Noticeable Difference betwen PC3-8500 and PC2 6400?

I am thinking of buying either one of these models Lenovo T400 and HP Elitebook 6930p.

Now rest aside i was curious that is there a real gain in getting a PC3 8500 (DDR3) (in T400) and PC2 6400 (DDR2) (n 6930p)

If i decide to go with 6930p should i:

1) buy 3 GB (1x2GB + 1x1GB) PC3 8500 modules and insert it
2) or buy 1GB PC3 8500 and put in 2nd slot next to 2GB PC2 6400?
3) or leave it, there is no difference.

I did do forum search and did not find a satisfying response....

Thanks
MadEngineer

 

The faster DDR3 RAM is slightly offset by it's higher latency, I don't think there is much difference between the two. However, as time goes on, I'm sure manufacturing will improve and bring the latency down (as is always the case).
Also, I believe you can use only one or the other. That is a decision the manufacturers make in deciding which modules to support. I'm very certain they didn't include support for both, as the pinouts are different. DDR3 has more pins in the memory socket than DDR2, so they are not compatible with each other, so basically whatever comes with said model, is the kind you're stuck with. Lenovo is using DDR3, I'm not sure about the HP. It should say in their specifications at their website.

 

It's either got 2 slots for ddr3 or 2 slots for ddr2, so you CANT put a ddr3 1066 and a ddr2 800 together.
if you use a ddr3 1066 dimm and a ddr3 800 dimm, the ram will run at 800mhz

 

HP comes with DDR2 800 mhz.

Since the chipset is PM45, i though we could remove the DD2 800 and replace it with DDR3 1067.

 

Nope even though chipset supports both DDR2&3 the MFG determines which is used when they put chipset in MoBo.

I have seen two benchmarks for those speeds on this site and the difference too small to matter. Here is a link to those two speeds with 1066FSB it is a Desktop but the relative/comparative value holds in my opinion.

I would not care if DDR2 or DDR3 unless power was a big concern. JEDEC now has DDR2 1066Mhz as a standard. They make for desktop think you will see for notebooks soon so DDR3 has no speed advantage.

 

There's a couple of links in this thread for bandwidth results for Montevina and DDR2 or DDR3. DDR3 wins, but by a very small margin that's probably within the range of experimental error.

John

 

And even if it's out of the range of error, it still isn't noticeable in real life.

 

Depending on if the poster who listed in GB's meant base 10 GB or base 2 GB the difference is 3% or.6%. Neither are large enough to matter.