Ram Difference

Shalom Everyone:
Someone please explain the difference in performance betxween these two Ram stiucks:

PC3-12800 DDR3 and PC3-8500 DDR3.
Thank you.

 

The PC3-12800 is faster than the PC3-8500. If used together, they will both only operate at the PC3-8500 speed. To make sure you get the PC3-12800 speed, use only that speed if installing more than 1 module.

 

The speed you get also depends on your CPU an m/b, but if you have newer models of both it won't matter and what mdonah has written is the thing to consider

(for example, my 2011 laptop will function will function with [certain] only PC3-12800 RAM but that will only function at the speed of PC3-8500)

Dumb_Question
7.March.2016

 

Something else to consider...
My motherboard supports DDR3 1333 MHz. To get that speed, I need two identical (same manufacturer, chip set, capacity, speed) RAM modules.
With only one RAM module, the speed is 667 MHz. I have two non-identical modules and the speed is 667 MHz.

 

That apparent anomaly might just be down to interpretation, 667MHz being 1333MHz at DDR (Double Data Rate), try checking your actual RAM speed with a different software/benchmark. Dual Channel (2x identical sticks) doesn't raise the speed, it allows greater bandwidth as there would be 2x controllers sharing the work load.

CPU-Z or HWiNFO show the base memory speed, Userbenchmark will give you DDR (effective) speed.

Wikipedia.

 

I did. With CPU-Z & HWiNFO, and two other programs.
And I read the motherboard manual. DDR3 RAM runs in over clocking mode - with just 1 module, or 2 non-identical modules, the 'speed' is halved.

 

Did you check with UserBenchmark?

 

Yes.
The RAM speed is null MHz according to UserBenchmark...
SIW and Speccy also show 667 MHz.

The motherboard supports Dual Channel Memory Technology.

 

Do you have a link to the UserBenchmark results?

 

Here you go.
http://www.userbenchmark.com/UserRun/857807

 

Eldon, I don't supposed you have a 'matched pair' of RAM modules, in order to check what speed all these system analysis programs give with them in place (instead 2 mixed types or one module alone) ?

Dumb_Question
12.March.2016

 

No I don't.
When I had 1 module the speed was 667 MHz.
Adding a second different module (brand, capacity, etc.), the speed stayed at 667 MHz.
And the motherboard's FSB is 800 MHz.
I need to upgrade...