PC3-10600 (DDR31333 mHz) vs PC3-8500 (DDR3 1066 mHZ) for i5-540

Hey Guys,

I am trying to decide on what memory to get for my laptop (currently deciding between the envy 15, E6510 and T510). The most intensive task I will be doing some SIMPLE HD video editing on it, however when I do it, I want it to go fast. This will be done on vacations, where time is money. Mostly, I will be taking notes in class and surfing on this machine, but I want it to have lots of headroom, because I always have something come up that requires power (such as the occasional adobe photo editing tasks and who knows what else in the future). One note: I keep my laptops for 4 to 5 years before I upgrade.

I am going with an i5-540m processor and can get the 1333 mHz memory for the same price as the 1066 mHz memory on one computer and only have to pay $50 - 75 more on another to upgrade. So it seems simple: just upgrade!

However, I have read reports of higher latency on the 1333 mHz memory as well as some other drawbacks (energy consumption?). Also, I don't even know what the FSB of the i5-540 is...

Can anyone help in clearing this up? I have tried to research but must not be using the proper search terms because I cannot come up with much. ANY help would be greatly appreciated.

 

The i5-540 doesn't use FSB, technically speaking. It only supports a max of 1066MHz RAM, though, so if you buy the 1333MHz it will be running at 1066MHz anyway.

Buy whichever is cheaper, and if they're the same price buy whichever of the two has lower latency. I can't say for sure which it would be unless I see the specs of the RAM.
Chances are it's CAS 9 DDR3-1333 vs CAS 7 DDR3-1066, in which case both have roughly the same latency (~13.1ns vs 13.5ns [the 1333MHz RAM is very slightly slower]), and so the 1333MHz RAM would probably run at the same CAS 7 latency when at the lower 1066MHz clocks.

 

1333 is pointless to get in the i series dual core chips you need a quad core i7 to get benefits from 1333mhz ram so just get the cheaper 1066

 

Or you can burn the RAM using SPD.

 

Thanks for the info guys, I appreciate it.

 

Anyway this is my final SPD Mod.
Frequency > Timing. It is the same RAM Module if you thought I bought a new one...

 

CAS 8 at 800MHz is equal to CAS 5 at 500MHz as far as latency is concerned. That's something you have to keep in mind.

 

I forgot that only Quad Core i7 uses 1333MHZ Memory controller so I reverted to a Kingston Hyper X 1066 RAM SPD settings with XMP after all.

 

i'd just get the cheaper which is usually PC3-8500...

 

Thanks a lot for the info guys!

Weinter,
I really appreciate your effort, but the info is a little over my head. i have always been fuzzy on ram and latencies. Can you explain some of your results or point me to a place where I can get the info to figure it out?

 

Download Thaiphoon burner 6.6 then download the SPD dump for Kingston HyperX RAM then flash the RAM you get a "Kingston HyperX RAM".