Can we use two RAMs with different latencies?

[darkavenger143]

Hi all,

I already have 2X1 GB 800 Transcend RAMs in my system....im planning to add Patriot extreme 2X1GB rams. But as you all know both are of different latencies....will it effect my total performance?

 

[Billb2]

If by "it" you mean adding two sticks, well, maybe...total performance wise. The x32 versions of Windows have trouble with 4 gigs.
And, if by "it" you mean the mismatched latencies, then yes, mismatched memory latencies will effect total performance (compared to matched memory). But you can, perhaps, change the latencies.

Perhaps, if you could ask your question in a less general way, a more specific answer would be possible.
Like, what motherboard, what OS, and what are you trying to accomplish?

And it would be "kind" to list the memory specs you are talking about, instead of depending in the fortitude of the responders to look it up. Even a linkey would be "nice". The easier you can make it for the responder, the better chance you have on getting a good response.
http://www.albinoblacksheep.com/flash/posting

 

[BonzaiDuck]

Billb2 is right. My educated guess, and 'ol Bill can correct me if wrong, is that -- if it is going to work -- the latencies for all memories must be set to the those modules which will only run at looser timings.

Some people are finicky about their choice of hardware -- I am one of those people. If I were going to "mix modules," I would do it in matched pairs from the same manufacturer so that the units would only vary by model. And I would hope that the units all used the same basic parts, different only in the "binning" process and therefore rated speeds. But this doesn't mean that using different manufactures of two matched sets wouldn't work. It just means that I, personally, wouldn't do it at all, and if I had to do it, I would still limit my choices of which modules to use.

And obviously, you would only want to run the entire memory configuration at the speed attainable by the slower memory-kit.

 

[Billb2]

Originally posted by: BonzaiDuck
I would do it in matched pairs from the same manufacturer so that the units would only vary by model.

Memory, from the same manufacturer, with same model numbers, and the same specs and can have different "parts", (IC's and eproms). Usually, a Rev. No. change indicates a change in "parts". I find it strange that places like the Egg and ZipZoomFly don't list Rev. Nos....but then, most people are clueless.

 

[darkavenger143]

iam using transcend 800 ram with latencies....5-5-5-12 .....im gonna add patriot extreme 2X1GB ram with latencies.....4-4-4-12

Iam using both Vista and XP 23-bit and Asus P5n-E SLI mbob...

 

[BonzaiDuck]

"XP 23-bit."

Dyslexia is a smart-people's disorder.


On Billb2's comments -- Somewhere I've seen more or less knowledgeable observations that you can "mix pairs" of different-spec RAM, but it wasn't "advised." I'm pretty sure about the rule-of-thumb per cautious latency choices.

But on these newer systems, I'd never do it. My point was -- that if I HAD to do it, I'd do it within those parameters.

But I don't "have to" -- and I won't.

. . . . because Billb2's subliminal advice is basically wise . . .

 

[Billb2]

Originally posted by: BonzaiDuck

. . . . because Billb2's subliminal advice is basically wise . . .

Some clarification:
1.) For everyday use, by a nOOb, your mom, your kid brother, your "know-it-all" neighbor, etc mixed memory is fine. It will show up in Windows, will run at the SPD of the slowest sticks. ...life will be good.
Some rearranging of the sticks into differnt slots may be necessary to get it to run, but with a simple admonishment (to change the sticks around) will get the user on the right track. ...life will be good.
But In today's competitive market place, the memory manufacture will probably have to extend some effort (in support and/or RMA) before the nOOb figures out, (or accidentally stumbles on) the need to move the sticks around. This is the cause of the advice to not use mixed memory, and also unnecessarily high product pricing. It also can waste some of the users money, since he/she may be paying for memory speed that cant be used. But if he/she never looks at memory speeds/timings with CPU-Z or something, ignorance is bliss. ...life will be good.

2.)If ya wanna get "into it", you can manually change the timings and memory speed in the BIOS. The slower memory will probably (depends?) clock up to, or maybe even faster, than the faster memory. Anyway, doing that will get all the memory running as fast as the slowest memory can go. ...life will be good.

3.) For overclocking/benching: The smart people probably know what speed they can get out of memory (by changing Vdimm, timings, and sub timings) before they buy it This is a whole other "science", and beyond the scope of this thread). So they can plan for that in their purchases, and mis-matching ceases to be a issue. ...my Life is good.

Anyone wishing to explore these issues in further detail:
1.) Consult your owner's manual.
2.) Download; A64Info, MemSet 3.4 beta, Thaiphoon Burner, SPDTool_062
3.) Read pertinent threads on the "good" overlocking forums
4.) Google