Which RAM module?

[AyatollahPies]

DDR2 PC2-6400 • CL=6 • Unbuffered • NON-ECC • DDR2-800 • 1.8V

or

DDR2 PC2-5300 • CL=5 • Unbuffered • NON-ECC • DDR2-667 • 1.8V

 

 

Memory is something I'm not too knowledgeable on. Both are 2GB sticks and the same price and both are fully compatible with my Netbook.

 

I imagine the difference will be completely negligible for my needs, but I might as well get the quicker of the two.

 

Ta peeps

[FN-GM]

The top one is slightly better.

 

What make are these? I would myself go with the better make.

[kmount]

Be aware if you're putting it in as ADDITIONAL memory it will depend upon what is already in there should it be slower, the faster memory purchased (ie, the top one) will throttle down.

 

If it's going in on its own it'll be fine as FNGM said.

[SYNACK]

It also depends on whether your netbook supports the 800MHz clock speed of the ram. If the chipset only supports 667 or 533 then the second type would be faster as it has a lower collum latency CL than the the 800MHZ stuff. Also if there is going to be another slower chip in the laptop as well you would probably want the one with the lower CL timeings to match the slower RAM and get the most performance.

[tmcd35]

Could some one more knowledgeable on memory technology either confirm or deny an 'urban myth' for me please?

 

I have been lead to believe that the speed the memory runs at is in direct relation to the clock speeds of both the motherboard and the CPU. Even if a mobo supports 800mhz it may not run 800mhz RAM at that speed, and if it is forced to may actually cause the system to slow down due to mis-timing of the memory access.

 

Example.

 

The mobo runs at 333mhz. The CPU would be at 333 x multiplier. The Ram would be 333x2 or 667mhz. IFAIK DDR ram is accessed on the the rise and fall of the main clock beat (thus mobo speed x 2). If the RAM was forced to run at 800mhz instead of 667 then the memory access's need to be skipped as they will occur between clock cycles rather than on the rise/fall edge of a clock cycle.

[SYNACK]

@tmcd35 - It depends on the hardware, where the controller is and how its clockrate is generated in some cases the clock rates avalible to drive the RAM are lower than what the memory is speced to. One case where this is true is in the older Turion x2 CPUs. Article here: Double Power, DDR2 Memory Controller, And Variable Memory Bandwidth - Review Tom's Hardware : AMD's Dual Core Laptops Have Arrived: Introducing the Turion 64 X2 and About Memory Frequencies on AMD Opteron Processors - X-bit labs

 

Older intel chips had memory controllers that were on the seporate on on the motherboard and while a fair few depended on division of the FSB to provide the RAM clockspeed others had their own independent and tweakable clocks that allowd for overclocking in very small increments, example: NVIDIA nForce 680i SLI Chipset Of nForce 600i Series For Intel

 

Both the new Core i7 and the Phenom chips use integrated controlers now but I am reasonably sure that they have devised a better way to handle the clock signal by now but as yet I have not researched it.

[AyatollahPies]

The top one is slightly better.

 

What make are these? I would myself go with the better make.

 

They are both Crucial.

[AyatollahPies]

Be aware if you're putting it in as ADDITIONAL memory it will depend upon what is already in there should it be slower, the faster memory purchased (ie, the top one) will throttle down.

 

If it's going in on its own it'll be fine as FNGM said.

 

It would be replacing the current memory.

 

Thanks for all the help chaps.

[PeterW]

If its an Atom based netbook it will only run at a max of 667Mhz.

[AyatollahPies]

If its an Atom based netbook it will only run at a max of 667Mhz.

 

It is indeed. Thanks for that info PeterW.