain the difference. I haven't read it though:
double sided vs single sided

 

[antsct]

Thanks for the help guys. The thing is, the PC originall came with a 64mb Single Sided stick which I think is PC100. It works perfectly with my 256mb PC133 Double Sided so does that mean a single sided 256 PC133 should work?

 

[Jhhnn]

Not necessarily. Single sided 256 meg sticks have different memory geometry than double sided sticks, the double sided ones actually being divided into 2 memory banks of 128 megs each... older chipsets can't address more than 128megs/bank... so it really depends on the chipset...