SZ18GP, is the memory limited to 533MHz DDR2 speeds?

I have the Vaio SZ18GP from HK and upgraded to Corsair DDR2 667MHz memory but under CPUz it still shows as running at 533MHz. Does anyone else have any success running 667MHz memory at it's proper speed or did Sony cripple this in their bios?

 

I don't think it matters if it is crippled or not, you're not going to see a difference in performance. I have read that some claim faster ram will only work at 533 in the SZ, others claim it works the higher speed just fine. The thing is, if it is running the slower speed, it is also running a lower latency, which is good. It seems the memory bus is pretty easily saturated anyway, so it really won't matter much either way.

 

Not true, I bought the 667MHz memory as it would speed up the Intel graphics chip since that uses the main memory so faster speed = more bandwidth available to it. Reason for using Intel and not the NVidia is that MacOSX supports the Intel graphics fully.
Anyone can confirm whether the Sony SZxx is crippled in it's memory speed?

 

ahaha another Hong Konger.
I upgraded from 512 to 2 Gig
533 -> 667
1 Gig KingMax DDR2 667 Venus * 2
It certainly is running at 667 but with frequency stuck at 266mhz instead of maximum 333mhz
4-4-4-8 timing i think @ 266
8-8-8-16 @ 333 i think
forgot but yeah, it has variable timings @ differnet speeds.
Also my ram is running at Dual Channel mode aswell,
are all your ram sticks identical?

 

Hmm my memory has different timings to yours, at:

400 3-3-3-9
533 4-4-4-12
667 5-5-5-15

I also have 2 x 1Gb so it is running dual channel at least.

If yours is stuck at 266 then is same as mine. I want to know if possible to change to 333, I don't mind the higher latencies.

 

You should run some benchmarks and report results. I know many are interested in this, but there have been no real conclusive results as to the difference in performance. I ran memory bandwidth tests in sisoft sandra, and actually had more memory bandwidth while using the nvidia card, but not by much. That is with the stock 533 memory. I would be interested to see some results of 533 vs 667.

I would venture to guess that your 667 memory will show no improvement over the 533 memory.

 

we cant change the frequency cuz the BIOS is locked. Anyone with 533 1 gig *2 to run the benchmarks?
Provide me link to benchmark util i should use and lets compare our ram kantana

 

Try running Sisoft Sandra from:
http://download.guru3d.com/sandra/

My scores in NVidia mode for memory benchmark were:

Integer 3563 Mb/S
Floating point 3537 Mb/s

 

i thought it was limited to 533
if you put 677 ram into it
it will still underclock it to 533

 

I haven't tried this on my SZ, but on other systems I've seen:
-Running single channel the 667 memory will run at 667.
-Running dual channel the 667 memory will run at 533.
Note that dual channel means that the CPU is reading/writing twice the amount of data at a given frequency than it is in single channel mode.

Compare 667 to 1066 (i.e. 667*1 versus 533*2)... the "slower" memory clock is actually *faster* in memory bandwidth.

 

someone should write to sony and complain

 

Just tried running only one strip of memory for 1Gb results were:

Integer 3294 Mb/s
Floating point 3297 Mb/s

What gives, does the Core Duo only use such an amount of bandwidth or is the memory not running at full potential?

 

It is what I've been trying to tell you that I've been reading around the different tech forums and sites. A single stick of ddr2 533 just about saturates the bus. Running in dual channel doesn't buy a whole lot. Faster memory isn't doing much for you either, because of the increased latency.

A bus can only pass so much data before it cannot handle any more. It appears that the limitation is in the bus, and not the memory speed, or Sony "crippling" the bios. I'm afraid you'll have this same situation on any machine with the same intel chipset. If anyone else here has access to a machine from a different manufacturer, maybe they could run the same memory bandwidth tests to see what the differences are. I'm willing to bet they will be nearly the same.

 

As the Intel chipset supports 667 speeds why does Sony limit it to run at 533 only irrespective of higher latencies or usable bandwidth. It seems to me to be crippling the abilities of the chipset.
I bought PC5300 DDR2 memory expecting it to run at this speed. Other manufacturers don't seem to limit their laptops to only run at 533 speeds so why should Sony be allowed to?

 

it could may aswell be heat issues...

 

I hadn't considered that, but it well may be that limiting the memory speed may reduce power consumption a little. And given that it doesn't appear that there is ANY benefit to the faster memory, I would say it was probably a good thing to do (assuming that it does reduce power consumption).

 

I don't think they are "crippling the chipset". I think the chipset itself is pretty limited on bandwidth, and is not capable of utilizing the faster memory. I have not seen anything that makes me believe that the other manufacturers have better performing machines, due to being able to correctly implement the faster memory. In fact, I think the SZ is at least as fast, if not faster than most other 1.83 CD machines.

Like I said, lets get some apples to apples comparisons using same benchmark suites.

Ask yourself this: Why would Sony "cripple" their machines? (oh, you did ask that)

Answer: They wouldn't. Granted, I don't like the way they do some things, but they aren't stupid. There is no benefit to them "crippling" their machines.

 

So why limit the ability to support faster memory? If that's not crippling then what is it, an 'undocumented feature'? Seriously I hope they fix this in a future bios release as it is limiting the choice of the consumers that buy the machine. I remember that another Sony Vaio previously also had this limitation vaguely remember it being GRxxx I believe the limitation then was running DDR 266 at only DDR200 speeds.
Some countries received a bios update that allowed the faster speed while others suffered from the slower speed. Just don't want to end up in the same situation.

 

The Core Dual has a 166MHz FSB speed. However it's "Quad Pumped" meaning that it can transfer data 4 times on every clock.... that's where Intel comes up with their "666 Mhz" FSB speed. The CPU bus is 64-bits wide, which is 8-bytes. 666MHz multiplied by 8 is 5,328. So the *absolute* theoretical amount of data the CPU can read or write per second is 5328Mb/sec, except there is protocol overhead so that you'll never actually see 5328 Mb/sec.

The DDR2 memory also is 64-bits wide and is "dual pumped". So your "DDR2 533" is really running at 266Mhz clock rate. In any case, since DDR2 533 can move 8 bytes per clock that allows it to reach 4264 Mb/sec. And so DDR2 667 can move the same 8 bytes per clock to allow it to reach 5336 Mb/sec.

Dual channel means that the chipset is running two channels to memory and hence the chipset has twice the available bandwidth to memory.

Let's look at the full CPU->Chipset->Memory path for single channel 533:

CPU--(5.3Mb/sec)-->Chipset--(4.2Mb/sec)-->Memory

Clearly the limiting factor in this case is the Chipset to memory link.
Now let's look at 533 Dual Channel:

CPU--(5.3Mb/sec)-->Chipset--(8.4Mb/sec)-->Memory

As you can see, the CPU front side bus speed is now the limiting factor. That extra 3Mb/sec of extra bandwidth will never be used because the CPU just can't push that much data.

Let's look at the full CPU->Chipset->Memory path for single channel 667:

CPU--(5.3Mb/sec)-->Chipset--(5.3Mb/sec)-->Memory

OK, so now we're in the situation where the CPU and memory are theoretically matched. Again I'll say that due to CPU bus overhead and the inability to write code that perfectly saturates the memory bus, this configuration will most likely be limited by the CPU to chipset link.

And finally the full CPU->Chipset->Memory path for dual channel 667:

CPU--(5.3Mb/sec)-->Chipset--(10.6Mb/sec)-->Memory

The bottleneck here is clearly the CPU to Chipset link. Half of the Chipset to memory bandwidth will *never be used*, because the CPU is incapable of running that fast.

These faster memory speeds make sense in the Pentium 4s, width their 800 and 1066 FSB speeds (able to move 6.4Mb/sec and 8.5Mb/sec respectively). But in the Pentium M family of CPUs (to which the earlier Banias, Dothan and the current Core Duo belong), it doesn't make a lot of sense.

 

so wouldnt it run better if it was in single channel mode with 2 sticks?

 

Latency has very little impact when it comes to overall speed as the most important factor is bandwidth.
You'll only see how latency is having a negative impact when running stuff like benchmark which isn't a typical usage for a laptop!

 

Well, I don't know what to tell you, other than Sony recognized that DDR2 running at 667 has no performance benefit over DDR2 533 in this particular chipset. Limiting support to DDR2 533 speeds may reduce power consumption, so why not use that limitation for some benefit.

How about this:

Would you be less upset if the bios "officially" supported the ddr2 667 speed, but provided the same performance as ddr2 533? Because if Sony allowed your 667 to run at 667, that is what you would have.

 

No other manufacturer is limiting their laptops to 533 speeds only. Why not give the end user the choice of what speed to run the memory at with the benefits if any of higher power savings with the lower speed memory?
I think there is some mistake at Sony to limit the memory speeds, I think we deserve to know the reasoning behind it and an updated bios to unlock the higher speeds. Those consumers paying extra for the higher speed memory but not being able to benefit from it must annoy a lot of users.

 

Well, I agree to a point. The only place where any of this can be measured is in a benchmark of some sort. But if the bandwidth is already used all up, there is no more to benefit from increasing the speed of the data, but lower latency can help out a bit.

What I've been trying to say from the top of this thread is that the ddr2 533 can push more data than the system can handle. This was more clearly illustrated by a previous post. So, why does everyone have such a problem with the fact that their 667 will only run at 533 speed and timing? The bandwidth limitation is an intel design, not Sony's. Why the frustration with Sony?

 

Kantana,
You need to remember that Sony sells a laptop computer *SYSTEM*, not a laptop computer *COMPONENT*. Thus all of their decisions about what to support and how to support it are all meshed together. You'll notice that virtually all of the Sony from-the-factor available memory configurations are dual channel setups... In Sony's judgement they are selling a system that is configured to provide the best performance. It's not a mistake.

In addition to the ongoing power savings by running the lower clock rate, there's also less heat generated. And that means more thermal budget for running the CPU faster. Less heat generation inside the case is better for the hard drive too. And these decisions cascade out to effect the entire laptop.

Plus there's also the testing issue. If Sony were to release a BIOS to support a faster clock rate they'd be testing at least 3 additional memory configurations (socket A with the faster memory, socket B with the faster memory, both sockets with the faster memory), multiplied by all the languages, multiplied by all the CPU options, etc. And all that extra testing would make the laptop more expensive, take longer to get design revisions done, be harder to document, etc. All so that you can get absolutely zero performance benefit but can point to a number of the screen and go (with apologies to Carlos Mencia) "Duh duh duh... 667".

 

What about the Intel integrated graphics, wouldn't that be able to use extra bandwidth? If Sony had mentioned specifically that DDR2 667 would only run at 533 speeds then a lot of users like me could have saved a few $$$ buying the cheaper memory.
That I think is why I am annoyed with Sony, making a laptop that has restrictions which are not disclosed.

 

I piad 400 HKD more for the 667s, ohwell

 

Really.
I have a Toshiba Tecra A7, Asus A6J, both also come with 533 DDR2 memory.

So far, it seems that the only core-duo laptop shipping with 666Mhz RAM is the Apple powerbook and Lenovo
JY

 

I'd note that while the Powerbook ships with 666Mhz memory, it ships with a 1 x 1Gb Single channel configuration instead of the Sony's Dual channel 2 x 512Mb configuration. Thus the memory bandwidth is identical between the shipping Sony and shipping Apple configurations.

 

For HK version of SZ, the spec (both on sony's website and printed brochure) explicitly states that the memory runs at 533. Unfortunately, you need to be technically savvy to decipher the meaning of "MEMORY BUS".

Look here: http://www.sonystyle.com.hk/ss/vaio/product/vgn-sz18gp_c/specifications.html