Z series has DDR2-RAM config???

Merry Christmas, everyone!!!

I found this Z on SonyStyle: VGN-Z540EBB

That Z540EBB is surprisingly said to have DDR2-RAM 1066 although the RAM codename is PC3-8500!

I am confusing about this since I have noticed some incorrect descriptive detailed info when building CTO models on SonyStyle and I also may know that DDR2 RAM 1066 does exist!

Anyone has explanation for this discrepancy??? Does the Z possibly have DDR2-RAM config or is this just another Sony mistake on its specification???

Thanks!!!

Again, wish all of you Merry Christmas and a Happy New Year!!!

 

All Sony Z series are Centrino 2 AND have DD3 RAM
SonyStyle never has specs correct -_-'

 

I wish it did have DDR2 1066, but alas, it's a typo.

At the same speeds, DDR2 will have less latency than DDR3, and I'd take DDR2 1066 over DDR3 1066 any day.

 

There are many typo in Sony Style web, so don't 100% believe it.

 

I realize that usually DDR3 has higher latency but also higher bus speed than DDR2, so, should DDR3-1066 on the Z be faster than DDR2-800 on the SR???

 

The question is like asking what's faster for moving stuff around in a city -- a motorbike or a lorry. Which one will be faster depends on whether you move envelopes or crates.

"Faster" is a combination of bandwidth and latency.
DDR2-800 runs at a lower frequency, so it will feed data slower. However it runs at lower latency, so accessing a single memory page will be faster. Which one is faster thus depends on the usage -- if making lots of quick short memory accesses, DDR2-800 will generally be faster, but if making large memory copies, DDR3-1066 will generally be faster.
If running programs that jump all over the place, or random access databases with small amounts of data, DDR2-800 would probably be the better choice. If copying large amounts of data or watching DVDs, DDR3-1066 would probably be be the better choice.

Note that the CPU also influences this to a large degree. The P9500 with a large 6 MB secondary cache will need to make memory accesses less often for reads, which helps offset a larger latency.

 

Oh, thanks to all of you, you're so knowledgable!!!

May I ask another question: Does the Z540(CTO) have the carbon fiber casing?

 

You make a valid point, but to an end user, these things don't really matter too much.

I don't think a user has much of a choice over how the memory is utilized. So, to choose a memory based on what type of memory access its will do is quite tough.

DDR2-1066 does 1066 million data transfer per second, with peak transfer of 8533 MB/s, with the memory clock running at 266 MHz.

DDR3-1066 does 1066 million data transfer per second, with peak transfer of 8533 MB/s as well, but with the memory running at only 133 MHz (thus the higher latency for this module).

With the cost relatively the same for both architecture as well as data transfer rates, you can decide based on other features. With the 1066 modules, all the DDR3 advantages aren't fully realized just yet, such as max bandwidth of 1600 Mhz (both DDR3-1066 and DDR2-1066 have bandwidth of only 533 MHz), and reduced latency (in terms of time). But one advantage that the DDR3-1066 has over DDR2-1066 would be lower power consumption (up to 30%) due to lower voltage operation. Nice feature to have on a laptop.

There are other things that DDR3 is introducing as well that a quick google search can easily reveal but once again, I don't know if anybody cares. As an end user, all I care about is how 'fast' is it overall, and how much will it cost me, and if I have a laptop, is it an energy hog?

As DDR3 becomes a more mature architecture, it will have a very clear cut advantage over DDR2 in all categories.

So personally, I don't mind the debatable reduction in speed that DDR3 may bring over DDR2 when it allows you to consume less power. However, perhaps somebody could put up a benchmark comparison of these two memory architectures.

 

Here's a link talking about DDR3's advantages.

 

There's also currently higher CAS/RAS latency on DDR-3 RAM, which contributes to the overall latency, although this is likely to improve as DDR-3 matures.
But for now, the memory that Sony delivers is 7-7-7-20, while a typical DDR-2 1066 module will have 5-5-5-18 or thereabouts.

Undoubtedly, DDR-3 is the future, but the future isn't here just yet. Right now, DDR-3 is like the first generation of P4 CPUs, i.e. slower at the same speed than the predecessors except for in special circumstances. It'll improve, but that won't help the current generation of DDR-3 users.

 

I acknowledge that latency seems longer on ddr3, but what I was trying to say is by no means is DDR3-1066 inferior to the DDR2 version. Besides, if you double the memory clock frequency, you'll double the latency numbers that you indicated. Until they change the manufacturing process to 70 nm, the latency will increase in proportion with the memory clock frequency. So, that number really should be given in actual time, rather than number of clock cycles, if that is to become a valid comparison point. DDR3-1066 is as fast overall as DDR2, but its highlight right now for laptop owners is its ability to lengthen time of use while using battery. For a Vaio Z series, long battery life would definitely be one of the prime objectives of the designers.

 

wow wow, arth1 and reaborg, you guys are really knowledgable

I learnt a lot from your feedbacks and I appreciate those of yours

So, DDR3 upsets me a little bit but it seems that the Z should be my final choice

Thanks again, all of you!!!