Matching RAM?

[Dimitri]

I have 4GB of Apacer DDR3 1333 Mhz and I want to get 4GB more.

Do I need to:

1) get the same brand

2) go for another 1333 or can I go 1600?

I think what happens in such cases is that the 1600 stick gets downclocked to 1333, but would there be other problems beyond that or would it all work fine?

 

[Darren]

Just get another 1333MHz stick as it'll downclock to the lower clocked stick anyway. Doesn't have to be the same brand, although note if it's DDR3L or DDR3 and be sure to mach.

 

[Intel_man]

the DDR3L vs DDR3 is a one way matching criteria. If your existing ram is DDR3L, you must get DDR3L when you add more ram. If you have DDR3 ram now, you can get either DDR3L or DDR3 when you add more ram.

The preference for ram is always to match the brand and model, but if that's not possible due to availability or price being too ridiculously expensive vs other brands. Then matching the speed and CAS timing is the next important one to watch for.

 

[Darren]

the DDR3L vs DDR3 is a one way matching criteria. If your existing ram is DDR3L, you must get DDR3L when you add more ram. If you have DDR3 ram now, you can get either DDR3L or DDR3 when you add more ram.

The preference for ram is always to match the brand and model, but if that's not possible due to availability or price being too ridiculously expensive vs other brands. Then matching the speed and CAS timing is the next important one to watch for.

Thanks, should have specified that.

 

[Dimitri]

What kind of problems can come from mismatchedness?

What comes from mismatched brands and what comes if I mismatch latency and voltage?

I'm wondering whether it's just lower performance or instability/not functioning/something else.

the DDR3L vs DDR3 is a one way matching criteria. If your existing ram is DDR3L, you must get DDR3L when you add more ram. If you have DDR3 ram now, you can get either DDR3L or DDR3 when you add more ram.

Hmm... I don't quite understand this. Why does it make a difference what my existing ram is? If I can add DDR3L to DDR3 why not the other way around? The end result is the same, one DDR3 and one DDR3L.

The preference for ram is always to match the brand and model, but if that's not possible due to availability or price being too ridiculously expensive vs other brands. Then matching the speed and CAS timing is the next important one to watch for.

By speed you mean frequency, not latency, right?

What is CAS?

How can I find out what these other characteristics like CAS, latency, voltage (anything else?) are for my RAM?

Just get another 1333MHz stick as it'll downclock to the lower clocked stick anyway. Doesn't have to be the same brand, although note if it's DDR3L or DDR3 and be sure to mach.

I know it'll downclock, but as I may be buying used modules I may have to go for a 1600, so my question is would that mismatchedness cause any problems.

 

[johnb35]

Any mismatch can cause issues whether it be speed, timings, brand, whatever. Alwa yt?gs best to get exact march when possible.

 

[Intel_man]

Hmm... I don't quite understand this. Why does it make a difference what my existing ram is? If I can add DDR3L to DDR3 why not the other way around? The end result is the same, one DDR3 and one DDR3L.

Unless you bought the DDR3L yourself unknowingly that it can run on lower voltage on a mobo that supports DDR3, then it's fine. If you bought a computer that came with DDR3L, there's a chance that the mobo only runs on the lower voltage spec RAM. Therefore, grabbing regular DDR3 would not work.

What is CAS?

Column Access Strobe Latency or short for CL. It's the latency of your memory. The lower number, the better.

How can I find out what these other characteristics like CAS, latency, voltage (anything else?) are for my RAM?

Usually manufacturers have it listed in this format.

Ex: DDR3-1600 CL9 9-9-9-24

The bolded red font is what to look out for. You either get the whole description or they shorten it and only show you "CL9". If you run the RAM below the spec'd speed, you can tighten the CAS timings. I'm not sure if you'll be able to access the timing tables before installation as I've only seen it via CPU-Z software.

 

[Laquer Head]

a 2x4GB kit of DDR3 or DDR3L starts at like $45 usd ..I'd just find out which you need DDR3 or DDR3L and replace what you have with new matching kit.

 

[Dimitri]

By the way, guys, I've found a dirt cheap 8GB DDR3 on ebay out of Hong Kong that has no brand name, but it says it can only run on AMD MBs.

Wtf, what are the odds that this is some funny business? The seller has 98% positive feedback.

 

[Laquer Head]

By the way, guys, I've found a dirt cheap 8GB DDR3 on ebay out of Hong Kong that has no brand name, but it says it can only run on AMD MBs.

Wtf, what are the odds that this is some funny business? The seller has 98% positive feedback.

I'd say about 98% chance...

 

[beers]

I've found a dirt cheap 8GB DDR3 on ebay out of Hong Kong

You'll likely spend the difference (and more) in labor investigating weird issues with your PC if it has problems.

You could always buy a pair of the super cheap and then use your current stick as a backup if you wanted to go down that route. I'd run a lot of passes of memtest86 as well as memtester on Linux to make sure it doesn't have errors or bit flips.