Memory for SZ - The Truth

I know there are numerous posts on this, but everybody gives a different answer. Yes, the SZ’s accepts 667mhz DDR2 memory, but…..

(1) Does it down regulate it to 533mhz? If so why especially if FSB is 667mhz?
(2) If it does go to 533mhz is it faster (better) to go with 533mhz memory which has a lower Cas Latency and timing?
(3) Has anyone run a comparison test and is there a noticeable difference?

Thanks for your help.

 

Yes, you can absolutely put a couple of sticks of 667 DDR2 in your SZ.

Is the SZ's mobo secretly rated for up to 667 or just up to 533?

Impossible to know for sure as Sony does not publish this info nor does their BIOS allow one to tweak or even see the actual CPU or RAM timings being used.

I would however guess that could the SZ run the memory at a stable 667 then Sony would do this as it would allow them to advertise this fact as an " enhanced performance feature".

As Sony provides precious little BIOS info at all I have no idea who Sony's OEM supplier is for the motherboard or, more importantly the North/South bridge chipset maker so, given this situation, I can only make an educated guess at their reasons but my first guess would be a combination of stability, heat, and power consumption - and, of course, price.

Running memory at 1:1 with the CPU's FSB [particularly at the speeds we are talking about] requires some reasonably high quality RAM in order to run stable and without a bunch of memory errors. Make no mistake, regardless of the premium we paid for our SZ's Sony is still using the lowest quality [therefore] least expensive RAM they can getaway with and still run stable.

Also, running the CPU and RAM at 1:1 would generate a bit more heat and use a bit more power, both of which are critical factors in a thin-n-light laptop with a small battery like the SZ.

Even mobo maker MSI suggests that RAM should usually be run slower than the CPU FSB for ultimate stability. They will still only "guarantee" 1:1 stability with a very few sticks of validated and very expensive RAM [Corsair XMS, Mushkin, Geil, etc]

I personally have yet to see any PC-5300 667 DDR-2 SO-DIMMs listed at anything faster than CAS 5 or any PC-4200 533 sticks faster than CAS 4. If you happen run across any just send me a couple of 1GB sticks and I would be happy to evaluate them

Still, even at those specs there can't be much difference between 667 @ 5 and 533 @ 4 stock and I know of no BIOS for the SZ that will allow you to OC the RAM timings.

 

Great explanation. Thanks! So save the money and go with 533mhz and Cas4?

 

Newegg.com currently has some pretty high quality 1GB Corsair ValueSelect SO-DIMMs at $80 for 667 and $75 for 533.

If the extra $10 for 667 makes you sleep better at night then I suppose it's worth it. Otherwise I would spend that $10 on a few super high quality blank dual-layer DVD-Rs.

The exception would be if you plan on buying a new 667 notebook sometime within the next year or so...

 

I did buy 2 GB of this RAM for my SZ but it slow down my lappyn (even slower than 1 GB stock) So I switched to OCZ ram PC 4200 with 533 bus speed from new egg and I really love it .

 

OCZ is a good product but the only difference I can see between it and the Corsair is a slightly shorter pre-charge delay [8 vs. 11].

I don't see how that could make a significant difference in performance, particularly when running on batteries - but to each his own.

 

Is it true that for DDR2 both memory sticks need to be the same size?

 

No, they don't have to be but given the SZ's dual-channel memeory architecture you will see significant perfromance gains by using two sticks of equal size.