Mixing Memory

[rwinegar]

I have a Dell T5400 with two sticks of 1GB memory at 667MHz. I have a 1GB stick at 677MHz that I want to add. Both are fully buffered and sold by Dell specifically for the T5400.

Can I combine the 667MHz and 677MHz memory without causing any problems?

[bistro]

Those are so close you wouldn't have any problems at all. I suspect their latencies are identical.
Edit: I just looked that system up and noticed it may have only 2 DIMM slots. Looks like what you have in there is TWO 512mb sticks for a total of 1GB. is this correct? If so, replacing one of the sticks with a 1GB will only give you 1.5Gb total.

[photolady]

According to Dell you must install those memory in pairs. So, you already have to slots filled, you need to install 2 1gb modules, not one. So the answer is no, you can't do it that way.

[bistro]

I stand corrected.

[rwinegar]

The computer has 8 DIMM slots and 2 sticks of 1GB DDR2 SDRAM 667MHz.

http://www.dell.com/content/products...tab=bundlestab

I think adding one stick of 677MHz will simply cause that stick to match the speed of the other two and run at 667MHz.

I know I came here asking for help. Be that as it may, I must still respectfully disagree with photolady. I am about 90% sure this combination will work.

Anyone else care to voice an opinion?

[rwinegar]

I didn't want to have to do this because of long holds, transfers, etc, etc, but I called Dell. I would much rather have depended on the experts here. But I am getting conflicting answers. I was informed by a sales person in the business computer area that I can add a single stick of memory to this computer. I do not need to add in pairs. I was also informed that mixing 677MHz with 667MHz will cause no problems. The salesman at Dell was 100% sure of his answer.

http://accessories.us.dell.com/sna/p...&mfgpid=194776

[bistro]

If that is the case, then adding just one more stick of 1GB memory will work, but you will lose the dual-channel memory feature (it will work, just not as efficient). You would be better off adding TWO 1GB stcks to match the other two in order to retain dual-channel capability. Unfortunately, if you are running 32-bit Windows OS, it will only recognize up to 3.25GB of that memory. You are OK if running 64-bit Windows.

[SuperSparks]

I agree, it will work, but you will probably take a performance hit because of losing the dual-channel. But there is no harm in trying it to see how it runs.

[Teknophobia]

Even stranger still, Crucial disagrees with Dell:
http://www.crucial.com/store/listpar...tation%20T5400
Says they must be installed in pairs and that the system doesn't support dual channel memory (I do not believe the latter).

TEk

[Train]

Minimum Memory Dual channel 2 x 512MB
Note: Quad channel recommended minimum memory 4 x 512MB.
http://www.dell.com/content/products...tab=bundlestab


Sounds like a server mobo.
Crucial does say

Slots: 8 (4 banks of 2)
Standard Memory: 1024MB removable
Installed in pairs of modules.

So yes it has dual channel and both say in pairs.

Mismatched ram can:

1. not even able to boot up.
2. lead to hair pulling error messages.
3. Work just fine.

Spec's change on ram all the time. Why I just buy all the ram for a mobo at one time and replace whatever is installed. Sure saves on potentioal headaches.

[bistro]

I guess then the question is whether Dell is requiring it be installed in pairs because it won't work otherwise or simply because the dual channel will not work. Will probably have to go ask the ever-evasive Dell guru somewhere up in the Himalayas...

[Platypus]

As photolady has indicated, you cannot add a single DIMM to a 5400 chipset board. The memory population configurations are shown in section 5.3 commencing from page 293 in the specification here:

http://download.intel.com/design/chi...hts/318610.pdf

There is only one single-DIMM configuration possible (a single DIMM alone), all additions must be in pairs:

"When operating in non-mirrored mode the minimum memory upgrade increment is two identical DIMMs per branch (DIMMs must be identical with respect to size, speed, and organization)."

The memory population configurations are shown in section 5.3 commencing from page 293 in the specification above.

The 5400 MCH is a four-channel controller, with channels paired in two branches. The simplest upgrade option is two more 1GB DIMMS, each in slot 0 of channels 2 and 3. This populates both branches and gives the greatest bandwidth, hence the greatest increase in performance.

Because of the requirement to be identical within a slot position, if different speed memory is to be used, it should instead be fitted within the same branch (ie channels 0 & 1):

"DIMMs that cover a slot position must be identical with respect to size, speed, and organization. DIMMs that cover adjacent slot positions need not be identical."

[bistro]

Then I stand corrected again while sitting down and then standing halfway up to reach for my Coke which was sitting down out of my reach where I was sitting down.

Also sounds like that Dell technician needs to be a little better informed.

[SuperSparks]

All Dell technicians need to be better informed, at least if my experience of them is anything to go by