Memory banks

[Shodan486]

I'm a bit confused how the memory banks are used, or even how it works...

How many banks do I have when I have 2 512MB modules installed VS 1 1GB module? Or do I have to populate all available (for example 4) DIMM slots to get all memory banks (0 to 7)? How many banks do I obtain using one DIMM module, for example a 256MB one?...Sorry, can't find an useful article, need to browse some of my books though...

[washu]

Re: Memory banks

Memory banks are not as simple as the number of DIMMs installed. DIMMs can be "single-sided" or "double-sided" indicating one or two banks respectively. You could have two single-sided 512 MB modules or a double-sided 1 GB module and they both would be using two banks.

You could populate all 4 DIMM slots with single-sided chips and then you would only be using banks 0-3 or possibly 0, 2, 4, 6 depending on how the memory system is setup.

Note that they physical presence of chips on both sides of a DIMM does not necessarily make it double-sided. It depends on the density of the RAM chips used and how they are organized.

[Shodan486]

Re: Memory banks

Does different DIMM population (single-sided, double-sided, low VS high density chips) mean any performance increase / decrease?

[washu]

Re: Memory banks

If the speeds of the modules are the same then it does not matter. Performance will be the same.

What can sometimes cause issue is when the chipset does not support having 2 banks for every slot. For example some chipsets support only 4 banks, but the MB has 3 slots. If you filled them all with double sided modules that would make 6 banks which would not work. I have not seen this problem on any recent motherboard.

If your motherboard supports dual-channel then having two modules is better than one, but the configuration of the modules themselves doesn't matter as long as they are both the same.

[Shodan486]

Re: Memory banks

It is the Abit VP6, having 4 SDRAM DIMM slots and using all of them - I use double sided, but not knowing what density, it's basically these - http://cgi.ebay.co.uk/512-mb-512mb-1...mZ120524412981

the bank interleave is set to 4-way, just fyi.

[kaniki]

Re: Memory banks

that is more server or ECC memory.. most motherboards for stand alone computers or personal computers do not use, nor will they recognize ECC memory. I am not sure about your motherboard but you will have to check to make sure that it is compatible.

as for the brand, most, if not all kingston brand memory is low density. but can not check for sure without the model number. low density memory is usually supported by pretty much all motherboards, but high density memory is only supported by say half of the boards out there.. you would have to check with the manufacturer of the motherboard to know for sure. If it is a custom, then you have a 50% chance high density will work. If it is a pre-built system (HP, Compaq, Dell, etc.) then best to stick with low density.

also, i do not know what computer that you are putting this in, but this is SD-RAM. If you have a newer computer, then this will not work. SD-RAM was used on computers with speeds of up to about 1 GHz or 1000 MHz. anything over 1 GHz most likely will use DDR-RAM which includes DDR DDR2 DDR3 RAM. and there are different speeds for each. For example SD-RAM comes in PC 66 100 and 133 and regular DDR comes in PC 1600 2100 2700 and 3200 and as in each number, the higher the number the faster the ram. If you use PC 2100 DDR in a computer that supports 3200 DDR RAM, then it will lower the speed and performance of the computer as well.

IF you do not know what kind of motherboard or RAM that your system uses, i would say try out everest and install that and it should give you some answers to what is installed right now.. they have a free trial..

http://www.lavalys.com/products.php?lang=en&page=11

hope that helps