DDR3 latency.

I have often heard that DDR3 ram has a negligable affect on the speed of a laptop, despite it's higher speed. I have that this is due to latency of DDR3 ram.

What confuses me is although the latency is higher (perphaps 7 7 7 21 vs 5 5 5 15), according to wikipedia, if you measure the latency in ns it is pretty much the same (10ns).

If you take the second paragraph as all true wouldn't two similar systems, the difference between them being one is ddr2 and one ddr3, wouldn't ddr3 outperform ddr2 by a significant amount?

Simplified math:
1066 (mem. speed ddr3) / 800 (pretty much highest ddr2 speed w/o oc) ~ 1.25
knock off 5% for an error margin we get 20% increase in ram speed.

 

While the bandwidth available to DDR3 is much greater, the chipset/CPU can't take advantage of it. Hence why upgrading to faster memory has pretty much zero real life performance advantage. Only when the bottleneck of the computer is raised will you see any performance difference. Typically this is the hard drive and GPU.

 

1066 mhz is a waste.
1600, 1800 mhz show a difference.
Bt they burn a hole in your wallet.

 

Agreed, unless there is some ram that can be mass oc'd

 

I don't think that there is a point to ram faster than 1066 as the max processor FSB for laptops is currently 1066. sgogeta4, i get what you mean but surely there are some applications that see a marked improvement in speed when using DDR3?

 

Really, only benchmarks will show improvement. Imagine your memory speed is equivalent to a 4 lane highway, but you only have 2 cars in it (your limiting factor). There is no way to jam the highway, so even if you increase your highway to 16 lanes (faster memory speed), it won't affect the speed of traffic (because limiting factor is still there).

 

I dont see a point in going ddr3 over my ddr2.

I think companies are jus pushing it for money.

 

me too @ Sili

 

me three @ Sili

Now when it comes down to the price of ddr2 then i shall concider it hehe, can motherboard ram slots be swapped out? I think the 725' mobo does support but doesnt have the right slots.

 

RAM slots are soldered in, and SMB at that. If you really wanted to then you could, but you're likely to damage the sensitive electronics around the RAM slots. And even then your BIOS probably won't support it.

 

As far as desktops go, I've been doing quite a bit of reading recently wrt various mb/DDR3 tri-channel RAM combos, and the i7s kill C2D & quads, along with AMDs which at best can kind of match C2 sometimes. (Also alot of the i7/X58 chipset mbs seems to be rather ... er... tempermental wrt to DRAM parts, etc. almost seem kind of half-baked ATM to me which is incredibly idiotic given their assinine pricing, more than a 920 for decent mbs... lots of chipset heat problems too worst on the "cheap" mbs which makes them worth avoiding IMO unless you do aftermarket chipset cooling)

The problems with gaming ATM seems to be that ATI crossfired cards seem to perform MUCH better than nVidia SLIed cards ATM, but I plan to stick with nVidia in the future since they have nearly infinitely superior drivers along with almost as good chip design. (ATI has really good chip designs, but that's almost entirely negated by their poor driver support.)

As to DDR3 notebooks dunno, but the dual channel DDR3 AM3 AMD CPUs looked OK on latency as well, although their bandwidth is considerably constrained v. tri channel. i7 nbs won't be out until late summer/fall...

6GB Corsair DDR3 three stick matched set, 1600 rated are about $85-95, but really tightly binned stuff can still be almost $200 for 3 sticks.