P4PE and ram ?

[lupi]

Just rebuilt a new box with a 2.8 on an ASUS P4PE. 2 of the memory slots are shared so I can only use 1 double or 2 single sided modules there. I only have a single 256 module now, and am not sure if that is considered single or double. It does have 4 chips per side but can not find any technicall reference stating details of. Just want to know before I pick up another module to get my total to 512 or more.

 

[corkyg]

I have twp P4PE machines with 2.53s, and each has two sticks of 512 MB in slots 1 and 2. The have chips on two sides, but are technically not "2 sided." They are Corsair PC-3200. They work perfectly - very stable.

 

[LegionX]

why arent they technically considered doublesided? i have a stick of samsung 512 DDR 333 that has chips on both sides and figured it was double sided which sucks becuase my msi 648 max-L can only handle 3 banks and so cant get another stick of the same memory. could i be wrong about my memory then?

 

[lupi]

Originally posted by: LegionX
why arent they technically considered doublesided? i have a stick of samsung 512 DDR 333 that has chips on both sides and figured it was double sided which sucks becuase my msi 648 max-L can only handle 3 banks and so cant get another stick of the same memory. could i be wrong about my memory then?

Thats exactly my question to, can't find anything that says a chip is or isn't "double sided".

 

[LegionX]

anyone know?

 

[LegionX]

Originally posted by: corky-g
I have twp P4PE machines with 2.53s, and each has two sticks of 512 MB in slots 1 and 2. The have chips on two sides, but are technically not "2 sided." They are Corsair PC-3200. They work perfectly - very stable.

Bump
corky what did you mean by this?

 

[corkyg]

Ask PastorJay - he told me, and I followed his advice and it worked. Apparently there are single sided memory modules that are butted together so there appear to chips on both sides - but they are not functionally "double sided."

Case in point - the Corsair XMS PC 3200 sticks with heat spreaders are functionally single sided.

Sorry to be late - I'm on the road to San Diego in the morning.

 

[RadioactiveMagpies]

taken from crucial support website:

What do the terms "double-sided" and "single-sided" mean?
Solution:

A module that has chips on both sides of the printed circuit board is said to be double-sided, and a module that only has chips on one side of the printed circuit board is single-sided. In most cases, double- and single-sided modules can be used interchangeably. In fact, if you have two 64MB modules, one may have chips on one side, while the other has chips on both sides, and the two can be used together in most systems. If your system requires only single-sided or only double-sided modules, those requirements are built into our Memory Selector.

your asus p4pe has 3 slots, you can use a double sided or single on slot 1 - slot 2. If you want to use all 3 slots, you will have to buy two single sided ones to fill slots 2 and 3. So if you get another double sided stick, you won't be able to use the 3rd one. If you want to get to 768 in the future, you'll need to make sure the next chip is single sided.

 

[VirtualLarry]

Originally posted by: LegionX
why arent they technically considered doublesided? i have a stick of samsung 512 DDR 333 that has chips on both sides and figured it was double sided which sucks becuase my msi 648 max-L can only handle 3 banks and so cant get another stick of the same memory. could i be wrong about my memory then?

The terms "single-sided" and "double-sides" refer more in terms of the electrical connections, not the physical construction, although they are often the same (but not always).

Generally speaking (at least from the days of 72-pin SIMMs, not sure if DIMMs are the same), there are a limited number of RAS (row address strobe/"bank select") lines coming off of the chipset and wired to the memory slots. Depending on the number of memory slots and RAS signals available, some of those RAS lines may actually be wired to more than one memory slot, both to the second ("backside") RAS signal of one memory bank, and the first ("frontside") RAS signal of another. Now, I understand that DIMMs are internally banked, and generally are referred to as "DIMM x" instead of "BANK x" of memory. So I'm not sure if this is still directly applicable or not. But the general principle is the same - some memory slots share signals with others, and "double-sided" memory uses a pair of these signals, whereas "single-sided" only uses one set. (The general address lines are always shared with every bank.)

So in your case, the chipset only handles 3 "banks" of RAM, and that DIMM that you have, is "double-sided", and therefore uses up two of those banks, leaving only a single bank-select/RAS line free. So you cannot use an additional double-sided DIMM, you may only use one that is single-sided.

 

[lupi]

But this still leaves the question, how do we determine if the chip we have is electrically single or double sided.

 

[VirtualLarry]

Originally posted by: lupi
But this still leaves the question, how do we determine if the chip we have is electrically single or double sided.

Older BIOSes (AWARD) on mobos/chipsets using SDRAM, during bootup, would say: "SDRAM in BANK: " and then list an ordered set of numbers, counting from 1 to whatever the max memory bank supported by your board/chipset was.
If a DIMM was double-sided, it would show up as taking up two banks in that list. Single-sided DIMMs would only show as one bank. My newest SocketA board using DDR has an AMI BIOS, not sure if it shows up the same way.