DDR2 Upgrade help please

stu_h

stu_h

stu_h

Associate
Joined
28 Mar 2008
Posts
12
Hi.
I'm trying to upgrade a Gigabyte GA8I91P Duo Pro board for my nephew. He has 1GB DDR ram at the moment suing 2 512MB sticks in dual channel mode. The board has 2 DDR slots and 2 DDR2 slots. We are looking to upgrade to 2GB DDR2 using 2 1GB sticks.
The board spec states it supports 1.8V DDR II DIMM and dual channel DDR II 533/400 DIMM.
I have been a bit confused about what what voltages and speeds we can fit. I though that we could only use 1.8V rated DDR2 running at 533MHz max so was looking for PC2 4200. BUT.... having found that this seems to be pretty hard to find now we have started looking at PC2 5300 or higher.
I had an online chat with a Crucial helper who told me that we can use ANY DDR2 memory and the board will auto-adjust. This confused me and I still have some questions.

Can we use 2.2V rated ram in this 1.8V board OK? Aren't there physical notches on the sticks that would prevent insertion or are the notches the same for all DDR2 (and different to DDR'1')? If 2.2V rated will work OK then why do manufacturer's quote either 2.2V or 1.8V? Is it that those rated at 1.8V are less over-clockable as they won't handle the higher voltages (I'm assuming that over-clocking the ram needs the voltage to be raised?)? What I mean I suppose is that the quoted voltages are the maximum recommended voltages so all 2.2V DDR2s will work at 1.8V but not all 1.8V DDR2s will run at 2.2V.
Is another issue whether the board will allow the voltage to be changed from 1.8V in steps up to 2.2V etc?

Can we use higher speed rated DDR2 without any problems? I.e. could we fit PC2-8500 without any problems and they will happily downgrade and run at the board's 533MHz rather than the rated 1066MHz?

So...... is it just a price issue effectively? If I try and get PC2-4200 (if I can find any) I would pay less but get the SAME performance than if I bought PC2-8500 running at the same board settings? The only difference would be if we started trying to overclock it, the PC2-4200 would be FAR FAR less overclockable than the 8500. If this is the case, and price was not the issue, why don't all memory sellers just sell the highest speed DDR2 with the highest voltage rating? This would allow it to be used in any DDR2 board.

Apologies if I'm being a bit dim here and I've missed the point somewhere along the line!
Thanks.
 
You are getting confused with voltage and DDR, the two are not the same (though yes each new DDR usually has lower voltages).

The official spec for DDR2 is 1.8 volt and all DDR2 should be 1.8 to comply but performance memory often uses higher voltages than this (to achieve the higher clocks). All boards that support DDR2 will support 1.8 volt memory but may (or may not) support the option in the BIOS to choose a higher voltage (you can check that easily). Whether higher voltage memory will support running at 1.8v depends on the memory but if it explicity states a higher voltage then it is unlikely it would work at the rated frequency at 1.8 volt but may work if you use lower.

Memory should be backwards compatible and is usually programmed to support speed grades below what is rated but you can't guarantee that plugging 2.2v PC2-8500 in, it will revert to and function at 533 / 1.8 volt.

The only difference would be if we started trying to overclock it, the PC2-4200 would be FAR FAR less overclockable than the 8500
Click to expand...
Yes but even with the latest CPUs you don't memory that high.

I would suggest for compatibility sake (if you have intention of keeping the PC awhile) you get 1.8v 533 Mhz memory which you say is officially supported by the board and should have no problems. It could also be used with 1066 FSB CPUs in the future if you upgrade to Core 2 (but obviously not the latest 1333 CPUs).
 
have a look at :

Crucial 2GB (2x1GB) DDR2 PC2-5300C5 Dual Channel Kit (CT2KIT12864AA667) £30

runs at 1.8v
 
Thanks for replying.
I don't think I was getting 'that' confused between voltage and DDR. The confusing part was that some DDR2 is quoted as 1.8V (as per the official spec.) but some is quoted as 2.2V and I wasn't sure if it would operate on a 1.8V motherboard with, I think, only about a +0.3V adjustment. I think you (Tetras) have answered that, thank you. I guess the only grey area is knowing what speed the 2.2V rated faster memory (e.g. PC2-8500) would run at IF IT WOULD RUN when pluged into a 1.8V board. Maybe the solution is to only use memory that states 1.8V and avoid any 2.2V?
The Crucial memory you mentioned (mp260767) looks good to me and I think was one that I had already looked at.
My nephew was hoping to get some of those whizzy LED modules but I guess we'll go for the plain ones!

Thanks again to you both.
 
There's really no point in getting 2.2v memory if you can't supply more than 1.8v. It would work in the board, but only at about the same speed as the Crucial kit mp260767 has recommended. So it would be a waste of money.
 
Thanks. Are you saying what Tetras said? 2.2V ram will work on a 1.8V board but not necessarily at the ram's max speed? Is that all 2.2V or is there stuff out there that will not run at 1.8, i.e. the manufacturer's spec would implicitly state to use 2.2? How would anyone know what speed would be reachable if the ram is operated at 1.8 not 2.2? I don't expect the spec would tell you so would it be a case of trial and error?
I will just buy 1.8 but I'm now curious!
Thanks again.
 
Yip I'm agreeing with Tetras.

2.2v memory won't get far above PC5300 speeds at only 1.8v. You *may* get as far as PC6400 speeds with 5-5-5-15 timings, but it would still be a waste of money.
 
You must log in or register to reply here.
Back
Top Bottom